libclamav/phishcheck.c
bd912dd8
 /*
  *  Detect phishing, based on URL spoofing detection.
  *
e1cbc270
  *  Copyright (C) 2013-2019 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
  *  Copyright (C) 2007-2013 Sourcefire, Inc.
2023340a
  *
  *  Authors: Török Edvin
bd912dd8
  *
  *  This program is free software; you can redistribute it and/or modify
2023340a
  *  it under the terms of the GNU General Public License version 2 as
38a00199
  *  published by the Free Software Foundation.
bd912dd8
  *
  *  This program is distributed in the hope that it will be useful,
  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  *  GNU General Public License for more details.
  *
  *  You should have received a copy of the GNU General Public License
  *  along with this program; if not, write to the Free Software
  *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
  *  MA 02110-1301, USA.
  */
 
 #if HAVE_CONFIG_H
 #include "clamav-config.h"
 #endif
 
 #ifdef CL_THREAD_SAFE
 #ifndef _REENTRANT
 #define _REENTRANT
 #endif
 #endif
 
 #include <stdio.h>
 #include <string.h>
 #include <ctype.h>
 
43ecd9a1
 #include "clamav.h"
bd912dd8
 #include "others.h"
 #include "htmlnorm.h"
 #include "phishcheck.h"
 #include "phish_domaincheck_db.h"
43ecd9a1
 #include "phish_whitelist.h"
b611b5ff
 #include "regex_list.h"
bd912dd8
 #include "iana_tld.h"
2e11bcdf
 #include "iana_cctld.h"
d66b8812
 #include "scanners.h"
b43205cb
 #include <assert.h>
43ecd9a1
 
b94e66c4
 #include "mpool.h"
 
bd912dd8
 #define DOMAIN_REAL 1
 #define DOMAIN_DISPLAY 0
 
 #define PHISHY_USERNAME_IN_URL 1
288057e9
 #define PHISHY_NUMERIC_IP 2
 #define REAL_IS_MAILTO 4
bd912dd8
 /* this is just a flag, so that the displayed url will be parsed as mailto too, for example
  * <a href='mailto:somebody@yahoo.com'>to:somebody@yahoo.com</a>*/
288057e9
 #define DOMAIN_LISTED 8
 #define PHISHY_CLOAKED_NULL 16
6f60f808
 
bd912dd8
 /*
964a1e73
  * Phishing design documentation
  * -----------------------------
bd912dd8
 
813864ce
 TODO: update this doc whenever behaviour changes
bd912dd8
 
 phishingCheck() determines if @displayedLink is  a legit representation of @realLink.
 
 Steps:
 
813864ce
 1. if _realLink_ == _displayLink_ => CLEAN
bd912dd8
 
 2. url cleanup (normalization)
 - whitespace elimination
813864ce
  strip all spaces, and leading and trailing garbage.
  When matching we have to keep in account whether we stripped any spaces or not.
  See str_fixup_spaces.
bd912dd8
 - html entity conversion
813864ce
 - handle hex-encoded characters
bd912dd8
 - convert hostname to lowercase
 - normalize \ to /
 
 3. Matched the urls against a _whitelist_:
 a _realLink_, _displayedLink_ pair is matched against the _whitelist_.
 the _whitelist_ is a list of pairs of realLink, displayedLink. Any of the elements of those pairs can be a _regex_.
  if url *is found* in _whitelist_ --> *CLEAN*
 
813864ce
 4. URL is looked up in the _domainlist_
bd912dd8
 The _domainlist_ is a list of pairs of realLink, displayedLink (any of which can be regex).
 This is the list of domains we do phishing detection for (such as ebay,paypal,chase,....)
 We can't decide to stop processing here or not, so we just set a flag.
 
 Note(*!*): the flags are modified by the the domainlist checker. If domain is found, then the flags associated with it filter the default compile-time flags.
 
 5. _Hostname_ is extracted from the _displayed URL_.
 It is checked against the _whitelist_, and _domainlist_.
 
 6. Now we know if we want to stop processing.
 If we are only scanning domains in the _domainlist_ (default behaviour), and the url/domain
 isn't found in it, we return (and mark url as not_list/clean).
 If we scan all domains, then the domainlist isn't even checked.
 
 7. URL cloak check.
 check for %00, and hex-encoded IPs in URL.
 
 8. Skip empty displayedURLs
 
 9. SSL mismatch detection.
 Checks if realLink is http, but displayedLink is https or viceversa.
 (by default the SSL detection is done for hrefs only, not for imgs)
 
 10. Hostname of real URL is extracted.
 
 12. Numeric IP detection.
 If url is a numeric IP, then -> phish.
 Maybe we should do DNS lookup?
 
 13. isURL(displayedLink).
 Checks if displayedLink is really a url.
 if not -> clean
 
 14. Hostnames of real, displayedLink are compared. If equal -> clean
 
 15. Extract domain names, and compare. If equal -> clean
 
 16. Do DNS lookups/reverse lookups. Disabled now (too much load/too many lookups). *
 
 For the Whitelist(.wdb)/Domainlist(.pdb) format see regex_list.c (search for Flags)
  *
  */
ec481027
 
288057e9
 /* Constant strings and tables */
 static char empty_string[] = "";
19b3e182
 
ec481027
 static const char dotnet[] = ".net";
 static const char adonet[] = "ado.net";
 static const char aspnet[] = "asp.net";
97ba1aed
 /* ; is replaced by ' ' so omit it here*/
288057e9
 static const char lt[]           = "&lt";
 static const char gt[]           = "&gt";
 static const char src_text[]     = "src";
 static const char href_text[]    = "href";
 static const char mailto[]       = "mailto:";
2e11bcdf
 static const char mailto_proto[] = "mailto://";
288057e9
 static const char https[]        = "https:";
 static const char http[]         = "http:";
 static const char ftp[]          = "ftp:";
 
 static const size_t href_text_len    = sizeof(href_text);
 static const size_t src_text_len     = sizeof(src_text);
 static const size_t dotnet_len       = sizeof(dotnet) - 1;
 static const size_t adonet_len       = sizeof(adonet) - 1;
 static const size_t aspnet_len       = sizeof(aspnet) - 1;
 static const size_t lt_len           = sizeof(lt) - 1;
 static const size_t gt_len           = sizeof(gt) - 1;
 static const size_t mailto_len       = sizeof(mailto) - 1;
 static const size_t mailto_proto_len = sizeof(mailto_proto) - 1;
 static const size_t https_len        = sizeof(https) - 1;
 static const size_t http_len         = sizeof(http) - 1;
 static const size_t ftp_len          = sizeof(ftp) - 1;
ec481027
 
 /* for urls, including mailto: urls, and (broken) http:www... style urls*/
 /* refer to: http://www.w3.org/Addressing/URL/5_URI_BNF.html
  * Modifications: don't allow empty domains/subdomains, such as www..com <- that is no url
  * So the 'safe' char class has been split up
  * */
 /* character classes */
288057e9
 #define URI_digit "0-9"
 #define URI_IP_digits "[" URI_digit "]{1,3}"
f12c2e68
 #define URI_path_start "[/?:]?"
288057e9
 #define URI_numeric_path URI_IP_digits "(\\." URI_IP_digits "){3}" URI_path_start
 #define URI_numeric_URI "(http|https|ftp:(//)?)?" URI_numeric_path
f12c2e68
 #define URI_numeric_fragmentaddress URI_numeric_URI
ec481027
 
 /*Warning: take care when modifying this regex, it has been tweaked, and tuned, just don't break it please.
  * there is fragmentaddress1, and 2  to work around the ISO limitation of 509 bytes max length for string constants*/
288057e9
 static const char numeric_url_regex[] = "^ *" URI_numeric_fragmentaddress " *$";
ec481027
 
