suricata
detect-ja4-hash.c
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1 /* Copyright (C) 2023 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 Sascha Steinbiss <sascha@steinbiss.name>
22  *
23  * Implements support for ja4.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-buffer.h"
34 #include "detect-engine-mpm.h"
35 #include "detect-engine-prefilter.h"
36 #include "detect-ja4-hash.h"
37 
38 #include "app-layer-ssl.h"
39 
40 #ifndef HAVE_JA4
41 static int DetectJA4SetupNoSupport(DetectEngineCtx *a, Signature *b, const char *c)
42 {
43  SCLogError("no JA4 support built in");
44  return -1;
45 }
46 #endif /* HAVE_JA4 */
47 
48 #ifdef HAVE_JA4
49 static int DetectJa4HashSetup(DetectEngineCtx *, Signature *, const char *);
50 static InspectionBuffer *GetData(DetectEngineThreadCtx *det_ctx,
51  const DetectEngineTransforms *transforms, Flow *f, const uint8_t flow_flags, void *txv,
52  const int list_id);
53 int Ja4IsDisabled(const char *type);
54 static InspectionBuffer *Ja4DetectGetHash(DetectEngineThreadCtx *det_ctx,
55  const DetectEngineTransforms *transforms, Flow *_f, const uint8_t _flow_flags, void *txv,
56  const int list_id);
57 #ifdef UNITTESTS
58 static void DetectJa4RegisterTests(void);
59 #endif
60 
61 static int g_ja4_hash_buffer_id = 0;
62 #endif
63 
64 /**
65  * \brief Registration function for keyword: ja4.hash
66  */
67 void DetectJa4HashRegister(void)
68 {
69  sigmatch_table[DETECT_JA4_HASH].name = "ja4.hash";
70  sigmatch_table[DETECT_JA4_HASH].alias = "ja4_hash";
71  sigmatch_table[DETECT_JA4_HASH].desc = "sticky buffer to match the JA4 hash buffer";
72  sigmatch_table[DETECT_JA4_HASH].url = "/rules/ja4-keywords.html#ja4-hash";
73 #ifdef HAVE_JA4
74  sigmatch_table[DETECT_JA4_HASH].Setup = DetectJa4HashSetup;
75 #ifdef UNITTESTS
76  sigmatch_table[DETECT_JA4_HASH].RegisterTests = DetectJa4RegisterTests;
77 #endif
78 #else /* HAVE_JA4 */
79  sigmatch_table[DETECT_JA4_HASH].Setup = DetectJA4SetupNoSupport;
80 #endif /* HAVE_JA4 */
81  sigmatch_table[DETECT_JA4_HASH].flags |= SIGMATCH_NOOPT;
82  sigmatch_table[DETECT_JA4_HASH].flags |= SIGMATCH_INFO_STICKY_BUFFER;
83 
84 #ifdef HAVE_JA4
85  DetectAppLayerInspectEngineRegister("ja4.hash", ALPROTO_TLS, SIG_FLAG_TOSERVER,
86  TLS_STATE_CLIENT_HELLO_DONE, DetectEngineInspectBufferGeneric, GetData);
87 
88  DetectAppLayerMpmRegister("ja4.hash", SIG_FLAG_TOSERVER, 2, PrefilterGenericMpmRegister,
89  GetData, ALPROTO_TLS, TLS_STATE_CLIENT_HELLO_DONE);
90 
91  DetectAppLayerMpmRegister("ja4.hash", SIG_FLAG_TOSERVER, 2, PrefilterGenericMpmRegister,
92  Ja4DetectGetHash, ALPROTO_QUIC, 1);
93 
94  DetectAppLayerInspectEngineRegister("ja4.hash", ALPROTO_QUIC, SIG_FLAG_TOSERVER, 1,
95  DetectEngineInspectBufferGeneric, Ja4DetectGetHash);
96 
97  DetectBufferTypeSetDescriptionByName("ja4.hash", "TLS JA4 hash");
98 
99  g_ja4_hash_buffer_id = DetectBufferTypeGetByName("ja4.hash");
100 #endif /* HAVE_JA4 */
101 }
102 
103 #ifdef HAVE_JA4
104 /**
105  * \brief this function setup the ja4.hash modifier keyword used in the rule
106  *
107  * \param de_ctx Pointer to the Detection Engine Context
108  * \param s Pointer to the Signature to which the current keyword belongs
109  * \param str Should hold an empty string always
110  *
111  * \retval 0 On success
112  * \retval -1 On failure
113  */
114 static int DetectJa4HashSetup(DetectEngineCtx *de_ctx, Signature *s, const char *str)
115 {
116  if (SCDetectBufferSetActiveList(de_ctx, s, g_ja4_hash_buffer_id) < 0)
117  return -1;
118 
119  AppProto alprotos[] = { ALPROTO_TLS, ALPROTO_QUIC, ALPROTO_UNKNOWN };
120  if (DetectSignatureSetMultiAppProto(s, alprotos) < 0) {
