suricata
detect-tls-ja3s-hash.c
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1 /* Copyright (C) 2019 Open Information Security Foundation
2  *
3  * You can copy, redistribute or modify this Program under the terms of
4  * the GNU General Public License version 2 as published by the Free
5  * Software Foundation.
6  *
7  * This program is distributed in the hope that it will be useful,
8  * but WITHOUT ANY WARRANTY; without even the implied warranty of
9  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
10  * GNU General Public License for more details.
11  *
12  * You should have received a copy of the GNU General Public License
13  * version 2 along with this program; if not, write to the Free Software
14  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
15  * 02110-1301, USA.
16  */
17 
18 /**
19  * \file
20  *
21  * \author Mats Klepsland <mats.klepsland@gmail.com>
22  *
23  * Implements support for ja3s.hash keyword.
24  */
25 
26 #include "suricata-common.h"
27 #include "threads.h"
28 #include "decode.h"
29 #include "detect.h"
30 
31 #include "detect-parse.h"
32 #include "detect-engine.h"
33 #include "detect-engine-mpm.h"
35 #include "detect-content.h"
36 #include "detect-pcre.h"
37 #include "detect-tls-ja3s-hash.h"
38 
39 #include "flow.h"
40 #include "flow-util.h"
41 #include "flow-var.h"
42 
43 #include "conf.h"
44 #include "conf-yaml-loader.h"
45 
46 #include "util-debug.h"
47 #include "util-spm.h"
48 #include "util-print.h"
49 #include "util-ja3.h"
50 
51 #include "stream-tcp.h"
52 
53 #include "app-layer.h"
54 #include "app-layer-ssl.h"
55 
56 #include "util-unittest.h"
57 #include "util-unittest-helper.h"
58 
59 #ifndef HAVE_JA3
60 static int DetectJA3SetupNoSupport(DetectEngineCtx *a, Signature *b, const char *c)
61 {
62  SCLogError("no JA3 support built in");
63  return -1;
64 }
65 #endif /* HAVE_JA3 */
66 
67 #ifdef HAVE_JA3
68 static int DetectTlsJa3SHashSetup(DetectEngineCtx *, Signature *, const char *);
69 static InspectionBuffer *GetData(DetectEngineThreadCtx *det_ctx,
70  const DetectEngineTransforms *transforms,
71  Flow *f, const uint8_t flow_flags,
72  void *txv, const int list_id);
73 static void DetectTlsJa3SHashSetupCallback(const DetectEngineCtx *de_ctx,
74  Signature *s);
75 static bool DetectTlsJa3SHashValidateCallback(const Signature *s,
76  const char **sigerror);
77 static int g_tls_ja3s_hash_buffer_id = 0;
78 #endif
79 
80 /**
81  * \brief Registration function for keyword: ja3s.hash
82  */
84 {
86  sigmatch_table[DETECT_AL_TLS_JA3S_HASH].desc = "sticky buffer to match the JA3S hash buffer";
87  sigmatch_table[DETECT_AL_TLS_JA3S_HASH].url = "/rules/ja3-keywords.html#ja3s-hash";
88 #ifdef HAVE_JA3
89  sigmatch_table[DETECT_AL_TLS_JA3S_HASH].Setup = DetectTlsJa3SHashSetup;
90 #else /* HAVE_JA3 */
91  sigmatch_table[DETECT_AL_TLS_JA3S_HASH].Setup = DetectJA3SetupNoSupport;
92 #endif /* HAVE_JA3 */
95 
96 #ifdef HAVE_JA3
99 
101  GetData, ALPROTO_TLS, 0);
102 
104  Ja3DetectGetHash, ALPROTO_QUIC, 1);
105 
107  DetectEngineInspectBufferGeneric, Ja3DetectGetHash);
108 
109  DetectBufferTypeSetDescriptionByName("ja3s.hash", "TLS JA3S hash");
110 
112  DetectTlsJa3SHashSetupCallback);
113 
115  DetectTlsJa3SHashValidateCallback);
116 
117  g_tls_ja3s_hash_buffer_id = DetectBufferTypeGetByName("ja3s.hash");
118 #endif /* HAVE_JA3 */
119 }
120 
121 #ifdef HAVE_JA3
122 /**
123  * \brief this function setup the ja3s.hash modifier keyword used in the rule
124  *
125  * \param de_ctx Pointer to the Detection Engine Context
126  * \param s Pointer to the Signature to which the current keyword belongs
127  * \param str Should hold an empty string always