 /* generated by contrib/phishing/generate_tables.c */
 static const short int hextable[256] = {
288057e9
     0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
     0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
     0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
     0x0, 0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0x8, 0x9, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
     0x0, 0xa, 0xb, 0xc, 0xd, 0xe, 0xf, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
     0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
     0x0, 0xa, 0xb, 0xc, 0xd, 0xe, 0xf, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
     0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
     0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
     0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
     0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
     0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
     0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
     0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
     0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
     0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0};
ec481027
 
 /* Prototypes*/
288057e9
 static void string_init_c(struct string* dest, char* data);
75fe1251
 static int string_assign_concatenated(struct string* dest, const char* prefix, const char* begin, const char* end);
43ecd9a1
 static void string_assign_null(struct string* dest);
288057e9
 static char* rfind(char* start, char c, size_t len);
43ecd9a1
 static char hex2int(const unsigned char* src);
288057e9
 static enum phish_status phishingCheck(const struct cl_engine* engine, struct url_check* urls);
fc83da82
 static const char* phishing_ret_toString(enum phish_status rc);
bd912dd8
 
fc83da82
 static void url_check_init(struct url_check* urls)
bd912dd8
 {
288057e9
     string_init_c(&urls->realLink, NULL);
     string_init_c(&urls->displayLink, NULL);
     string_init_c(&urls->pre_fixup.pre_displayLink, NULL);
bd912dd8
 }
 
 /* string reference counting implementation,
  * so that: we don't have to keep in mind who allocated what, and when needs to be freed,
34c9315f
  * and thus we won't leak memory*/
bd912dd8
 
fc83da82
 static void string_free(struct string* str)
bd912dd8
 {
288057e9
     for (;;) {
         str->refcount--;
         if (!str->refcount) {
             if (str->ref)       /* don't free, this is a portion of another string */
                 str = str->ref; /* try to free that one*/
             else {
                 if (str->data)
                     free(str->data);
                 break;
             }
         } else
             break;
     }
bd912dd8
 }
 
43ecd9a1
 /* always use the string_assign when assigning to a string, this makes sure the old one's reference count is incremented*/
288057e9
 static void string_assign(struct string* dest, struct string* src)
bd912dd8
 {
288057e9
     string_free(dest);
     src->refcount++;
     dest->data     = src->data;
     dest->refcount = 1;
     dest->ref      = src;
bd912dd8
 }
 
 /* data will be freed when string freed */
fc83da82
 /* it doesn't free old string, use only for initialization
bd912dd8
  * Doesn't allow NULL pointers, they are replaced by pointer to empty string
  * */
288057e9
 static void string_init_c(struct string* dest, char* data)
bd912dd8
 {
288057e9
     dest->refcount = data ? 1 : 0;
     dest->data     = data ? data : empty_string;
     dest->ref      = NULL;
bd912dd8
 }
 
75fe1251
 /* assigns to @dest the string made from concatenating @prefix with the string between @begin and @end */
 static int string_assign_concatenated(struct string* dest, const char* prefix, const char* begin, const char* end)
 {
288057e9
     const size_t prefix_len = strlen(prefix);
     char* ret               = cli_malloc(prefix_len + end - begin + 1);
     if (!ret) {
7cd9337a
         cli_errmsg("Phishcheck: Unable to allocate memory for string_assign_concatenated\n");
288057e9
         return CL_EMEM;
241e7eb1
     }
288057e9
     strncpy(ret, prefix, prefix_len);
     strncpy(ret + prefix_len, begin, end - begin);
     ret[prefix_len + end - begin] = '\0';
     string_free(dest);
     string_init_c(dest, ret);
     return CL_SUCCESS;
75fe1251
 }
 
bd912dd8
 /* make a copy of the string between start -> end*/
288057e9
 static int string_assign_dup(struct string* dest, const char* start, const char* end)
bd912dd8
 {
288057e9
     char* ret = cli_malloc(end - start + 1);
     if (!ret) {
241e7eb1
         cli_errmsg("Phishcheck: Unable to allocate memory for string_assign_dup\n");
288057e9
         return CL_EMEM;
241e7eb1
     }
288057e9
     strncpy(ret, start, end - start);
     ret[end - start] = '\0';
bd912dd8
 
288057e9
     string_free(dest);
     string_init_c(dest, ret);
     return CL_SUCCESS;
bd912dd8
 }
 
43ecd9a1
 static void string_assign_null(struct string* dest)
bd912dd8
 {
288057e9
     if (dest) {
         string_free(dest);
         dest->data     = empty_string;
         dest->refcount = -1; /* don't free it! */
         dest->ref      = NULL;
     }
bd912dd8
 }
 
 /* this string uses portion of another string*/
288057e9
 static void string_assign_ref(struct string* dest, struct string* ref, char* data)
bd912dd8
 {
288057e9
     string_free(dest);
     ref->refcount++;
     dest->data     = data;
     dest->refcount = 1;
     dest->ref      = ref;
bd912dd8
 }
 
fc83da82
 static void free_if_needed(struct url_check* url)
bd912dd8
 {
288057e9
     string_free(&url->realLink);
     string_free(&url->displayLink);
     string_free(&url->pre_fixup.pre_displayLink);
bd912dd8
 }
 
288057e9
 static int build_regex(regex_t* preg, const char* regex, int nosub)
bd912dd8
 {
288057e9
     int rc;
     cli_dbgmsg("Phishcheck: Compiling regex: %s\n", regex);
     rc = cli_regcomp(preg, regex, REG_EXTENDED | REG_ICASE | (nosub ? REG_NOSUB : 0));
     if (rc) {
 
         size_t buflen = cli_regerror(rc, preg, NULL, 0);
         char* errbuf  = cli_malloc(buflen);
 
         if (errbuf) {
             cli_regerror(rc, preg, errbuf, buflen);
             cli_errmsg("Phishcheck: Error in compiling regex:%s\nDisabling phishing checks\n", errbuf);
             free(errbuf);
         } else
             cli_errmsg("Phishcheck: Error in compiling regex, disabling phishing checks. Additionally an Out-of-memory error was encountered while generating a detailed error message\n");
         return 1;
     }
     return CL_SUCCESS;
bd912dd8
 }
 
 /* allocates memory */
288057e9
 static int get_host(const char* URL, int isReal, int* phishy, const char** hstart, const char** hend)
bd912dd8
 {
288057e9
     int rc, ismailto = 0;
     const char* start;
     const char* end = NULL;
     if (!URL) {
         *hstart = *hend = NULL;
         return 0;
     }
     start = strstr(URL, "://");
     if (!start) {
         if (!strncmp(URL, mailto, mailto_len)) {
             start    = URL + mailto_len;
             ismailto = 1;
         } else if (!isReal && *phishy & REAL_IS_MAILTO) {
             /* it is not required to use mailto: in the displayed url, they might use to:, or whatever */
             end   = URL + strlen(URL) + 1;
             start = URL + strcspn(URL, ": ") + 1;
             if (start == end)
                 start = URL;
             ismailto = 1;
         } else {
             start = URL; /*URL without protocol*/
             if (isReal)
                 cli_dbgmsg("Phishcheck: Real URL without protocol: %s\n", URL);
             else
                 ismailto = 2; /*no-protocol, might be mailto, @ is no problem*/
         }
     } else
         start += 3; /* :// */
 
     if (!ismailto || !isReal) {
         const char *realhost, *tld;
 
         do {
             end      = start + strcspn(start, ":/?");
             realhost = strchr(start, '@');
 
             if (realhost == NULL || (start != end && realhost > end)) {
                 /*don't check beyond end of hostname*/
                 break;
             }
 
             tld = strrchr(realhost, '.');
             rc  = tld ? !!in_tld_set(tld, strlen(tld)) : 0;
             if (rc < 0)
                 return rc;
             if (rc)
                 *phishy |= PHISHY_USERNAME_IN_URL; /* if the url contains a username that is there just to fool people,
81040d73
 			     					     like http://banksite@example.com/ */
288057e9
             start = realhost + 1;                  /*skip the username*/
         } while (realhost);                        /*skip over multiple @ characters, text following last @ character is the real host*/
     } else if (ismailto && isReal)
         *phishy |= REAL_IS_MAILTO;
 
     if (!end) {
         end = start + strcspn(start, ":/?"); /*especially important for mailto:somebody@yahoo.com?subject=...*/
         if (!end)
             end = start + strlen(start);
     }
     *hstart = start;
     *hend   = end;
     return 0;
bd912dd8
 }
 
