/* Copyright (C) 2007-2014 Open Information Security Foundation * * You can copy, redistribute or modify this Program under the terms of * the GNU General Public License version 2 as published by the Free * Software Foundation. * * 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 * version 2 along with this program; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA * 02110-1301, USA. */ /** * \file * * \author Pablo Rincon * * Implements the ssh.softwareversion keyword * You can match over the software version string of ssh, and it will * be compared from the beginning of the string so you can say for * example ssh.softwareversion:"PuTTY" and it can match, or you can * also specify the version, something like * ssh.softwareversion:"PuTTY-Release-0.55" * I find this useful to match over a known vulnerable server/client * software version incombination to other checks, so you can know * that the risk is higher */ #include "suricata-common.h" #include "threads.h" #include "debug.h" #include "decode.h" #include "detect.h" #include "detect-parse.h" #include "detect-engine.h" #include "detect-engine-mpm.h" #include "detect-engine-state.h" #include "flow.h" #include "flow-var.h" #include "flow-util.h" #include "util-debug.h" #include "util-unittest.h" #include "util-unittest-helper.h" #include "app-layer.h" #include "app-layer-parser.h" #include "app-layer-ssh.h" #include "detect-ssh-software-version.h" #include "stream-tcp.h" /** * \brief Regex for parsing the softwareversion string */ #define PARSE_REGEX "^\\s*\"?\\s*?([0-9a-zA-Z\\:\\.\\-\\_\\+\\s+]+)\\s*\"?\\s*$" static pcre *parse_regex; static pcre_extra *parse_regex_study; int DetectSshSoftwareVersionMatch (ThreadVars *, DetectEngineThreadCtx *, Flow *, uint8_t, void *, Signature *, SigMatch *); static int DetectSshSoftwareVersionSetup (DetectEngineCtx *, Signature *, char *); void DetectSshSoftwareVersionRegisterTests(void); void DetectSshSoftwareVersionFree(void *); void DetectSshSoftwareVersionRegister(void); /** * \brief Registration function for keyword: ssh.softwareversion */ void DetectSshSoftwareVersionRegister(void) { sigmatch_table[DETECT_AL_SSH_SOFTWAREVERSION].name = "ssh.softwareversion"; sigmatch_table[DETECT_AL_SSH_SOFTWAREVERSION].Match = NULL; sigmatch_table[DETECT_AL_SSH_SOFTWAREVERSION].AppLayerMatch = DetectSshSoftwareVersionMatch; sigmatch_table[DETECT_AL_SSH_SOFTWAREVERSION].alproto = ALPROTO_SSH; sigmatch_table[DETECT_AL_SSH_SOFTWAREVERSION].Setup = DetectSshSoftwareVersionSetup; sigmatch_table[DETECT_AL_SSH_SOFTWAREVERSION].Free = DetectSshSoftwareVersionFree; sigmatch_table[DETECT_AL_SSH_SOFTWAREVERSION].RegisterTests = DetectSshSoftwareVersionRegisterTests; const char *eb; int eo; int opts = 0; SCLogDebug("registering ssh.softwareversion rule option"); parse_regex = pcre_compile(PARSE_REGEX, opts, &eb, &eo, NULL); if (parse_regex == NULL) { SCLogError(SC_ERR_PCRE_COMPILE, "Compile of \"%s\" failed at offset %" PRId32 ": %s", PARSE_REGEX, eo, eb); goto error; } parse_regex_study = pcre_study(parse_regex, 0, &eb); if (eb != NULL) { SCLogError(SC_ERR_PCRE_STUDY, "pcre study failed: %s", eb); goto error; } return; error: return; } /** * \brief match the specified version on a ssh session * * \param t pointer to thread vars * \param det_ctx pointer to the pattern matcher thread * \param p pointer to the current packet * \param m pointer to the sigmatch that we will cast into DetectSshSoftwareVersionData * * \retval 0 no match * \retval 1 match */ int DetectSshSoftwareVersionMatch (ThreadVars *t, DetectEngineThreadCtx *det_ctx, Flow *f, uint8_t flags, void *state, Signature *s, SigMatch *m) { SCEnter(); DetectSshSoftwareVersionData *ssh = (DetectSshSoftwareVersionData *)m->ctx; SshState *ssh_state = (SshState *)state; if (ssh_state == NULL) { SCLogDebug("no ssh state, no match"); SCReturnInt(0); } int ret = 0; if ((flags & STREAM_TOCLIENT) && (ssh_state->srv_hdr.flags & SSH_FLAG_VERSION_PARSED)) { SCLogDebug("looking for ssh server softwareversion %s length %"PRIu16" on %s", ssh->software_ver, ssh->len, ssh_state->srv_hdr.software_version); ret = (strncmp((char *) ssh_state->srv_hdr.software_version, (char *) ssh->software_ver, ssh->len) == 0)? 1 : 0; } else if ((flags & STREAM_TOSERVER) && (ssh_state->cli_hdr.flags & SSH_FLAG_VERSION_PARSED)) { SCLogDebug("looking for ssh client softwareversion %s length %"PRIu16" on %s", ssh->software_ver, ssh->len, ssh_state->cli_hdr.software_version); ret = (strncmp((char *) ssh_state->cli_hdr.software_version, (char *) ssh->software_ver, ssh->len) == 0)? 1 : 0; } SCReturnInt(ret); } /** * \brief This function is used to parse IPV4 ip_id passed via keyword: "id" * * \param idstr Pointer to the user provided id option * * \retval id_d pointer to DetectSshSoftwareVersionData on success * \retval NULL on failure */ DetectSshSoftwareVersionData *DetectSshSoftwareVersionParse (char *str) { DetectSshSoftwareVersionData *ssh = NULL; #define MAX_SUBSTRINGS 30 int ret = 0, res = 0; int ov[MAX_SUBSTRINGS]; ret = pcre_exec(parse_regex, parse_regex_study, str, strlen(str), 0, 0, ov, MAX_SUBSTRINGS); if (ret < 1 || ret > 3) { SCLogError(SC_ERR_PCRE_MATCH, "invalid ssh.softwareversion option"); goto error; } if (ret > 1) { const char *str_ptr = NULL; res = pcre_get_substring((char *)str, ov, MAX_SUBSTRINGS, 1, &str_ptr); if (res < 0) { SCLogError(SC_ERR_PCRE_GET_SUBSTRING, "pcre_get_substring failed"); goto error; } /* We have a correct id option */ ssh = SCMalloc(sizeof(DetectSshSoftwareVersionData)); if (unlikely(ssh == NULL)) goto error; ssh->software_ver = (uint8_t *)SCStrdup((char *)str_ptr); if (ssh->software_ver == NULL) { goto error; } pcre_free_substring(str_ptr); ssh->len = strlen((char *)ssh->software_ver); SCLogDebug("will look for ssh %s", ssh->software_ver); } return ssh; error: if (ssh != NULL) DetectSshSoftwareVersionFree(ssh); return