128  *
129  * \retval 0 On success
130  * \retval -1 On failure
131  */
132 static int DetectTlsJa3SHashSetup(DetectEngineCtx *de_ctx, Signature *s, const char *str)
133 {
134  if (DetectBufferSetActiveList(de_ctx, s, g_tls_ja3s_hash_buffer_id) < 0)
135  return -1;
136 
137  if (s->alproto != ALPROTO_UNKNOWN && s->alproto != ALPROTO_TLS && s->alproto != ALPROTO_QUIC) {
138  SCLogError("rule contains conflicting protocols.");
139  return -1;
140  }
141 
142  /* try to enable JA3 */
143  SSLEnableJA3();
144 
145  /* Check if JA3 is disabled */
146  if (!RunmodeIsUnittests() && Ja3IsDisabled("rule")) {
148  SCLogError("ja3(s) support is not enabled");
149  }
150  return -2;
151  }
153 
154  return 0;
155 }
156 
157 static InspectionBuffer *GetData(DetectEngineThreadCtx *det_ctx,
158  const DetectEngineTransforms *transforms, Flow *f,
159  const uint8_t flow_flags, void *txv, const int list_id)
160 {
161  InspectionBuffer *buffer = InspectionBufferGet(det_ctx, list_id);
162  if (buffer->inspect == NULL) {
163  const SSLState *ssl_state = (SSLState *)f->alstate;
164 
165  if (ssl_state->server_connp.ja3_hash == NULL) {
166  return NULL;
167  }
168 
169  const uint32_t data_len = strlen(ssl_state->server_connp.ja3_hash);
170  const uint8_t *data = (uint8_t *)ssl_state->server_connp.ja3_hash;
171 
172  InspectionBufferSetup(det_ctx, list_id, buffer, data, data_len);
173  InspectionBufferApplyTransforms(buffer, transforms);
174  }
175 
176  return buffer;
177 }
178 
179 static bool DetectTlsJa3SHashValidateCallback(const Signature *s,
180  const char **sigerror)
181 {
182  for (uint32_t x = 0; x < s->init_data->buffer_index; x++) {
183  if (s->init_data->buffers[x].id != (uint32_t)g_tls_ja3s_hash_buffer_id)
184  continue;
185  const SigMatch *sm = s->init_data->buffers[x].head;
186  for (; sm != NULL; sm = sm->next) {
187  if (sm->type != DETECT_CONTENT)
188  continue;
189 
190  const DetectContentData *cd = (DetectContentData *)sm->ctx;
191 
192  if (cd->flags & DETECT_CONTENT_NOCASE) {
193  *sigerror = "ja3s.hash should not be used together with "
194  "nocase, since the rule is automatically "
195  "lowercased anyway which makes nocase redundant.";
196  SCLogWarning("rule %u: %s", s->id, *sigerror);
197  }
198 
199  if (cd->content_len == SC_MD5_HEX_LEN)
200  return true;
201 
202  *sigerror = "Invalid length of the specified JA3S hash (should "
203  "be 32 characters long). This rule will therefore "
204  "never match.";
205  SCLogError("rule %u: %s", s->id, *sigerror);
206  return false;
207  }
208  }
209  return true;
210 }
211 
212 static void DetectTlsJa3SHashSetupCallback(const DetectEngineCtx *de_ctx,
213  Signature *s)
214 {
215  for (uint32_t x = 0; x < s->init_data->buffer_index; x++) {
216  if (s->init_data->buffers[x].id != (uint32_t)g_tls_ja3s_hash_buffer_id)
217  continue;
218  SigMatch *sm = s->init_data->buffers[x].head;
219  for (; sm != NULL; sm = sm->next) {
220  if (sm->type != DETECT_CONTENT)
221  continue;
222 
224 
225  bool changed = false;
226  uint32_t u;
227  for (u = 0; u < cd->content_len; u++) {
228  if (isupper(cd->content[u])) {
229  cd->content[u] = u8_tolower(cd->content[u]);
230  changed = true;
231  }
232  }
233 
234  /* recreate the context if changes were made */
235  if (changed) {
236  SpmDestroyCtx(cd->spm_ctx);
237  cd->spm_ctx =
239  }
240  }
241  }
242 }
243 #endif
DETECT_CONTENT_NOCASE
#define DETECT_CONTENT_NOCASE
Definition: detect-content.h:29
SigTableElmt_::url
const char * url
Definition: detect.h:1304
SignatureInitDataBuffer_::head
SigMatch * head
Definition: detect.h:535
SSLState_
SSLv[2.0|3.[0|1|2|3]] state structure.