 /*
  * memrchr isn't standard, so I use this
  */
288057e9
 static char*
 rfind(char* start, char c, size_t len)
bd912dd8
 {
288057e9
     char* p;
5c23fc2f
 
288057e9
     if (start == NULL)
         return NULL;
5c23fc2f
 
288057e9
     for (p = start + len; (p >= start) && (*p != c); p--)
         ;
     return (p < start) ? NULL : p;
bd912dd8
 }
 
288057e9
 static void get_domain(struct string* dest, struct string* host)
bd912dd8
 {
288057e9
     char* domain;
     char* tld = strrchr(host->data, '.');
     if (!tld) {
         cli_dbgmsg("Phishcheck: Encountered a host without a tld? (%s)\n", host->data);
         string_assign(dest, host);
         return;
     }
     if (in_cctld_set(tld + 1, strlen(tld + 1))) {
         const char* countrycode = tld + 1;
         tld                     = rfind(host->data, '.', tld - host->data - 1);
         if (!tld) {
             cli_dbgmsg("Phishcheck: Weird, a name with only 2 levels (%s)\n",
                        host->data);
             string_assign(dest, host);
             return;
         }
         if (!in_tld_set(tld + 1, countrycode - tld - 2)) {
             string_assign_ref(dest, host, tld + 1);
             return; /*it was a name like: subdomain.domain.uk, return domain.uk*/
         }
     }
     /*we need to strip one more level, this is the actual domain*/
     domain = rfind(host->data, '.', tld - host->data - 1);
     if (!domain) {
         string_assign(dest, host);
         return; /* it was like sourceforge.net?*/
     }
     string_assign_ref(dest, host, domain + 1);
bd912dd8
 }
 
fc83da82
 static int isNumeric(const char* host)
bd912dd8
 {
288057e9
     int len = strlen(host);
     int a, b, c, d, n = 0;
     /* 1.2.3.4 -> 7*/
     /* 127.127.127.127 -> 15*/
     if (len < 7 || len > 15)
         return 0;
     sscanf(host, "%d.%d.%d.%d%n", &a, &b, &c, &d, &n);
     if (n == len)
         if (a >= 0 && a <= 256 && b >= 0 && b <= 256 && c >= 0 && c <= 256 && d >= 0 && d <= 256)
             return 1;
     return 0;
bd912dd8
 }
 
fc83da82
 static int isSSL(const char* URL)
bd912dd8
 {
288057e9
     return URL ? !strncmp(https, URL, https_len) : 0;
bd912dd8
 }
 
5c23fc2f
 /* deletes @what from the string @begin.
bd912dd8
  * @what_len: length of @what, excluding the terminating \0 */
5c23fc2f
 static void
288057e9
 str_hex_to_char(char** begin, const char** end)
bd912dd8
 {
288057e9
     char *firsthex, *sbegin_;
     char* sbegin        = *begin;
     const char* str_end = *end;
5c23fc2f
 
288057e9
     if (str_end <= &sbegin[1])
         return;
5c23fc2f
 
288057e9
     /* convert leading %xx*/
     if (sbegin[0] == '%') {
         sbegin[2] = hex2int((unsigned char*)sbegin + 1);
         sbegin += 2;
     }
     *begin = sbegin++;
     do {
         sbegin_  = sbegin;
         firsthex = NULL;
         while (sbegin + 3 <= str_end) {
             if (sbegin + 3 <= str_end && sbegin[0] == '%') {
                 const char* src = sbegin + 3;
                 if (isxdigit(sbegin[1]) && isxdigit(sbegin[2])) {
                     *sbegin = hex2int((unsigned char*)sbegin + 1);
                     if (*sbegin == '%' && !firsthex)
                         firsthex = sbegin;
                     /* move string */
                     memmove(sbegin + 1, src, str_end - src + 1);
                     str_end -= 2;
                 }
             }
             sbegin++;
         }
         sbegin = sbegin_;
     } while (firsthex);
     *end = str_end;
bd912dd8
 }
5c23fc2f
 
 /*
  * deletes @what from the string @begin.
  * @what_len: length of @what, excluding the terminating \0
  */
 static void
288057e9
 str_strip(char** begin, const char** end, const char* what, size_t what_len)
bd912dd8
 {
288057e9
     char* sbegin        = *begin;
     const char* str_end = *end;
     const char* str_end_what;
     size_t cmp_len = what_len;
5c23fc2f
 
288057e9
     if (begin == NULL || str_end <= sbegin)
         return;
5c23fc2f
 
288057e9
     /*if(str_end < (sbegin + what_len))
5c23fc2f
 		return;*/
288057e9
     if (strlen(sbegin) < what_len)
         return;
5c23fc2f
 
288057e9
     /* strip leading @what */
     while (cmp_len && !strncmp(sbegin, what, cmp_len)) {
         sbegin += what_len;
5c23fc2f
 
288057e9
         if (cmp_len > what_len)
             cmp_len -= what_len;
         else
             cmp_len = 0;
     }
5c23fc2f
 
288057e9
     /* strip trailing @what */
     if (what_len <= (size_t)(str_end - sbegin)) {
         str_end_what = str_end - what_len + 1;
         while ((str_end_what > sbegin) &&
                (strncmp(str_end_what, what, what_len) == 0)) {
             str_end -= what_len;
             str_end_what -= what_len;
         }
     }
5c23fc2f
 
288057e9
     *begin = sbegin++;
     while (sbegin + what_len <= str_end) {
         while (sbegin + what_len <= str_end && !strncmp(sbegin, what, what_len)) {
             const char* src = sbegin + what_len;
             /* move string */
             memmove(sbegin, src, str_end - src + 1);
             str_end -= what_len;
         }
         sbegin++;
     }
     *end = str_end;
bd912dd8
 }
 
43ecd9a1
 /* replace every occurrence of @c in @str with @r*/
288057e9
 static void str_replace(char* str, const char* end, char c, char r)
bd912dd8
 {
288057e9
     for (; str <= end; str++) {
         if (*str == c)
             *str = r;
     }
bd912dd8
 }
288057e9
 static void str_make_lowercase(char* str, size_t len)
bd912dd8
 {
288057e9
     for (; len; str++, len--) {
         *str = tolower(*str);
     }
bd912dd8
 }
 
288057e9
 #define fix32(x) ((x) < 32 ? 32 : (x))
43ecd9a1
 static void clear_msb(char* begin)
bd912dd8
 {
288057e9
     for (; *begin; begin++)
         *begin = fix32((*begin) & 0x7f);
bd912dd8
 }
 
 /*
  * Particularly yahoo puts links like this in mails:
81040d73
  * http:/ /www.example.com
bd912dd8
  * So first step: delete space between / /
  *
  * Next there could be possible links like this:
  * <a href="phishlink">w  w w . e b a y . c o m</a>
  * Here we need to strip spaces to get this picked up.
  *
  * Next there are links like:
  * <a href="www.yahoo.com">Check out yahoo.com</a>
  * Here we add a ., so we get: check.out.yahoo.com (it won't trigger)
  *
6a929d83
  * Old Rule for adding .: if substring from right contains dot, then add dot,
5c23fc2f
  *	otherwise strip space
6a929d83
  * New Rule: strip all spaces
  *  strip leading and trailing garbage
bd912dd8
  *
  */
43ecd9a1
 static void
288057e9
 str_fixup_spaces(char** begin, const char** end)
bd912dd8
 {
288057e9
     char* sbegin     = *begin;
     const char* send = *end;
     if (!sbegin || !send || send < sbegin)
         return;
     /* strip spaces */
     str_strip(&sbegin, &send, " ", 1);
     /* strip leading/trailing garbage */
     while (!isalnum(sbegin[0] & 0xff) && sbegin <= send) sbegin++;
     while (!isalnum(send[0] & 0xff) && send >= sbegin) send--;
 
