From 0bd81ff838971f7884639081e2c650f5a94f0b56 Mon Sep 17 00:00:00 2001 From: Pierre Chifflier Date: Sat, 5 May 2018 16:06:54 +0200 Subject: [PATCH] Add krb5_msg_type detection keyword --- doc/userguide/rules/index.rst | 1 + doc/userguide/rules/kerberos-keywords.rst | 25 ++ rust/src/krb/detect.rs | 29 +++ rust/src/krb/mod.rs | 1 + src/Makefile.am | 1 + src/detect-engine-register.c | 2 + src/detect-engine-register.h | 2 + src/detect-krb5-msgtype.c | 272 ++++++++++++++++++++++ src/detect-krb5-msgtype.h | 33 +++ 9 files changed, 366 insertions(+) create mode 100644 doc/userguide/rules/kerberos-keywords.rst create mode 100644 rust/src/krb/detect.rs create mode 100644 src/detect-krb5-msgtype.c create mode 100644 src/detect-krb5-msgtype.h diff --git a/doc/userguide/rules/index.rst b/doc/userguide/rules/index.rst index 55f6e8aa1c..2fa4e639b8 100644 --- a/doc/userguide/rules/index.rst +++ b/doc/userguide/rules/index.rst @@ -18,6 +18,7 @@ Suricata Rules dnp3-keywords enip-keyword ftp-keywords + kerberos-keywords app-layer xbits thresholding diff --git a/doc/userguide/rules/kerberos-keywords.rst b/doc/userguide/rules/kerberos-keywords.rst new file mode 100644 index 0000000000..7e295de2da --- /dev/null +++ b/doc/userguide/rules/kerberos-keywords.rst @@ -0,0 +1,25 @@ +Kerberos Keywords +================= + +krb5_msg_type +------------- + +Kerberos message type (integer). + +Values are defined in RFC4120. Common values are + +* 10 (AS-REQ) +* 11 (AS-REP) +* 12 (TGS-REQ) +* 13 (TGS-REP) +* 14 (AP-REQ) +* 15 (AP-REP) +* 30 (ERROR) + +Syntax:: + + krb5_msg_type: + +Signature example:: + + alert krb5 any any -> any any (msg:"Kerberos 5 AS-REQ message"; krb5_msg_type:10; sid:3; rev:1;) diff --git a/rust/src/krb/detect.rs b/rust/src/krb/detect.rs new file mode 100644 index 0000000000..fe45e24be3 --- /dev/null +++ b/rust/src/krb/detect.rs @@ -0,0 +1,29 @@ +/* Copyright (C) 2018 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. + */ + +// written by Pierre Chifflier + +use libc; + +use krb::krb5::KRB5Transaction; + +#[no_mangle] +pub unsafe extern "C" fn rs_krb5_tx_get_msgtype(tx: &mut KRB5Transaction, + ptr: *mut libc::uint32_t) +{ + *ptr = tx.msg_type.0; +} diff --git a/rust/src/krb/mod.rs b/rust/src/krb/mod.rs index fea4d55906..c8be867a09 100644 --- a/rust/src/krb/mod.rs +++ b/rust/src/krb/mod.rs @@ -18,4 +18,5 @@ // written by Pierre Chifflier pub mod krb5; +pub mod detect; pub mod log; diff --git a/src/Makefile.am b/src/Makefile.am index 38aa0f82e8..7cd86bc467 100644 --- a/src/Makefile.am +++ b/src/Makefile.am @@ -213,6 +213,7 @@ detect-ipproto.c detect-ipproto.h \ detect-iprep.c detect-iprep.h \ detect-isdataat.c detect-isdataat.h \ detect-itype.c detect-itype.h \ +detect-krb5-msgtype.c detect-krb5-msgtype.h \ detect-l3proto.c detect-l3proto.h \ detect-lua.c detect-lua.h \ detect-lua-extensions.c detect-lua-extensions.h \ diff --git a/src/detect-engine-register.c