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detect-ftpdata: match on ftp-data operation

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This keyword mathes on ftp operation STOR and RETR. It will allow
rules writer to select if the alert has to be on a put or a fetch
operation.

It is now possible to write a signature like:

  alert ftp-data any any -> any any (msg:"FTP data get firwmare"; ftdata_command:retr; sid:2; rev:1;)

to alert when a file is retrieved from a FTP server.
pull/3108/head
Eric Leblond 8 years ago committed by Victor Julien
parent b0a6934431
commit cbce2c78bd
5 changed files with 324 additions and 0 deletions
Show Stats Download Patch File Download Diff File

1
src/Makefile.am
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@ -243,6 +243,7 @@ detect-stream_size.c detect-stream_size.h \
detect-tag.c detect-tag.h \
detect-target.c detect-target.h \
detect-template.c detect-template.h \
detect-ftpdata.c detect-ftpdata.h \
detect-template-buffer.c detect-template-buffer.h \
detect-threshold.c detect-threshold.h \
detect-tls.c detect-tls.h \

1
src/detect-engine-register.h
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@ -189,6 +189,7 @@ enum {
DETECT_BASE64_DATA,
DETECT_TEMPLATE,
DETECT_FTPDATA,
DETECT_TARGET,
DETECT_AL_TEMPLATE_BUFFER,

1
src/detect-ftpbounce.c
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@ -71,6 +71,7 @@ void DetectFtpbounceRegister(void)
sigmatch_table[DETECT_FTPBOUNCE].Setup = DetectFtpbounceSetup;
sigmatch_table[DETECT_FTPBOUNCE].AppLayerTxMatch = DetectFtpbounceALMatch;
sigmatch_table[DETECT_FTPBOUNCE].RegisterTests = DetectFtpbounceRegisterTests;
sigmatch_table[DETECT_FTPBOUNCE].url = DOC_URL DOC_VERSION "/rules/ftp-keywords#ftpbounce";
sigmatch_table[DETECT_FTPBOUNCE].flags = SIGMATCH_NOOPT;
g_ftp_request_list_id = DetectBufferTypeRegister("ftp_request");