     /* keep terminating slash character*/
     if (send[1] == '/') send++;
     *begin = sbegin;
     *end   = send;
bd912dd8
 }
 
 /* allocates memory */
fc83da82
 static int
288057e9
 cleanupURL(struct string* URL, struct string* pre_URL, int isReal)
bd912dd8
 {
288057e9
     char* begin = URL->data;
     const char* end;
     size_t len;
813864ce
 
288057e9
     clear_msb(begin);
     /*if(begin == NULL)
bd912dd8
 		return;*/
288057e9
     /*TODO: handle hex-encoded IPs*/
     while (isspace(*begin))
         begin++;
 
     len = strlen(begin);
     if (len == 0) {
         string_assign_null(URL);
         string_assign_null(pre_URL);
         return 0;
     }
15b08fbb
 
288057e9
     end = begin + len - 1;
     /*cli_dbgmsg("%d %d\n", end-begin, len);*/
     if (begin >= end) {
         string_assign_null(URL);
         string_assign_null(pre_URL);
         return 0;
     }
     while (isspace(*end))
         end--;
     /* From mailscanner, my comments enclosed in {} */
     if (!strncmp(begin, dotnet, dotnet_len) || !strncmp(begin, adonet, adonet_len) || !strncmp(begin, aspnet, aspnet_len)) {
         string_assign_null(URL);
         string_assign_null(pre_URL);
     } else {
         size_t host_len;
         char* host_begin;
         int rc;
 
         str_replace(begin, end, '\\', '/');
         /* find beginning of hostname, because:
fa51ec00
 		 * - we want to keep only protocol, host, and
 		 *  strip path & query parameter(s)
f12c2e68
 		 * - we want to make hostname lowercase*/
288057e9
         host_begin = strchr(begin, ':');
         while (host_begin && (host_begin < end) && (host_begin[1] == '/')) host_begin++;
         if (!host_begin)
             host_begin = begin;
         else
             host_begin++;
         host_len = strcspn(host_begin, ":/?");
         if (host_begin + host_len > end + 1) {
             /* prevent hostname extending beyond end, it can happen
fa51ec00
 			 * if we have spaces at the end, we don't want those part of
f12c2e68
 			 * the hostname */
288057e9
             host_len = end - host_begin + 1;
         } else {
             /* cut the URL after the hostname */
             /* @end points to last character we want to be part of the URL */
             end = host_begin + host_len - 1;
         }
         host_begin[host_len] = '\0';
         /* convert hostname to lowercase, but only hostname! */
         str_make_lowercase(host_begin, host_len);
         /* some broken MUAs put > in the href, and then
7c6c3e13
 		 * we get a false positive, so remove them */
288057e9
         str_replace(begin, end, '<', ' ');
         str_replace(begin, end, '>', ' ');
         str_replace(begin, end, '\"', ' ');
         str_replace(begin, end, ';', ' ');
         str_strip(&begin, &end, lt, lt_len);
         str_strip(&begin, &end, gt, gt_len);
         /* convert %xx to real value */
         str_hex_to_char(&begin, &end);
         if (isReal) {
             /* htmlnorm converts \n to space, so we have to strip spaces */
             str_strip(&begin, &end, " ", 1);
         } else {
             /* trim space */
             while ((begin <= end) && (begin[0] == ' ')) begin++;
             while ((begin <= end) && (end[0] == ' ')) end--;
         }
         if ((rc = string_assign_dup(isReal ? URL : pre_URL, begin, end + 1))) {
             string_assign_null(URL);
             return rc;
         }
         if (!isReal) {
             str_fixup_spaces(&begin, &end);
             if ((rc = string_assign_dup(URL, begin, end + 1))) {
                 return rc;
             }
         }
     }
     return 0;
bd912dd8
 }
 
3da4dd4c
 /* -------end runtime disable---------*/
288057e9
 int phishingScan(cli_ctx* ctx, tag_arguments_t* hrefs)
bd912dd8
 {
288057e9
     /* TODO: get_host and then apply regex, etc. */
     int i;
     struct phishcheck* pchk = (struct phishcheck*)ctx->engine->phishcheck;
     /* check for status of whitelist fatal error, etc. */
     if (!pchk || pchk->is_disabled)
         return CL_CLEAN;
 
     if (!ctx->found_possibly_unwanted && !SCAN_ALLMATCHES)
         *ctx->virname = NULL;
b43205cb
 #if 0
2e11bcdf
 	FILE *f = fopen("/home/edwin/quarantine/urls","r");
 	if(!f)
 		abort();
 	while(!feof(f)) {
 		struct url_check urls;
 		char line1[4096];
 		char line2[4096];
 		char line3[4096];
 
 		fgets(line1, sizeof(line1), f);
 		fgets(line2, sizeof(line2), f);
 		fgets(line3, sizeof(line3), f);
 		if(strcmp(line3, "\n") != 0) {
 			strcpy(line1, line2);
 			strcpy(line2, line3);
 			fgets(line3, sizeof(line3), f);
 			while(strcmp(line3, "\n") != 0) {
 				fgets(line3, sizeof(line3),f);
 			}
 		}
 		urls.flags = CL_PHISH_ALL_CHECKS;
 		urls.link_type = 0;
 		string_init_c(&urls.realLink, line1);
 		string_init_c(&urls.displayLink, line2);
 		string_init_c(&urls.pre_fixup.pre_displayLink, NULL);
 		urls.realLink.refcount=-1;
 		urls.displayLink.refcount=-1;
 		int rc = phishingCheck(ctx->engine, &urls);
 	}
 	fclose(f);
 	return 0;
b43205cb
 #endif
288057e9
     for (i = 0; i < hrefs->count; i++) {
         struct url_check urls;
         enum phish_status rc;
         urls.flags     = strncmp((char*)hrefs->tag[i], href_text, href_text_len) ? (CL_PHISH_ALL_CHECKS & ~CHECK_SSL) : CL_PHISH_ALL_CHECKS;
         urls.link_type = 0;
         if (!strncmp((char*)hrefs->tag[i], src_text, src_text_len)) {
             if (!(urls.flags & CHECK_IMG_URL))
                 continue;
             urls.link_type |= LINKTYPE_IMAGE;
         }
         urls.always_check_flags = 0;
         if (SCAN_HEURISTIC_PHISHING_SSL_MISMATCH) {
             urls.always_check_flags |= CHECK_SSL;
         }
         if (SCAN_HEURISTIC_PHISHING_CLOAK) {
             urls.always_check_flags |= CHECK_CLOAKING;
         }
         string_init_c(&urls.realLink, (char*)hrefs->value[i]);
         string_init_c(&urls.displayLink, (char*)hrefs->contents[i]);
         string_init_c(&urls.pre_fixup.pre_displayLink, NULL);
 
         urls.realLink.refcount    = -1;
         urls.displayLink.refcount = -1; /*don't free these, caller will free*/
         if (strcmp((char*)hrefs->tag[i], "href")) {
             char* url;
             url                   = urls.realLink.data;
             urls.realLink.data    = urls.displayLink.data;
             urls.displayLink.data = url;
         }
bd912dd8
 