NULL; } /** * \brief this function is used to add the parsed "id" option * \brief into the current signature * * \param de_ctx pointer to the Detection Engine Context * \param s pointer to the Current Signature * \param idstr pointer to the user provided "id" option * * \retval 0 on Success * \retval -1 on Failure */ static int DetectSshSoftwareVersionSetup (DetectEngineCtx *de_ctx, Signature *s, char *str) { DetectSshSoftwareVersionData *ssh = NULL; SigMatch *sm = NULL; ssh = DetectSshSoftwareVersionParse(str); if (ssh == NULL) goto error; /* Okay so far so good, lets get this into a SigMatch * and put it in the Signature. */ sm = SigMatchAlloc(); if (sm == NULL) goto error; if (s->alproto != ALPROTO_UNKNOWN && s->alproto != ALPROTO_SSH) { SCLogError(SC_ERR_CONFLICTING_RULE_KEYWORDS, "rule contains conflicting keywords."); goto error; } sm->type = DETECT_AL_SSH_SOFTWAREVERSION; sm->ctx = (void *)ssh; s->flags |= SIG_FLAG_APPLAYER; s->alproto = ALPROTO_SSH; SigMatchAppendSMToList(s, sm, DETECT_SM_LIST_AMATCH); return 0; error: if (ssh != NULL) DetectSshSoftwareVersionFree(ssh); if (sm != NULL) SCFree(sm); return -1; } /** * \brief this function will free memory associated with DetectSshSoftwareVersionData * * \param id_d pointer to DetectSshSoftwareVersionData */ void DetectSshSoftwareVersionFree(void *ptr) { if (ptr == NULL) return; DetectSshSoftwareVersionData *ssh = (DetectSshSoftwareVersionData *)ptr; if (ssh->software_ver != NULL) SCFree(ssh->software_ver); SCFree(ssh); } #ifdef UNITTESTS /* UNITTESTS */ /** * \test DetectSshSoftwareVersionTestParse01 is a test to make sure that we parse * a software version correctly */ int DetectSshSoftwareVersionTestParse01 (void) { DetectSshSoftwareVersionData *ssh = NULL; ssh = DetectSshSoftwareVersionParse("PuTTY_1.0"); if (ssh != NULL && strncmp((char *) ssh->software_ver, "PuTTY_1.0", 9) == 0) { DetectSshSoftwareVersionFree(ssh); return 1; } return 0; } /** * \test DetectSshSoftwareVersionTestParse02 is a test to make sure that we parse * the software version correctly */ int DetectSshSoftwareVersionTestParse02 (void) { DetectSshSoftwareVersionData *ssh = NULL; ssh = DetectSshSoftwareVersionParse("\"SecureCRT-4.0\""); if (ssh != NULL && strncmp((char *) ssh->software_ver, "SecureCRT-4.0", 13) == 0) { DetectSshSoftwareVersionFree(ssh); return 1; } return 0; } /** * \test DetectSshSoftwareVersionTestParse03 is a test to make sure that we * don't return a ssh_data with an empty value specified */ int DetectSshSoftwareVersionTestParse03 (void) { DetectSshSoftwareVersionData *ssh = NULL; ssh = DetectSshSoftwareVersionParse(""); if (ssh != NULL) { DetectSshSoftwareVersionFree(ssh); return 0; } return 1; } #include "stream-tcp-reassemble.h" /** \test Send a get request in three chunks + more data. */ static int DetectSshSoftwareVersionTestDetect01(void) { int result = 0; Flow f; uint8_t sshbuf1[] = "SSH-1."; uint32_t