Definition: app-layer-ssl.h:296
detect-content.h
detect-engine.h
SIGMATCH_INFO_STICKY_BUFFER
#define SIGMATCH_INFO_STICKY_BUFFER
Definition: detect.h:1509
SigTableElmt_::desc
const char * desc
Definition: detect.h:1303
DetectTlsJa3SHashRegister
void DetectTlsJa3SHashRegister(void)
Registration function for keyword: ja3s.hash.
Definition: detect-tls-ja3s-hash.c:83
sigmatch_table
SigTableElmt * sigmatch_table
Definition: detect-parse.c:127
DetectEngineInspectBufferGeneric
uint8_t DetectEngineInspectBufferGeneric(DetectEngineCtx *de_ctx, DetectEngineThreadCtx *det_ctx, const DetectEngineAppInspectionEngine *engine, const Signature *s, Flow *f, uint8_t flags, void *alstate, void *txv, uint64_t tx_id)
Do the content inspection & validation for a signature.
Definition: detect-engine.c:2140
flow-util.h
SigTableElmt_::name
const char * name
Definition: detect.h:1301
stream-tcp.h
DetectEngineTransforms
Definition: detect.h:408
DETECT_CONTENT
@ DETECT_CONTENT
Definition: detect-engine-register.h:70
ALPROTO_TLS
@ ALPROTO_TLS
Definition: app-layer-protos.h:33
Signature_::alproto
AppProto alproto
Definition: detect.h:606
SSLState_::server_connp
SSLStateConnp server_connp
Definition: app-layer-ssl.h:315
ALPROTO_QUIC
@ ALPROTO_QUIC
Definition: app-layer-protos.h:51
DetectBufferSetActiveList
int DetectBufferSetActiveList(DetectEngineCtx *de_ctx, Signature *s, const int list)
Definition: detect-engine.c:1354
SSLStateConnp_::ja3_hash
char * ja3_hash
Definition: app-layer-ssl.h:278
InspectionBuffer
Definition: detect.h:373
threads.h
Flow_
Flow data structure.
Definition: flow.h:360
DetectBufferTypeRegisterSetupCallback
void DetectBufferTypeRegisterSetupCallback(const char *name, void(*SetupCallback)(const DetectEngineCtx *, Signature *))
Definition: detect-engine.c:1285
SigTableElmt_::flags
uint16_t flags
Definition: detect.h:1295
DetectEngineCtx_
main detection engine ctx
Definition: detect.h:841
u8_tolower
#define u8_tolower(c)
Definition: suricata-common.h:436
util-ja3.h
SignatureInitData_::init_flags
uint32_t init_flags
Definition: detect.h:553
DetectContentData_
Definition: detect-content.h:93
SIG_FLAG_TOCLIENT
#define SIG_FLAG_TOCLIENT
Definition: detect.h:268
SigTableElmt_::Setup
int(* Setup)(DetectEngineCtx *, Signature *, const char *)
Definition: detect.h:1286
detect-pcre.h
detect-engine-prefilter.h
util-unittest.h
InspectionBufferGet
InspectionBuffer * InspectionBufferGet(DetectEngineThreadCtx *det_ctx, const int list_id)
Definition: detect-engine.c:1498
util-unittest-helper.h
DetectBufferTypeGetByName
int DetectBufferTypeGetByName(const char *name)
Definition: detect-engine.c:1091
Ja3IsDisabled
int Ja3IsDisabled(const char *type)
Definition: util-ja3.c:325
decode.h
util-debug.h
DetectBufferTypeRegisterValidateCallback
void DetectBufferTypeRegisterValidateCallback(const char *name, bool(*ValidateCallback)(const Signature *, const char **sigerror))
Definition: detect-engine.c:1303
de_ctx
DetectEngineCtx * de_ctx
Definition: fuzz_siginit.c:17
DetectEngineThreadCtx_
Definition: detect.h:1090
util-print.h
detect-engine-mpm.h
detect.h
SigMatch_::next
struct SigMatch_ * next
Definition: detect.h:353
DETECT_AL_TLS_JA3S_HASH
@ DETECT_AL_TLS_JA3S_HASH
Definition: detect-engine-register.h:260
PrefilterGenericMpmRegister
int PrefilterGenericMpmRegister(DetectEngineCtx *de_ctx, SigGroupHead *sgh, MpmCtx *mpm_ctx, const DetectBufferMpmRegistry *mpm_reg, int list_id)
Definition: detect-engine-prefilter.c:750
SCLogWarning
#define SCLogWarning(...)