288057e9
         rc = phishingCheck(ctx->engine, &urls);
         if (pchk->is_disabled)
             return CL_CLEAN;
         free_if_needed(&urls);
         cli_dbgmsg("Phishcheck: Phishing scan result: %s\n", phishing_ret_toString(rc));
         switch (rc) /*TODO: support flags from ctx->options,*/
         {
             case CL_PHISH_CLEAN:
                 continue;
             case CL_PHISH_NUMERIC_IP:
                 cli_append_possibly_unwanted(ctx, "Heuristics.Phishing.Email.Cloaked.NumericIP");
                 break;
             case CL_PHISH_CLOAKED_NULL:
                 cli_append_possibly_unwanted(ctx, "Heuristics.Phishing.Email.Cloaked.Null"); /*fakesite%01%00@fake.example.com*/
                 break;
             case CL_PHISH_SSL_SPOOF:
                 cli_append_possibly_unwanted(ctx, "Heuristics.Phishing.Email.SSL-Spoof");
                 break;
             case CL_PHISH_CLOAKED_UIU:
                 cli_append_possibly_unwanted(ctx, "Heuristics.Phishing.Email.Cloaked.Username"); /*http://banksite@fake.example.com*/
                 break;
             case CL_PHISH_HASH0:
                 cli_append_possibly_unwanted(ctx, "Heuristics.Safebrowsing.Suspected-malware_safebrowsing.clamav.net");
                 break;
             case CL_PHISH_HASH1:
                 cli_append_possibly_unwanted(ctx, "Heuristics.Phishing.URL.Blacklisted");
                 break;
             case CL_PHISH_HASH2:
                 cli_append_possibly_unwanted(ctx, "Heuristics.Safebrowsing.Suspected-phishing_safebrowsing.clamav.net");
                 break;
             case CL_PHISH_NOMATCH:
             default:
                 cli_append_possibly_unwanted(ctx, "Heuristics.Phishing.Email.SpoofedDomain");
                 break;
         }
     }
     return CL_CLEAN;
bd912dd8
 }
 
43ecd9a1
 static char hex2int(const unsigned char* src)
3da4dd4c
 {
288057e9
     return (src[0] == '0' && src[1] == '0') ? 0x1 : /* don't convert %00 to \0, use 0x1
19b3e182
  		      * this value is also used by cloak check*/
288057e9
                hextable[src[0]] << 4 | hextable[src[1]];
3da4dd4c
 }
 
ec481027
 static void free_regex(regex_t* p)
3da4dd4c
 {
288057e9
     if (p) {
         cli_regfree(p);
     }
3da4dd4c
 }
 
102cd430
 cl_error_t phishing_init(struct cl_engine* engine)
3da4dd4c
 {
288057e9
     struct phishcheck* pchk;
     if (!engine->phishcheck) {
544fa973
         pchk = engine->phishcheck = MPOOL_MALLOC(engine->mempool, sizeof(struct phishcheck));
288057e9
         if (!pchk) {
241e7eb1
             cli_errmsg("Phishcheck: Unable to allocate memory for initialization\n");
288057e9
             return CL_EMEM;
241e7eb1
         }
288057e9
         pchk->is_disabled = 1;
     } else {
         pchk = engine->phishcheck;
         if (!pchk)
             return CL_ENULLARG;
         if (!pchk->is_disabled) {
             /* already initialized */
             return CL_SUCCESS;
         }
     }
ec481027
 
288057e9
     cli_dbgmsg("Initializing phishcheck module\n");
ec481027
 
288057e9
     if (build_regex(&pchk->preg_numeric, numeric_url_regex, 1)) {
544fa973
         MPOOL_FREE(engine->mempool, pchk);
288057e9
         engine->phishcheck = NULL;
         return CL_EFORMAT;
     }
     pchk->is_disabled = 0;
     cli_dbgmsg("Phishcheck module initialized\n");
     return CL_SUCCESS;
3da4dd4c
 }
 
 void phishing_done(struct cl_engine* engine)
 {
288057e9
     struct phishcheck* pchk = engine->phishcheck;
     cli_dbgmsg("Cleaning up phishcheck\n");
     if (pchk && !pchk->is_disabled) {
         free_regex(&pchk->preg_numeric);
     }
     whitelist_done(engine);
     domainlist_done(engine);
     if (pchk) {
         cli_dbgmsg("Freeing phishcheck struct\n");
544fa973
         MPOOL_FREE(engine->mempool, pchk);
288057e9
     }
     cli_dbgmsg("Phishcheck cleaned up\n");
3da4dd4c
 }
 
2e11bcdf
 /*ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz*/
 static const uint8_t URI_alpha[256] = {
288057e9
     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
     0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
     1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0,
     0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
     1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0,
     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
2e11bcdf
 
 /*!"$%&'()*,-0123456789@ABCDEFGHIJKLMNOPQRSTUVWXYZ_abcdefghijklmnopqrstuvwxyz*/
 static const uint8_t URI_xalpha_nodot[256] = {
288057e9
     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
     0, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 0, 0,
     1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0,
     1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
     1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 1,
     0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
     1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0,
     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
2e11bcdf
 
dfc0c031
 /*!"#$%&'()*+,-0123456789@ABCDEFGHIJKLMNOPQRSTUVWXYZ_abcdefghijklmnopqrstuvwxyz*/
2e11bcdf
 static const uint8_t URI_xpalpha_nodot[256] = {
288057e9
     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
     0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0,
     1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0,
     1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
     1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 1,
     0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
     1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0,
     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
 
 static inline int validate_uri_xalphas_nodot(const char* start, const char* end)
2e11bcdf
 {
288057e9
     const unsigned char* p;
     for (p = (const unsigned char*)start; p < (const unsigned char*)end; p++) {
         if (!URI_xalpha_nodot[*p])
             return 0;
     }
     return 1;
2e11bcdf
 }
 
288057e9
 static inline int validate_uri_xpalphas_nodot(const char* start, const char* end)
2e11bcdf
 {
288057e9
     const unsigned char* p;
     for (p = (const unsigned char*)start; p < (const unsigned char*)end; p++) {
         if (!URI_xpalpha_nodot[*p])
             return 0;
     }
     /* must have at least on char */
     return p > (const unsigned char*)start;
2e11bcdf
 }
 
288057e9
 static inline int validate_uri_ialpha(const char* start, const char* end)
2e11bcdf
 {
288057e9
     const unsigned char* p = (const unsigned char*)start;
     if (start >= end || !URI_alpha[*p])
         return 0;
     return validate_uri_xalphas_nodot(start + 1, end);
2e11bcdf
 }
 
bd912dd8
 /*
  * Only those URLs are identified as URLs for which phishing detection can be performed.
  */
7e32c99e
 static int isURL(char* URL, int accept_anyproto)
bd912dd8
 {
288057e9
     char *last_tld_end = NULL, *q;
     const char *start  = NULL, *p, *end;
     int has_proto      = 0;
     if (!URL)
         return 0;
 
     while (*URL == ' ') URL++;
     switch (URL[0]) {
         case 'h':
             if (strncmp(URL, https, https_len) == 0)
                 start = URL + https_len - 1;
             else if (strncmp(URL, http, http_len) == 0)
                 start = URL + http_len - 1;
             break;
         case 'f':
             if (strncmp(URL, ftp, ftp_len) == 0)
                 start = URL + ftp_len - 1;
             break;
         case 'm':
             if (strncmp(URL, mailto_proto, mailto_proto_len) == 0)
                 start = URL + mailto_proto_len - 1;
             break;
     }
     if (start && start[1] == '/' && start[2] == '/') {
         /* has a valid protocol, it is a URL */
         return 1;
     }
     start = accept_anyproto ? strchr(URL, ':') : start;
     if (start) {
         /* validate URI scheme */
         if (validate_uri_ialpha(URL, start)) {
             /* skip :// */
             if (start[1] == '/') {
                 start += 2;
                 if (*start == '/')
                     start++;
             } else
                 start++;
             has_proto = 1;
         } else
             start = URL; /* scheme invalid */
     } else
         start = URL;
     p   = start;
     end = strchr(p, '/');
     if (!end)
         end = p + strlen(p);
 
     if (!has_proto && (q = memchr(p, '@', end - p))) {
         /* don't phishcheck if displayed URL is email, but do phishcheck if
7da37b96
 	     * foo.TLD@host is used */
288057e9
         const char* q2 = q - 1;
         while (q2 > p && *q2 != '.') q2--;
         if (q2 == p || !in_tld_set(q2 + 1, q - q2 - 1))
             return 0;
     }
7da37b96
 