sshlen1 = sizeof(sshbuf1) - 1; uint8_t sshbuf2[] = "10-PuTTY_2.123" ; uint32_t sshlen2 = sizeof(sshbuf2) - 1; uint8_t sshbuf3[] = "\n"; uint32_t sshlen3 = sizeof(sshbuf3) - 1; uint8_t sshbuf4[] = "whatever..."; uint32_t sshlen4 = sizeof(sshbuf4) - 1; TcpSession ssn; Packet *p = NULL; Signature *s = NULL; ThreadVars th_v; DetectEngineThreadCtx *det_ctx = NULL; AppLayerParserThreadCtx *alp_tctx = AppLayerParserThreadCtxAlloc(); memset(&th_v, 0, sizeof(th_v)); memset(&f, 0, sizeof(f)); memset(&ssn, 0, sizeof(ssn)); p = UTHBuildPacket(NULL, 0, IPPROTO_TCP); FLOW_INITIALIZE(&f); f.protoctx = (void *)&ssn; p->flow = &f; p->flowflags |= FLOW_PKT_TOSERVER; p->flowflags |= FLOW_PKT_ESTABLISHED; p->flags |= PKT_HAS_FLOW|PKT_STREAM_EST; f.alproto = ALPROTO_SSH; StreamTcpInitConfig(TRUE); DetectEngineCtx *de_ctx = DetectEngineCtxInit(); if (de_ctx == NULL) { goto end; } de_ctx->flags |= DE_QUIET; s = de_ctx->sig_list = SigInit(de_ctx,"alert ssh any any -> any any (msg:\"SSH\"; ssh.softwareversion:PuTTY_2.123; sid:1;)"); if (s == NULL) { goto end; } SigGroupBuild(de_ctx); DetectEngineThreadCtxInit(&th_v, (void *)de_ctx, (void *)&det_ctx); SCMutexLock(&f.m); int r = AppLayerParserParse(alp_tctx, &f, ALPROTO_SSH, STREAM_TOSERVER, sshbuf1, sshlen1); if (r != 0) { printf("toserver chunk 1 returned %" PRId32 ", expected 0: ", r); SCMutexUnlock(&f.m); goto end; } r = AppLayerParserParse(alp_tctx, &f, ALPROTO_SSH, STREAM_TOSERVER, sshbuf2, sshlen2); if (r != 0) { printf("toserver chunk 2 returned %" PRId32 ", expected 0: ", r); SCMutexUnlock(&f.m); goto end; } r = AppLayerParserParse(alp_tctx, &f, ALPROTO_SSH, STREAM_TOSERVER, sshbuf3, sshlen3); if (r != 0) { printf("toserver chunk 3 returned %" PRId32 ", expected 0: ", r); SCMutexUnlock(&f.m); goto end; } r = AppLayerParserParse(alp_tctx, &f, ALPROTO_SSH, STREAM_TOSERVER, sshbuf4, sshlen4); if (r != 0) { printf("toserver chunk 4 returned %" PRId32 ", expected 0: ", r); SCMutexUnlock(&f.m); goto end; } SCMutexUnlock(&f.m); SshState *ssh_state = f.alstate; if (ssh_state == NULL) { printf("no ssh state: "); goto end; } /* do detect */ SigMatchSignatures(&th_v, de_ctx, det_ctx, p); if ( !(PacketAlertCheck(p, 1))) { printf("Error, the sig should match: "); goto end; } result = 1; end: SigGroupCleanup(de_ctx); SigCleanSignatures(de_ctx); DetectEngineThreadCtxDeinit(&th_v, (void *)det_ctx); DetectEngineCtxFree(de_ctx); StreamTcpFreeConfig(TRUE); FLOW_DESTROY(&f); UTHFreePackets(&p, 1); if (alp_tctx != NULL) AppLayerParserThreadCtxFree(alp_tctx); return result; } /** \test Send a get request in three chunks + more data. */ static int DetectSshSoftwareVersionTestDetect02(void) { int result = 0; Flow f; uint8_t sshbuf1[] = "SSH-1.99-Pu"; uint32_t sshlen1 = sizeof(sshbuf1) - 1; uint8_t sshbuf2[] = "TTY_2.123" ; uint32_t sshlen2 = sizeof(sshbuf2) - 1; uint8_t sshbuf3[] = "\n"; uint32_t sshlen3 = sizeof(sshbuf3) - 1; uint8_t sshbuf4[] = "whatever..."; uint32_t