b/src/detect-engine-register.c index f30c9b7d07..2537ea97e3 100644 --- a/src/detect-engine-register.c +++ b/src/detect-engine-register.c @@ -178,6 +178,7 @@ #include "detect-geoip.h" #include "detect-app-layer-protocol.h" #include "detect-template.h" +#include "detect-krb5-msgtype.h" #include "detect-target.h" #include "detect-template-buffer.h" #include "detect-bypass.h" @@ -490,6 +491,7 @@ void SigTableSetup(void) DetectBase64DecodeRegister(); DetectBase64DataRegister(); DetectTemplateRegister(); + DetectKrb5MsgTypeRegister(); DetectTargetRegister(); DetectTemplateBufferRegister(); DetectBypassRegister(); diff --git a/src/detect-engine-register.h b/src/detect-engine-register.h index 0e69c08629..cc27440737 100644 --- a/src/detect-engine-register.h +++ b/src/detect-engine-register.h @@ -197,6 +197,8 @@ enum { DETECT_BASE64_DECODE, DETECT_BASE64_DATA, + DETECT_AL_KRB5_MSGTYPE, + DETECT_TEMPLATE, DETECT_FTPDATA, DETECT_TARGET, diff --git a/src/detect-krb5-msgtype.c b/src/detect-krb5-msgtype.c new file mode 100644 index 0000000000..d1a27634ad --- /dev/null +++ b/src/detect-krb5-msgtype.c @@ -0,0 +1,272 @@ +/* Copyright (C) 2018 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 Pierre Chifflier + */ + +#include "suricata-common.h" +#include "util-unittest.h" + +#include "detect-parse.h" +#include "detect-engine.h" + +#include "detect-krb5-msgtype.h" + +#ifdef HAVE_RUST + +#include "app-layer-krb5.h" +#include "rust-krb-detect-gen.h" + +/** + * \brief Regex for parsing our keyword options + */ +#define PARSE_REGEX "^\\s*([A-z0-9\\.]+|\"[A-z0-9_\\.]+\")\\s*$" +static pcre *parse_regex; +static pcre_extra *parse_regex_study; + +/* Prototypes of functions registered in DetectKrb5MsgTypeRegister below */ +static int DetectKrb5MsgTypeMatch (ThreadVars *, DetectEngineThreadCtx *, Flow *, + uint8_t, void *, void *, const Signature *, + const SigMatchCtx *); +static int DetectKrb5MsgTypeSetup (DetectEngineCtx *, Signature *, const char *); +static void DetectKrb5MsgTypeFree (void *); +static void DetectKrb5MsgTypeRegisterTests (void); + +static int DetectEngineInspectKRB5Generic(ThreadVars *tv, + DetectEngineCtx *de_ctx, DetectEngineThreadCtx *det_ctx, + const Signature *s, const SigMatchData *smd, + Flow *f, uint8_t flags, void *alstate, + void *txv, uint64_t tx_id); + +static int g_krb5_msg_type_list_id = 0; + +/** + * \brief Registration function for krb5_msg_type: keyword + * + * This function is called once in the 'lifetime' of the engine. + */ +void DetectKrb5MsgTypeRegister(void) { + sigmatch_table[DETECT_AL_KRB5_MSGTYPE].name = "krb5_msg_type"; + sigmatch_table[DETECT_AL_KRB5_MSGTYPE].desc = "match Kerberos 5 message type"; + sigmatch_table[DETECT_AL_KRB5_MSGTYPE].url = DOC_URL DOC_VERSION "/rules/kerberos-keywords.html#krb5_msg_type"; + sigmatch_table[DETECT_AL_KRB5_MSGTYPE].Match = NULL; + sigmatch_table[DETECT_AL_KRB5_MSGTYPE].AppLayerTxMatch = DetectKrb5MsgTypeMatch; + sigmatch_table[DETECT_AL_KRB5_MSGTYPE].Setup = DetectKrb5MsgTypeSetup; + sigmatch_table[DETECT_AL_KRB5_MSGTYPE].Free = DetectKrb5MsgTypeFree; + sigmatch_table[DETECT_AL_KRB5_MSGTYPE].RegisterTests = DetectKrb5MsgTypeRegisterTests; + + DetectAppLayerInspectEngineRegister("krb5_msg_type", + ALPROTO_KRB5, SIG_FLAG_TOSERVER, 0, + DetectEngineInspectKRB5Generic); + + DetectAppLayerInspectEngineRegister("krb5_msg_type", + ALPROTO_KRB5, SIG_FLAG_TOCLIENT, 0, + DetectEngineInspectKRB5Generic); + + /* set up the PCRE for keyword parsing */ + DetectSetupParseRegexes(PARSE_REGEX, &parse_regex, &parse_regex_study); + + g_krb5_msg_type_list_id = DetectBufferTypeRegister("krb5_msg_type"); + SCLogDebug("g_krb5_msg_type_list_id %d", g_krb5_msg_type_list_id); +} + +static int DetectEngineInspectKRB5Generic(ThreadVars *tv, + DetectEngineCtx *de_ctx, DetectEngineThreadCtx *det_ctx, + const Signature *s, const SigMatchData *smd, + Flow *f, uint8_t flags, void *alstate, + void *txv, uint64_t tx_id) +{ + return DetectEngineInspectGenericList(tv, de_ctx, det_ctx, s, smd, + f, flags, alstate, txv, tx_id); +} + +/** + * \brief This function is used to match KRB5 rule option on a packet + * + * \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 with context that we will cast into DetectKrb5Data + * + * \retval 0 no match + * \retval 1 match + */ +static int DetectKrb5MsgTypeMatch (ThreadVars *t, DetectEngineThreadCtx *det_ctx, + Flow *f, uint8_t flags, void *state, + void *txv, const Signature *s, + const SigMatchCtx *ctx) +{ + uint32_t msg_type; + const DetectKrb5MsgTypeData *dd = (const DetectKrb5MsgTypeData *)ctx; + + SCEnter(); + + rs_krb5_tx_get_msgtype(txv, &msg_type); + + if (dd->msg_type == msg_type) + SCReturnInt(1); + + SCReturnInt(0); +} + +/** + * \brief This function is used to parse options passed via krb5_msgtype: keyword + * + * \param krb5str Pointer to the user provided krb5_msg_type options + * + * \retval krb5d pointer to DetectKrb5Data on success + * \retval NULL on failure + */ +static DetectKrb5MsgTypeData *DetectKrb5MsgTypeParse (const char *krb5str) +{ + DetectKrb5MsgTypeData *krb5d = NULL; + char arg1[4] = ""; +#define MAX_SUBSTRINGS 30 + int ret = 0, res = 0; + int ov[MAX_SUBSTRINGS]; + + ret = pcre_exec(parse_regex, parse_regex_study, + krb5str, strlen(krb5str), + 0, 0, ov, MAX_SUBSTRINGS); + if (ret != 2) { + SCLogError(SC_ERR_PCRE_MATCH, "parse error, ret %" PRId32 "", ret); + goto error; + } + + res = pcre_copy_substring((char *) krb5str, ov, MAX_SUBSTRINGS, 1, arg1, sizeof(arg1)); + if (res < 0) { + SCLogError(SC_ERR_PCRE_GET_SUBSTRING, "pcre_copy_substring failed"); + goto error; + } + + krb5d = SCMalloc(sizeof (DetectKrb5MsgTypeData)); + if (unlikely(krb5d == NULL)) + goto error; + krb5d->msg_type = (uint8_t)atoi(arg1); + + return krb5d; + +error: + if (krb5d) + SCFree(krb5d); + return