288057e9
     do {
         q = strchr(p, '.');
         if (q > end)
             break;
         if (q) {
             if (!validate_uri_xpalphas_nodot(p, q))
                 return 0;
             if (accept_anyproto && in_tld_set(p, q - p))
                 last_tld_end = q;
             p = q + 1;
         }
     } while (q);
     if (p == start) /* must have at least one dot in the URL */
         return 0;
     if (end < p)
         end = p;
     while (*end == ' ' && end > p) --end;
 
     if (in_tld_set(p, end - p))
         return 1;
     if (!accept_anyproto)
         return 0;
     if (last_tld_end) {
         *last_tld_end = '\0';
         return 1;
     }
     return 0;
bd912dd8
 }
 
830c1eae
 /*
  * Check if this is a real URL, which basically means to check if it has a known URL scheme (http,https,ftp).
  * This prevents false positives with outbind:// and blocked:: links.
  */
2e11bcdf
 #if 0
830c1eae
 static int isRealURL(const struct phishcheck* pchk,const char* URL)
 {
 	return URL ? !cli_regexec(&pchk->preg_realurl,URL,0,NULL,0) : 0;
 }
2e11bcdf
 #endif
830c1eae
 
288057e9
 static int isNumericURL(const struct phishcheck* pchk, const char* URL)
bd912dd8
 {
288057e9
     return URL ? !cli_regexec(&pchk->preg_numeric, URL, 0, NULL, 0) : 0;
bd912dd8
 }
 
 /* Cleans up @urls
  * If URLs are identical after cleanup it will return CL_PHISH_CLEANUP_OK.
  * */
fc83da82
 static enum phish_status cleanupURLs(struct url_check* urls)
bd912dd8
 {
288057e9
     if (urls->flags & CLEANUP_URL) {
         cleanupURL(&urls->realLink, NULL, 1);
         cleanupURL(&urls->displayLink, &urls->pre_fixup.pre_displayLink, 0);
         if (!urls->displayLink.data || !urls->realLink.data)
             return CL_PHISH_NODECISION;
         if (!strcmp(urls->realLink.data, urls->displayLink.data))
             return CL_PHISH_CLEAN;
     }
     return CL_PHISH_NODECISION;
bd912dd8
 }
 
288057e9
 static int url_get_host(struct url_check* url, struct url_check* host_url, int isReal, int* phishy)
bd912dd8
 {
288057e9
     const char *start, *end;
     struct string* host = isReal ? &host_url->realLink : &host_url->displayLink;
     const char* URL     = isReal ? url->realLink.data : url->displayLink.data;
     int rc;
     if ((rc = get_host(URL, isReal, phishy, &start, &end))) {
         return rc;
     }
     if (!start || !end) {
         string_assign_null(host);
     } else if ((rc = string_assign_concatenated(host, ".", start, end))) {
         return rc;
     }
813864ce
 
288057e9
     cli_dbgmsg("Phishcheck:host:%s\n", host->data);
813864ce
 
288057e9
     if (!host->data || (isReal && (host->data[0] == '\0' || strstr(host->data, ".."))) || *phishy & REAL_IS_MAILTO || strchr(host->data, ' ')) {
         /* no host,
813864ce
 		 * link without domain, such as: href="/isapi.dll?...
 		 * mailto:
 		 * spaces in hostname
f12c2e68
 		 * double dots
813864ce
 		 */
288057e9
         cli_dbgmsg("Phishcheck:skipping invalid host\n");
         return CL_PHISH_CLEAN;
     }
     if (isNumeric(host->data)) {
         *phishy |= PHISHY_NUMERIC_IP;
     }
     if (!isReal) {
         url->pre_fixup.host_start                                    = start - URL;
         url->pre_fixup.host_end                                      = end - URL;
         url->pre_fixup.pre_displayLink.data[url->pre_fixup.host_end] = '\0';
     }
     return CL_PHISH_NODECISION;
bd912dd8
 }
5c23fc2f
 
288057e9
 static void url_get_domain(struct url_check* url, struct url_check* domains)
5c23fc2f
 {
288057e9
     get_domain(&domains->realLink, &url->realLink);
     get_domain(&domains->displayLink, &url->displayLink);
     domains->flags = url->flags;
bd912dd8
 }
 
288057e9
 static enum phish_status phishy_map(int phishy, enum phish_status fallback)
bd912dd8
 {
288057e9
     if (phishy & PHISHY_USERNAME_IN_URL)
         return CL_PHISH_CLOAKED_UIU;
     else if (phishy & PHISHY_NUMERIC_IP)
         return CL_PHISH_NUMERIC_IP;
     else
         return fallback;
bd912dd8
 }
 
102cd430
 static cl_error_t whitelist_check(const struct cl_engine* engine, struct url_check* urls, int hostOnly)
bd912dd8
 {
288057e9
     return whitelist_match(engine, urls->realLink.data, urls->displayLink.data, hostOnly);
bd912dd8
 }
 
102cd430
 static cl_error_t hash_match(const struct regex_matcher* rlist, const char* host, size_t hlen, const char* path, size_t plen, int* prefix_matched)
b611b5ff
 {
288057e9
     const char* virname;
b43205cb
 #if 0
 	char s[1024];
 	strncpy(s, host, hlen);
 	strncpy(s+hlen, path, plen);
 	s[hlen+plen] = '\0';
 	cli_dbgmsg("hash lookup for: %s\n",s);
 #endif
cd94be7a
     UNUSEDPARAM(prefix_matched);
 
288057e9
     if (rlist->sha256_hashes.bm_patterns) {
         const char hexchars[] = "0123456789ABCDEF";
         unsigned char h[65];
         unsigned char sha256_dig[32];
         unsigned i;
         void* sha256;
b2e7c931
 
da6e06dd
         sha256 = cl_hash_init("sha256");
f077c617
         if (!(sha256))
             return CL_EMEM;
 
288057e9
         cl_update_hash(sha256, (void*)host, hlen);
         cl_update_hash(sha256, (void*)path, plen);
da6e06dd
         cl_finish_hash(sha256, sha256_dig);
b2e7c931
 
288057e9
         for (i = 0; i < 32; i++) {
             h[2 * i]     = hexchars[sha256_dig[i] >> 4];
             h[2 * i + 1] = hexchars[sha256_dig[i] & 0xf];
         }
         h[64] = '\0';
         cli_dbgmsg("Looking up hash %s for %s(%u)%s(%u)\n", h, host, (unsigned)hlen, path, (unsigned)plen);
450466f9
 #if 0
a3d029b9
 	    if (prefix_matched) {
6ad45a29
 		if (cli_bm_scanbuff(sha256_dig, 4, &virname, NULL, &rlist->hostkey_prefix,0,NULL,NULL,NULL) == CL_VIRUS) {
d38d251d
 		    cli_dbgmsg("prefix matched\n");
a3d029b9
 		    *prefix_matched = 1;
 		} else
 		    return CL_SUCCESS;
 	    }
450466f9
 #endif
288057e9
         if (cli_bm_scanbuff(sha256_dig, 32, &virname, NULL, &rlist->sha256_hashes, 0, NULL, NULL, NULL) == CL_VIRUS) {
             cli_dbgmsg("This hash matched: %s\n", h);
             switch (*virname) {
                 case 'W':
                     cli_dbgmsg("Hash is whitelisted, skipping\n");
                     break;
                 case '1':
                     return CL_PHISH_HASH1;
                 case '2':
                     return CL_PHISH_HASH2;
                 default:
                     return CL_PHISH_HASH0;
             }
         }
     }
     return CL_SUCCESS;
b43205cb
 }
b611b5ff
 
b43205cb
 #define URL_MAX_LEN 1024
 #define COMPONENTS 4
102cd430
 enum phish_status cli_url_canon(const char* inurl, size_t len, char* urlbuff, size_t dest_len, char** host, size_t* hostlen, const char** path, size_t* pathlen)
b43205cb
 {
288057e9
     char *url, *p, *last;
     char *host_begin, *path_begin;
     const char* urlend = urlbuff + len;
     size_t host_len, path_len;
 
     dest_len -= 3;
     strncpy(urlbuff, inurl, dest_len);
     urlbuff[dest_len] = urlbuff[dest_len + 1] = urlbuff[dest_len + 2] = '\0';
     url                                                               = urlbuff;
 