sshlen4 = sizeof(sshbuf4) - 1; TcpSession ssn; Packet *p = NULL; Signature *s = NULL; ThreadVars th_v; DetectEngineThreadCtx *det_ctx = NULL; AppLayerParserThreadCtx *alp_tctx = AppLayerParserThreadCtxAlloc(); memset(&th_v, 0, sizeof(th_v)); memset(&f, 0, sizeof(f)); memset(&ssn, 0, sizeof(ssn)); p = UTHBuildPacket(NULL, 0, IPPROTO_TCP); FLOW_INITIALIZE(&f); f.protoctx = (void *)&ssn; p->flow = &f; p->flowflags |= FLOW_PKT_TOSERVER; p->flowflags |= FLOW_PKT_ESTABLISHED; p->flags |= PKT_HAS_FLOW|PKT_STREAM_EST; f.alproto = ALPROTO_SSH; StreamTcpInitConfig(TRUE); DetectEngineCtx *de_ctx = DetectEngineCtxInit(); if (de_ctx == NULL) { goto end; } de_ctx->flags |= DE_QUIET; s = de_ctx->sig_list = SigInit(de_ctx,"alert ssh any any -> any any (msg:\"SSH\"; ssh.softwareversion:PuTTY_2.123; sid:1;)"); if (s == NULL) { goto end; } SigGroupBuild(de_ctx); DetectEngineThreadCtxInit(&th_v, (void *)de_ctx, (void *)&det_ctx); SCMutexLock(&f.m); int r = AppLayerParserParse(alp_tctx, &f, ALPROTO_SSH, STREAM_TOSERVER, sshbuf1, sshlen1); if (r != 0) { printf("toserver chunk 1 returned %" PRId32 ", expected 0: ", r); SCMutexUnlock(&f.m); goto end; } r = AppLayerParserParse(alp_tctx, &f, ALPROTO_SSH, STREAM_TOSERVER, sshbuf2, sshlen2); if (r != 0) { printf("toserver chunk 2 returned %" PRId32 ", expected 0: ", r); SCMutexUnlock(&f.m); goto end; } r = AppLayerParserParse(alp_tctx, &f, ALPROTO_SSH, STREAM_TOSERVER, sshbuf3, sshlen3); if (r != 0) { printf("toserver chunk 3 returned %" PRId32 ", expected 0: ", r); SCMutexUnlock(&f.m); goto end; } r = AppLayerParserParse(alp_tctx, &f, ALPROTO_SSH, STREAM_TOSERVER, sshbuf4, sshlen4); if (r != 0) { printf("toserver chunk 4 returned %" PRId32 ", expected 0: ", r); SCMutexUnlock(&f.m); goto end; } SCMutexUnlock(&f.m); SshState *ssh_state = f.alstate; if (ssh_state == NULL) { printf("no ssh state: "); goto end; } /* do detect */ SigMatchSignatures(&th_v, de_ctx, det_ctx, p); if ( !(PacketAlertCheck(p, 1))) { printf("Error, the sig should match: "); goto end; } result = 1; end: SigGroupCleanup(de_ctx); SigCleanSignatures(de_ctx); DetectEngineThreadCtxDeinit(&th_v, (void *)det_ctx); DetectEngineCtxFree(de_ctx); StreamTcpFreeConfig(TRUE); FLOW_DESTROY(&f); UTHFreePackets(&p, 1); if (alp_tctx != NULL) AppLayerParserThreadCtxFree(alp_tctx); return result; } /** \test Send a get request in three chunks + more data. */ static int DetectSshSoftwareVersionTestDetect03(void) { int result = 0; Flow f; uint8_t sshbuf1[] = "SSH-1."; uint32_t sshlen1 = sizeof(sshbuf1) - 1; uint8_t sshbuf2[] = "7-PuTTY_2.123" ; uint32_t sshlen2 = sizeof(sshbuf2) - 1; uint8_t sshbuf3[] = "\n"; uint32_t sshlen3 = sizeof(sshbuf3) - 1; uint8_t sshbuf4[] = "whatever..."; uint32_t sshlen4 = sizeof(sshbuf4) - 1; TcpSession ssn; Packet *p = NULL; Signature *s = NULL; ThreadVars th_v; DetectEngineThreadCtx *det_ctx = NULL; AppLayerParserThreadCtx *alp_tctx = AppLayerParserThreadCtxAlloc(); memset(&th_v, 