278
src/detect-ftpdata.c
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@ -0,0 +1,278 @@
/* Copyright (C) 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 Eric Leblond <eric@regit.org>
*
* Match on ftp command used to trigger a ftp data transfer
*/
#include "suricata-common.h"
#include "util-unittest.h"
#include "detect-parse.h"
#include "detect-engine.h"
#include "detect-engine-state.h"
#include "app-layer-ftp.h"
#include "detect-ftpdata.h"
/**
* \brief Regex for parsing our keyword options
*/
#define PARSE_REGEX "^\\s*(stor|retr)\\s*$"
static pcre *parse_regex;
static pcre_extra *parse_regex_study;
/* Prototypes of functions registered in DetectFtpdataRegister below */
static int DetectFtpdataMatch(ThreadVars *, DetectEngineThreadCtx *,
Flow *, uint8_t, void *, void *,
const Signature *, const SigMatchCtx *);
static int DetectFtpdataSetup (DetectEngineCtx *, Signature *, const char *);
static void DetectFtpdataFree (void *);
static void DetectFtpdataRegisterTests (void);
static int DetectEngineInspectFtpdataGeneric(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_ftpdata_buffer_id = 0;
/**
* \brief Registration function for ftpcommand: keyword
*
* This function is called once in the 'lifetime' of the engine.
*/
void DetectFtpdataRegister(void) {
/* keyword name: this is how the keyword is used in a rule */
sigmatch_table[DETECT_FTPDATA].name = "ftpdata_command";
/* description: listed in "suricata --list-keywords=all" */
sigmatch_table[DETECT_FTPDATA].desc = "match FTP command triggering a FTP data channel";
sigmatch_table[DETECT_FTPDATA].url = DOC_URL DOC_VERSION "/rules/ftp-keywords#ftpdata_command";
sigmatch_table[DETECT_FTPDATA].AppLayerTxMatch = DetectFtpdataMatch;
/* setup function is called during signature parsing, when the ftpcommand
* keyword is encountered in the rule */
sigmatch_table[DETECT_FTPDATA].Setup = DetectFtpdataSetup;
/* free function is called when the detect engine is freed. Normally at
* shutdown, but also during rule reloads. */
sigmatch_table[DETECT_FTPDATA].Free = DetectFtpdataFree;
/* registers unittests into the system */
sigmatch_table[DETECT_FTPDATA].RegisterTests = DetectFtpdataRegisterTests;
DetectAppLayerInspectEngineRegister("ftpdata_command",
ALPROTO_FTPDATA, SIG_FLAG_TOSERVER, 0,
DetectEngineInspectFtpdataGeneric);
DetectAppLayerInspectEngineRegister("ftpdata_command",
ALPROTO_FTPDATA, SIG_FLAG_TOCLIENT, 0,
DetectEngineInspectFtpdataGeneric);
g_ftpdata_buffer_id = DetectBufferTypeGetByName("ftpdata_command");
/* set up the PCRE for keyword parsing */
DetectSetupParseRegexes(PARSE_REGEX, &parse_regex, &parse_regex_study);
}
static int DetectEngineInspectFtpdataGeneric(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 check matches from the FTP App Layer Parser
*
* \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
* \retval 0 no match
* \retval 1 match
*/
static int DetectFtpdataMatch(ThreadVars *t, DetectEngineThreadCtx *det_ctx,
Flow *f, uint8_t flags,
void *state, void *txv,
const Signature *s, const SigMatchCtx *m)
{
const DetectFtpdataData *ftpcommandd = (const DetectFtpdataData *) m;
const FtpDataState *ftp_state = (const FtpDataState *)state;
if (ftp_state == NULL)
return 0;
if (ftpcommandd->command == ftp_state->command) {
/* Only match if the flow is in the good direction */
if ((flags & STREAM_TOSERVER) && (ftpcommandd->command == FTP_COMMAND_RETR)) {
return 0;
} else if ((flags & STREAM_TOCLIENT) && (ftpcommandd->command == FTP_COMMAND_STOR)) {
return 0;
}
return 1;
}
return 0;
}
/**
* \brief This function is used to parse ftpcommand options passed via ftpcommand: keyword
*
* \param ftpcommandstr Pointer to the user provided ftpcommand options
*
* \retval ftpcommandd pointer to DetectFtpdataData on success
* \retval NULL on failure
*/
static DetectFtpdataData *DetectFtpdataParse(const char *ftpcommandstr)
{
DetectFtpdataData *ftpcommandd = NULL;
char arg1[5] = "";
#define MAX_SUBSTRINGS 30
int ret = 0, res = 0;
int ov[MAX_SUBSTRINGS];
ret = pcre_exec(parse_regex, parse_regex_study,
ftpcommandstr, strlen(ftpcommandstr),
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 *) ftpcommandstr, ov, MAX_SUBSTRINGS, 1, arg1, sizeof(arg1));
if (res < 0) {
SCLogError(SC_ERR_PCRE_GET_SUBSTRING, "pcre_copy_substring failed");
goto error;
}
SCLogDebug("Arg1 \"%s\"", arg1);
ftpcommandd = SCMalloc(sizeof (DetectFtpdataData));
if (unlikely(ftpcommandd == NULL))
goto error;
if (!strcmp(arg1, "stor")) {
ftpcommandd->command = FTP_COMMAND_STOR;
} else if (!strcmp(arg1, "retr")) {
ftpcommandd->command = FTP_COMMAND_RETR;
} else {
SCLogError(SC_ERR_NOT_SUPPORTED, "Invalid command value");
goto error;
}
return ftpcommandd;
error:
if (ftpcommandd)
SCFree(ftpcommandd);
return NULL;
}
/**
* \brief parse the options from the 'ftpcommand' 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 ftpcommandstr pointer to the user provided ftpcommand options
*
* \retval 0 on Success
* \retval -1 on Failure
*/
static int DetectFtpdataSetup(DetectEngineCtx *de_ctx, Signature *s, const char *ftpcommandstr)
{
DetectFtpdataData *ftpcommandd = NULL;
SigMatch *sm = NULL;
if (DetectSignatureSetAppProto(s, ALPROTO_FTPDATA) != 0)
return -1;
ftpcommandd = DetectFtpdataParse(ftpcommandstr);
if (ftpcommandd == NULL)
goto error;
sm = SigMatchAlloc();
if (sm == NULL)
goto error;
sm->type = DETECT_FTPDATA;
sm->ctx = (void *)ftpcommandd;
s->flags |= SIG_FLAG_STATE_MATCH;
SigMatchAppendSMToList(s, sm, g_ftpdata_buffer_id);
return 0;
error:
if (ftpcommandd != NULL)
DetectFtpdataFree(ftpcommandd);
if (sm != NULL)
SCFree(sm);
return -1;
}
/**
* \brief this function will free memory associated with DetectFtpdataData
*
* \param ptr pointer to DetectFtpdataData
*/
static void DetectFtpdataFree(void *ptr) {
DetectFtpdataData *ftpcommandd = (DetectFtpdataData *)ptr;
/* do more specific cleanup here, if needed */
SCFree(ftpcommandd);
}
#if UNITTESTS
static int DetectFtpdataParseTest01(void)
{
DetectFtpdataData *ftpcommandd = DetectFtpdataParse("stor");
FAIL_IF_NULL(ftpcommandd);
FAIL_IF(!(ftpcommandd->command == FTP_COMMAND_STOR));
DetectFtpdataFree(ftpcommandd);
PASS;
}
static int DetectFtpdataSignatureTest01(void)
{
DetectEngineCtx *de_ctx = DetectEngineCtxInit();
FAIL_IF_NULL(de_ctx);
Signature *sig = DetectEngineAppendSig(de_ctx, "alert ip any any -> any any (ftpdata_command:stor; sid:1; rev:1;)");
FAIL_IF_NULL(sig);
DetectEngineCtxFree(de_ctx);
PASS;
}
#endif /* UNITTESTS */
/**
* \brief this function registers unit tests for DetectFtpdata
*/
void DetectFtpdataRegisterTests(void) {
#ifdef UNITTESTS
UtRegisterTest("DetectFtpdataParseTest01", DetectFtpdataParseTest01);
UtRegisterTest("DetectFtpdataSignatureTest01",
DetectFtpdataSignatureTest01);
#endif /* UNITTESTS */
}

43
src/detect-ftpdata.h
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@ -0,0 +1,43 @@
/* Copyright (C) 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 Eric Leblond <eric@regit.org>
*/
#ifndef __DETECT_FTPDATA_H__
#define __DETECT_FTPDATA_H__
#include "detect-engine.h"
#include "app-layer-ftp.h"
/** Per keyword data. This is set up by the DetectFtpcommandSetup() function.
* Each signature will have an instance of DetectFtpcommandData per occurence
* of the keyword.
* The structure should be considered static/readonly after initialization.
*/
typedef struct DetectFtpdataData_ {
FtpRequestCommand command;
} DetectFtpdataData;
/** \brief registers the keyword into the engine. Called from
* detect.c::SigTableSetup() */
void DetectFtpdataRegister(void);
#endif /* __DETECT_FTPDATA_H__ */
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