     /* canonicalize only real URLs, with a protocol */
     host_begin = strchr(url, ':');
     if (!host_begin)
         return CL_PHISH_CLEAN;
     ++host_begin;
 
     /* ignore username in URL */
     while ((host_begin < urlend) && *host_begin == '/') ++host_begin;
     host_len = strcspn(host_begin, ":/?");
     p        = memchr(host_begin, '@', host_len);
     if (p)
         host_begin = p + 1;
     url = host_begin;
     /* repeatedly % unescape characters */
     str_hex_to_char(&url, &urlend);
     host_begin = url;
     len        = urlend - url;
     /* skip to beginning of hostname */
     while ((host_begin < urlend) && *host_begin == '/') ++host_begin;
     while (*host_begin == '.' && host_begin < urlend) ++host_begin;
 
     last = strchr(host_begin, '/');
     p    = host_begin;
     while (p < urlend) {
         if (p + 2 < urlend && *p == '/' && p[1] == '.') {
             if (p[2] == '/') {
                 /* remove /./ */
                 if (p + 3 < urlend)
                     memmove(p + 1, p + 3, urlend - p - 3);
                 urlend -= 2;
             } else if (p[2] == '.' && (p[3] == '/' || p[3] == '\0') && last) {
                 /* remove /component/../ */
                 if (p + 4 < urlend)
                     memmove(last + 1, p + 4, urlend - p - 4);
                 urlend -= 3 + (p - last);
             }
         }
         if (*p == '/')
             last = p;
         p++;
     }
     p  = &url[urlend - url];
     *p = '\0';
 
     p = host_begin;
     while (p < urlend && p + 2 < url + dest_len && urlend < urlbuff + dest_len) {
         unsigned char c = *p;
         if (c <= 32 || c >= 127 || c == '%' || c == '#') {
             /* convert non-ascii characters back to % escaped */
             const char hexchars[] = "0123456789ABCDEF";
             memmove(p + 3, p + 1, urlend - p - 1);
             *p++ = '%';
             *p++ = hexchars[c >> 4];
             *p   = hexchars[c & 0xf];
             urlend += 2;
         }
         p++;
     }
     *p     = '\0';
     urlend = p;
     len    = urlend - url;
     /* determine end of hostname */
     host_len   = strcspn(host_begin, ":/?");
     path_begin = host_begin + host_len;
     if (host_len <= len) {
         /* url without path, use a single / */
         memmove(path_begin + 2, path_begin + 1, len - host_len);
         *path_begin++ = '/';
         *path_begin++ = '\0';
     } else
         path_begin = url + len;
     if (url + len >= path_begin) {
         path_len = url + len - path_begin + 1;
         p        = strchr(path_begin, '#');
         if (p) {
             /* ignore anchor */
             *p       = '\0';
             path_len = p - path_begin;
         }
         *path = path_begin;
     } else {
         path_len = 0;
         *path    = "";
     }
     /* lowercase entire URL */
     str_make_lowercase(host_begin, host_len);
     *host    = host_begin;
     *hostlen = host_len;
     *pathlen = path_len;
     return CL_PHISH_NODECISION;
4e46d65d
 }
 
102cd430
 static cl_error_t url_hash_match(const struct regex_matcher* rlist, const char* inurl, size_t len)
4e46d65d
 {
288057e9
     size_t j, k, ji, ki;
     char* host_begin;
     const char* path_begin;
     const char* component;
     size_t path_len;
     size_t host_len;
     char* p;
102cd430
     enum phish_status phish_rc;
     cl_error_t rc;
     int prefix_matched = 0;
288057e9
     const char* lp[COMPONENTS + 1];
     size_t pp[COMPONENTS + 2];
     char urlbuff[URL_MAX_LEN + 3]; /* htmlnorm truncates at 1024 bytes + terminating null + slash + host end null */
     unsigned count;
 
     if (!rlist || !rlist->sha256_hashes.bm_patterns) {
         /* no hashes loaded -> don't waste time canonicalizing and
b02aff65
 		 * looking up */
288057e9
         return CL_SUCCESS;
     }
     if (!inurl)
         return CL_EMEM;
 
102cd430
     phish_rc = cli_url_canon(inurl, len, urlbuff, sizeof(urlbuff), &host_begin, &host_len, &path_begin, &path_len);
     if (phish_rc == CL_PHISH_CLEAN)
         return CL_CLEAN;
288057e9
 
     /* get last 5 components of hostname */
     j         = COMPONENTS;
     component = strrchr(host_begin, '.');
     while (component && j > 0) {
         do {
             --component;
         } while (*component != '.' && component > host_begin);
         if (*component != '.')
             component = NULL;
         if (component)
             lp[j--] = component + 1;
     }
     lp[j] = host_begin;
 
     /* get first 5 components of path */
     pp[0] = path_len;
     if (path_len) {
         pp[1] = strcspn(path_begin, "?");
         if (pp[1] != pp[0])
             k = 2;
         else
             k = 1;
         pp[k++] = 0;
         while (k < COMPONENTS + 2) {
             p = strchr(path_begin + pp[k - 1] + 1, '/');
             if (p && p > path_begin) {
                 pp[k++] = p - path_begin + 1;
             } else
                 break;
         }
     } else
         k = 1;
     count = 0;
     for (ki = k; ki > 0;) {
         --ki;
         for (ji = COMPONENTS + 1; ji > j;) {
             /* lookup last 2 and 3 components of host, as hostkey prefix,
a3d029b9
 		 * if not matched, shortcircuit lookups */
288057e9
             int need_prefixmatch = (count < 2 && !prefix_matched) &&
                                    rlist->hostkey_prefix.bm_patterns;
             --ji;
             assert(pp[ki] <= path_len);
             /* lookup prefix/suffix hashes of URL */
             rc = hash_match(rlist, lp[ji], host_begin + host_len - lp[ji] + 1, path_begin, pp[ki],
                             need_prefixmatch ? &prefix_matched : NULL);
102cd430
             if (CL_CLEAN != rc) {
288057e9
                 return rc;
             }
             count++;
450466f9
 #if 0
a3d029b9
 		if (count == 2 && !prefix_matched && rlist->hostkey_prefix.bm_patterns) {
b02aff65
 		    /* if hostkey is not matched, don't bother calculating
 		     * hashes for other parts of the URL, they are not in the DB
 		     */
a3d029b9
 		    cli_dbgmsg("hostkey prefix not matched, short-circuiting lookups\n");
 		    return CL_SUCCESS;
b43205cb
 		}
450466f9
 #endif
288057e9
         }
     }
     return CL_SUCCESS;
b611b5ff
 }
 
bd912dd8
 /* urls can't contain null pointer, caller must ensure this */
288057e9
 static enum phish_status phishingCheck(const struct cl_engine* engine, struct url_check* urls)
bd912dd8
 {
288057e9
     struct url_check host_url;
     int rc                        = CL_PHISH_NODECISION;
     int phishy                    = 0;
     const struct phishcheck* pchk = (const struct phishcheck*)engine->phishcheck;
21d213d7
 
4321c03f
     char* realData    = NULL;
     char* displayData = NULL;
 