0, sizeof(th_v)); memset(&f, 0, sizeof(f)); memset(&ssn, 0, sizeof(ssn)); p = UTHBuildPacket(NULL, 0, IPPROTO_TCP); FLOW_INITIALIZE(&f); f.protoctx = (void *)&ssn; p->flow = &f; p->flowflags |= FLOW_PKT_TOSERVER; p->flowflags |= FLOW_PKT_ESTABLISHED; p->flags |= PKT_HAS_FLOW|PKT_STREAM_EST; f.alproto = ALPROTO_SSH; StreamTcpInitConfig(TRUE); DetectEngineCtx *de_ctx = DetectEngineCtxInit(); if (de_ctx == NULL) { goto end; } de_ctx->flags |= DE_QUIET; s = de_ctx->sig_list = SigInit(de_ctx,"alert ssh any any -> any any (msg:\"SSH\"; ssh.softwareversion:lalala-3.1.4; sid:1;)"); if (s == NULL) { goto end; } SigGroupBuild(de_ctx); DetectEngineThreadCtxInit(&th_v, (void *)de_ctx, (void *)&det_ctx); SCMutexLock(&f.m); int r = AppLayerParserParse(alp_tctx, &f, ALPROTO_SSH, STREAM_TOSERVER, sshbuf1, sshlen1); if (r != 0) { printf("toserver chunk 1 returned %" PRId32 ", expected 0: ", r); SCMutexUnlock(&f.m); goto end; } r = AppLayerParserParse(alp_tctx, &f, ALPROTO_SSH, STREAM_TOSERVER, sshbuf2, sshlen2); if (r != 0) { printf("toserver chunk 2 returned %" PRId32 ", expected 0: ", r); SCMutexUnlock(&f.m); goto end; } r = AppLayerParserParse(alp_tctx, &f, ALPROTO_SSH, STREAM_TOSERVER, sshbuf3, sshlen3); if (r != 0) { printf("toserver chunk 3 returned %" PRId32 ", expected 0: ", r); SCMutexUnlock(&f.m); goto end; } r = AppLayerParserParse(alp_tctx, &f, ALPROTO_SSH, STREAM_TOSERVER, sshbuf4, sshlen4); if (r != 0) { printf("toserver chunk 4 returned %" PRId32 ", expected 0: ", r); SCMutexUnlock(&f.m); goto end; } SCMutexUnlock(&f.m); SshState *ssh_state = f.alstate; if (ssh_state == NULL) { printf("no ssh state: "); goto end; } /* do detect */ SigMatchSignatures(&th_v, de_ctx, det_ctx, p); if (PacketAlertCheck(p, 1)) { printf("Error, 1.7 version is not 2 compat, so the sig should not match: "); goto end; } result = 1; end: SigGroupCleanup(de_ctx); SigCleanSignatures(de_ctx); DetectEngineThreadCtxDeinit(&th_v, (void *)det_ctx); DetectEngineCtxFree(de_ctx); StreamTcpFreeConfig(TRUE); FLOW_DESTROY(&f); UTHFreePackets(&p, 1); if (alp_tctx != NULL) AppLayerParserThreadCtxFree(alp_tctx); return result; } #endif /* UNITTESTS */ /** * \brief this function registers unit tests for DetectSshSoftwareVersion */ void DetectSshSoftwareVersionRegisterTests(void) { #ifdef UNITTESTS /* UNITTESTS */ UtRegisterTest("DetectSshSoftwareVersionTestParse01", DetectSshSoftwareVersionTestParse01, 1); UtRegisterTest("DetectSshSoftwareVersionTestParse02", DetectSshSoftwareVersionTestParse02, 1); UtRegisterTest("DetectSshSoftwareVersionTestParse03", DetectSshSoftwareVersionTestParse03, 1); UtRegisterTest("DetectSshSoftwareVersionTestDetect01", DetectSshSoftwareVersionTestDetect01, 1); UtRegisterTest("DetectSshSoftwareVersionTestDetect02", DetectSshSoftwareVersionTestDetect02, 1); UtRegisterTest("DetectSshSoftwareVersionTestDetect03", DetectSshSoftwareVersionTestDetect03, 1); #endif /* UNITTESTS */ }