Macro used to log WARNING messages.
Definition: util-debug.h:249
DetectAppLayerMpmRegister
void DetectAppLayerMpmRegister(const char *name, int direction, int priority, PrefilterRegisterFunc PrefilterRegister, InspectionBufferGetDataPtr GetData, AppProto alproto, int tx_min_progress)
register an app layer keyword for mpm
Definition: detect-engine-mpm.c:151
SigMatch_::ctx
SigMatchCtx * ctx
Definition: detect.h:352
conf-yaml-loader.h
conf.h
DetectContentData_::flags
uint32_t flags
Definition: detect-content.h:104
SSLEnableJA3
void SSLEnableJA3(void)
if not explicitly disabled in config, enable ja3 support
Definition: app-layer-ssl.c:3360
Signature_::init_data
SignatureInitData * init_data
Definition: detect.h:670
RunmodeIsUnittests
int RunmodeIsUnittests(void)
Definition: suricata.c:252
SIG_FLAG_INIT_JA
#define SIG_FLAG_INIT_JA
Definition: detect.h:297
SigMatchSilentErrorEnabled
bool SigMatchSilentErrorEnabled(const DetectEngineCtx *de_ctx, const enum DetectKeywordId id)
Definition: detect-parse.c:378
suricata-common.h
SigMatch_::type
uint16_t type
Definition: detect.h:350
InspectionBufferApplyTransforms
void InspectionBufferApplyTransforms(InspectionBuffer *buffer, const DetectEngineTransforms *transforms)
Definition: detect-engine.c:1697
util-spm.h
DetectContentData_::content
uint8_t * content
Definition: detect-content.h:94
DetectContentData_::spm_ctx
SpmCtx * spm_ctx
Definition: detect-content.h:111
SignatureInitData_::buffers
SignatureInitDataBuffer * buffers
Definition: detect.h:591
InspectionBuffer::inspect
const uint8_t * inspect
Definition: detect.h:374
str
#define str(s)
Definition: suricata-common.h:291
SCLogError
#define SCLogError(...)
Macro used to log ERROR messages.
Definition: util-debug.h:261
InspectionBufferSetup
void InspectionBufferSetup(DetectEngineThreadCtx *det_ctx, const int list_id, InspectionBuffer *buffer, const uint8_t *data, const uint32_t data_len)
setup the buffer with our initial data
Definition: detect-engine.c:1593
Flow_::alstate
void * alstate
Definition: flow.h:485
Signature_::id
uint32_t id
Definition: detect.h:636
detect-tls-ja3s-hash.h
detect-parse.h
SignatureInitDataBuffer_::id
uint32_t id
Definition: detect.h:528
Signature_
Signature container.
Definition: detect.h:601
SigMatch_
a single match condition for a signature
Definition: detect.h:349
ALPROTO_UNKNOWN
@ ALPROTO_UNKNOWN
Definition: app-layer-protos.h:29
DetectContentData_::content_len
uint16_t content_len
Definition: detect-content.h:95
SIGMATCH_NOOPT
#define SIGMATCH_NOOPT
Definition: detect.h:1485
DetectAppLayerInspectEngineRegister
void DetectAppLayerInspectEngineRegister(const char *name, AppProto alproto, uint32_t dir, int progress, InspectEngineFuncPtr Callback, InspectionBufferGetDataPtr GetData)
Registers an app inspection engine.
Definition: detect-engine.c:238
DetectEngineCtx_::spm_global_thread_ctx
SpmGlobalThreadCtx * spm_global_thread_ctx
Definition: detect.h:892
DetectBufferTypeSetDescriptionByName
void DetectBufferTypeSetDescriptionByName(const char *name, const char *desc)
Definition: detect-engine.c:1188
flow.h
SpmDestroyCtx
void SpmDestroyCtx(SpmCtx *ctx)
Definition: util-spm.c:183
SignatureInitData_::buffer_index
uint32_t buffer_index
Definition: detect.h:592
flow-var.h
SpmInitCtx
SpmCtx * SpmInitCtx(const uint8_t *needle, uint16_t needle_len, int nocase, SpmGlobalThreadCtx *global_thread_ctx)
Definition: util-spm.c:173
app-layer-ssl.h
app-layer.h