288057e9
     if (!urls->realLink.data)
         return CL_PHISH_CLEAN;
21d213d7
 
288057e9
     cli_dbgmsg("Phishcheck:Checking url %s->%s\n", urls->realLink.data,
                urls->displayLink.data);
bd912dd8
 
288057e9
     if (!isURL(urls->realLink.data, 0)) {
         cli_dbgmsg("Real 'url' is not url:%s\n", urls->realLink.data);
         return CL_PHISH_CLEAN;
     }
b43205cb
 
288057e9
     if ((rc = url_hash_match(engine->domainlist_matcher, urls->realLink.data, strlen(urls->realLink.data)))) {
         if (rc == CL_PHISH_CLEAN) {
             cli_dbgmsg("not analyzing, not a real url: %s\n", urls->realLink.data);
             return CL_PHISH_CLEAN;
         } else {
             cli_dbgmsg("Hash matched for: %s\n", urls->realLink.data);
             return rc;
         }
     }
b43205cb
 
288057e9
     if (!strcmp(urls->realLink.data, urls->displayLink.data))
         return CL_PHISH_CLEAN; /* displayed and real URL are identical -> clean */
585fa365
 
288057e9
     if (urls->displayLink.data[0] == '\0') {
         return CL_PHISH_CLEAN;
     }
816d66a8
 
288057e9
     if ((rc = cleanupURLs(urls))) {
         /* it can only return an error, or say its clean;
813864ce
 		 * it is not allowed to decide it is phishing */
288057e9
         return rc < 0 ? rc : CL_PHISH_CLEAN;
     }
bd912dd8
 
288057e9
     cli_dbgmsg("Phishcheck:URL after cleanup: %s->%s\n", urls->realLink.data,
                urls->displayLink.data);
f12c2e68
 
288057e9
     if ((!isURL(urls->displayLink.data, 1)) &&
         ((phishy & PHISHY_NUMERIC_IP && !isNumericURL(pchk, urls->displayLink.data)) ||
          !(phishy & PHISHY_NUMERIC_IP))) {
         cli_dbgmsg("Displayed 'url' is not url:%s\n", urls->displayLink.data);
         return CL_PHISH_CLEAN;
     }
830c1eae
 
fa51ec00
     /*
      * Whitelist X-type WDB signatures:  X:RealURL:DisplayedURL
      * Eg:
      *      X:.+\.benign\.com([/?].*)?:.+\.benign\.de
      */
288057e9
     if (whitelist_check(engine, urls, 0))
         return CL_PHISH_CLEAN; /* if url is whitelisted don't perform further checks */
bd912dd8
 
fa51ec00
     /*
      * Match R-type PDB signatures:  R:RealURL:DisplayedURL
      * Eg:
      *      R:.+\.malicious\.net([/?].*)?:.+\.benign\.com
      */
4321c03f
     /* Provide copies of the oirinal URL's, because domainlist_match() may modify the buffer,
        and we don't want that to happen in this case. */
     realData    = cli_strdup(urls->realLink.data);
     if (!realData) {
         cli_errmsg("Phishcheck: Failed to allocate memory for temporary real link string.\n");
         return CL_PHISH_CLEAN;
     }
     displayData = cli_strdup(urls->displayLink.data);
     if (!displayData) {
         cli_errmsg("Phishcheck: Failed to allocate memory for temporary display link string.\n");
         return CL_PHISH_CLEAN;
     }
     if (domainlist_match(engine, realData, displayData, &urls->pre_fixup, 0)) {
fa51ec00
         phishy |= DOMAIN_LISTED;
     }
4321c03f
     free(realData);
     free(displayData);
bd912dd8
 
fa51ec00
     /*
      * Get copy of URLs stripped down to just the FQDN.
      */
     url_check_init(&host_url);
288057e9
     if ((rc = url_get_host(urls, &host_url, DOMAIN_DISPLAY, &phishy))) {
         free_if_needed(&host_url);
         return rc < 0 ? rc : CL_PHISH_CLEAN;
     }
fa51ec00
     if ((rc = url_get_host(urls, &host_url, DOMAIN_REAL, &phishy))) {
         free_if_needed(&host_url);
         return rc < 0 ? rc : CL_PHISH_CLEAN;
     }
bd912dd8
 
fa51ec00
     /*
      * Exit early if the realLink and displayLink are the same.
      */
     if (!strcmp(urls->realLink.data, urls->displayLink.data)) {
         free_if_needed(&host_url);
         return CL_PHISH_CLEAN;
     }
 
     /*
      * Whitelist M-type WDB signatures: M:RealHostname:DisplayedHostname
      * Eg:
      *      M:email.isbenign.com:benign.com
      */
     if (whitelist_check(engine, &host_url, 1)) {
         free_if_needed(&host_url);
         return CL_PHISH_CLEAN;
     }
 
     /*
      * Match H-type PDB signatures:  H:DisplayedHostname
      * Eg:
      *      H:malicious.com
      */
288057e9
     if (domainlist_match(engine, host_url.displayLink.data, host_url.realLink.data, &urls->pre_fixup, 1)) {
         phishy |= DOMAIN_LISTED;
     } else {
         urls->flags &= urls->always_check_flags;
         /* don't return, we may need to check for ssl/cloaking */
     }
19b3e182
 
288057e9
     /* link type filtering must occur after last domainlist_match */
     if (urls->link_type & LINKTYPE_IMAGE && !(urls->flags & CHECK_IMG_URL)) {
         free_if_needed(&host_url);
         return CL_PHISH_CLEAN; /* its listed, but this link type is filtered */
     }
bd912dd8
 
288057e9
     if (urls->flags & CHECK_CLOAKING) {
         /*Checks if URL is cloaked.
43ecd9a1
 		Should we check if it contains another http://, https://?
bd912dd8
 		No because we might get false positives from redirect services.*/
288057e9
         if (strchr(urls->realLink.data, 0x1)) {
             free_if_needed(&host_url);
             return CL_PHISH_CLOAKED_NULL;
         }
     }
bd912dd8
 
288057e9
     if (urls->flags & CHECK_SSL && isSSL(urls->displayLink.data) && !isSSL(urls->realLink.data)) {
         free_if_needed(&host_url);
         return CL_PHISH_SSL_SPOOF;
     }
bd912dd8
 
288057e9
     if (!(phishy & DOMAIN_LISTED)) {
         free_if_needed(&host_url);
         return CL_PHISH_CLEAN;
     }
ff9845c0
 
288057e9
     {
         struct url_check domain_url;
         url_check_init(&domain_url);
         url_get_domain(&host_url, &domain_url);
         if (!strcmp(domain_url.realLink.data, domain_url.displayLink.data)) {
             free_if_needed(&host_url);
             free_if_needed(&domain_url);
             return CL_PHISH_CLEAN;
         }
         free_if_needed(&domain_url);
     }
bd912dd8
 
288057e9
     free_if_needed(&host_url);
     /*we failed to find a reason why the 2 URLs are different, this is definitely phishing*/
     return phishy_map(phishy, CL_PHISH_NOMATCH);
bd912dd8
 }
 
fc83da82
 static const char* phishing_ret_toString(enum phish_status rc)
bd912dd8
 {
288057e9
     switch (rc) {
         case CL_PHISH_CLEAN:
             return "Clean";
         case CL_PHISH_CLOAKED_NULL:
             return "Link URL is cloaked (null byte %00)";
         case CL_PHISH_CLOAKED_UIU:
             return "Link URL contains username, and real<->displayed hosts don't match.";
             /*username is a legit domain, and after the @ comes the evil one*/
         case CL_PHISH_SSL_SPOOF:
             return "Visible links is SSL, real link is not";
         case CL_PHISH_NOMATCH:
             return "URLs are way too different";
         case CL_PHISH_HASH0:
         case CL_PHISH_HASH1:
         case CL_PHISH_HASH2:
             return "Blacklisted";
         default:
             return "Unknown return code";
     }
bd912dd8
 }