NULL; +} + +/** + * \brief parse the options from the 'krb5_msg_type' keyword in the rule into + * the Signature data structure. + * + * \param de_ctx pointer to the Detection Engine Context + * \param s pointer to the Current Signature + * \param krb5str pointer to the user provided options + * + * \retval 0 on Success + * \retval -1 on Failure + */ +static int DetectKrb5MsgTypeSetup (DetectEngineCtx *de_ctx, Signature *s, const char *krb5str) +{ + DetectKrb5MsgTypeData *krb5d = NULL; + SigMatch *sm = NULL; + + if (DetectSignatureSetAppProto(s, ALPROTO_KRB5) != 0) + return -1; + + krb5d = DetectKrb5MsgTypeParse(krb5str); + if (krb5d == NULL) + goto error; + + sm = SigMatchAlloc(); + if (sm == NULL) + goto error; + + sm->type = DETECT_AL_KRB5_MSGTYPE; + sm->ctx = (void *)krb5d; + + s->flags |= SIG_FLAG_STATE_MATCH; + SigMatchAppendSMToList(s, sm, g_krb5_msg_type_list_id); + + return 0; + +error: + if (krb5d != NULL) + DetectKrb5MsgTypeFree(krb5d); + if (sm != NULL) + SCFree(sm); + return -1; +} + +/** + * \brief this function will free memory associated with DetectKrb5Data + * + * \param ptr pointer to DetectKrb5Data + */ +static void DetectKrb5MsgTypeFree(void *ptr) { + DetectKrb5MsgTypeData *krb5d = (DetectKrb5MsgTypeData *)ptr; + + SCFree(krb5d); +} + +#ifdef UNITTESTS + +/** + * \test description of the test + */ + +static int DetectKrb5MsgTypeParseTest01 (void) +{ + DetectKrb5MsgTypeData *krb5d = DetectKrb5MsgTypeParse("10"); + FAIL_IF_NULL(krb5d); + FAIL_IF(!(krb5d->msg_type == 10)); + DetectKrb5MsgTypeFree(krb5d); + PASS; +} + +static int DetectKrb5MsgTypeSignatureTest01 (void) +{ + DetectEngineCtx *de_ctx = DetectEngineCtxInit(); + FAIL_IF_NULL(de_ctx); + + Signature *sig = DetectEngineAppendSig(de_ctx, "alert krb5 any any -> any any (krb5_msg_type:10; sid:1; rev:1;)"); + FAIL_IF_NULL(sig); + + DetectEngineCtxFree(de_ctx); + PASS; +} + +#endif /* UNITTESTS */ + +/** + * \brief this function registers unit tests for DetectKrb5MsgType + */ +static void DetectKrb5MsgTypeRegisterTests(void) { +#ifdef UNITTESTS + UtRegisterTest("DetectKrb5MsgTypeParseTest01", DetectKrb5MsgTypeParseTest01); + UtRegisterTest("DetectKrb5MsgTypeSignatureTest01", + DetectKrb5MsgTypeSignatureTest01); +#endif /* UNITTESTS */ +} + +#else /* HAVE_RUST */ + +void DetectKrb5MsgTypeRegister(void) +{ +} + +#endif /* HAVE_RUST */ diff --git a/src/detect-krb5-msgtype.h b/src/detect-krb5-msgtype.h new file mode 100644 index 0000000000..76e8235a11 --- /dev/null +++ b/src/detect-krb5-msgtype.h @@ -0,0 +1,33 @@ +/* Copyright (C) 2015-2017 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 Pierre Chifflier + */ + +#ifndef __DETECT_KRB5_MSGTYPE_H__ +#define __DETECT_KRB5_MSGTYPE_H__ + +typedef struct DetectKrb5MsgTypeData_ { + uint8_t msg_type; +} DetectKrb5MsgTypeData; + +void DetectKrb5MsgTypeRegister(void); + +#endif /* __DETECT_KRB5_MSGTYPE_H__ */ -- 2.47.2