121  SCLogError("rule contains conflicting protocols.");
122  return -1;
123  }
124 
125  /* try to enable JA4 */
126  SSLEnableJA4();
127 
128  /* check if JA4 enabling had an effect */
129  if (!RunmodeIsUnittests() && !SSLJA4IsEnabled()) {
130  if (!SigMatchSilentErrorEnabled(de_ctx, DETECT_JA4_HASH)) {
131  SCLogError("JA4 support is not enabled");
132  }
133  return -2;
134  }
135 
136  return 0;
137 }
138 
139 static InspectionBuffer *GetData(DetectEngineThreadCtx *det_ctx,
140  const DetectEngineTransforms *transforms, Flow *f, const uint8_t flow_flags, void *txv,
141  const int list_id)
142 {
143  InspectionBuffer *buffer = InspectionBufferGet(det_ctx, list_id);
144  if (buffer->inspect == NULL) {
145  const SSLState *ssl_state = (SSLState *)f->alstate;
146 
147  if (ssl_state->client_connp.hs == NULL) {
148  return NULL;
149  }
150 
151  uint8_t data[JA4_HEX_LEN];
152  SCJA4GetHash(ssl_state->client_connp.hs, (uint8_t(*)[JA4_HEX_LEN])data);
153 
154  InspectionBufferSetup(det_ctx, list_id, buffer, data, 0);
155  InspectionBufferCopy(buffer, data, JA4_HEX_LEN);
156  InspectionBufferApplyTransforms(det_ctx, buffer, transforms);
157  }
158 
159  return buffer;
160 }
161 
162 static InspectionBuffer *Ja4DetectGetHash(DetectEngineThreadCtx *det_ctx,
163  const DetectEngineTransforms *transforms, Flow *_f, const uint8_t _flow_flags, void *txv,
164  const int list_id)
165 {
166  InspectionBuffer *buffer = InspectionBufferGet(det_ctx, list_id);
167  if (buffer->inspect == NULL) {
168  uint32_t b_len = 0;
169  const uint8_t *b = NULL;
170 
171  if (SCQuicTxGetJa4(txv, &b, &b_len) != 1)
172  return NULL;
173  if (b == NULL || b_len == 0)
174  return NULL;
175 
176  InspectionBufferSetup(det_ctx, list_id, buffer, NULL, 0);
177  InspectionBufferCopy(buffer, (uint8_t *)b, JA4_HEX_LEN);
178  InspectionBufferApplyTransforms(det_ctx, buffer, transforms);
179  }
180  return buffer;
181 }
182 
183 #ifdef UNITTESTS
184 static int DetectJa4TestParse01(void)
185 {
186  DetectEngineCtx *de_ctx = DetectEngineCtxInit();
187 
188  // invalid tests
189  Signature *s =
190  SigInit(de_ctx, "alert ip any any -> any any (sid: 1; file.data; content: \"toto\"; "
191  "ja4.hash; content: \"q13d0310h3_55b375c5d22e_cd85d2d88918\";)");
192  // cannot have file.data with ja4.hash (quic or tls)
193  FAIL_IF_NOT_NULL(s);
194  s = SigInit(de_ctx, "alert ip any any -> any any (sid: 1; "
195  "ja4.hash; content: \"q13d0310h3_55b375c5d22e_cd85d2d88918\"; file.data; "
196  "content: \"toto\";)");
197  // cannot have file.data with ja4.hash (quic or tls)
198  FAIL_IF_NOT_NULL(s);
199  s = SigInit(de_ctx, "alert smb any any -> any any (sid: 1; "
200  "ja4.hash; content: \"q13d0310h3_55b375c5d22e_cd85d2d88918\";)");
201  // cannot have alproto=smb with ja4.hash (quic or tls)
202  FAIL_IF_NOT_NULL(s);
203  s = SigInit(de_ctx, "alert ip any any -> any any (sid: 1; "
204  "ja4.hash; content: \"q13d0310h3_55b375c5d22e_cd85d2d88918\"; smb.share; "
205  "content:\"toto\";)");
206  // cannot have a smb keyword with ja4.hash (quic or tls)
207  FAIL_IF_NOT_NULL(s);
208  s = SigInit(de_ctx, "alert ip any any -> any any (sid: 1; "
209  "smb.share; content:\"toto\"; ja4.hash; content: "
210  "\"q13d0310h3_55b375c5d22e_cd85d2d88918\";)");
211  // cannot have a smb keyword with ja4.hash (quic or tls)
212  FAIL_IF_NOT_NULL(s);
213 
214  // valid tests
215  s = DetectEngineAppendSig(de_ctx,
216  "alert ip any any -> any any (sid: 1; "
217  "ja4.hash; content: \"q13d0310h3_55b375c5d22e_cd85d2d88918\";)");
218  // just ja4.hash any proto
219  FAIL_IF_NULL(s);
220  s = DetectEngineAppendSig(de_ctx,
221  "alert quic any any -> any any (sid: 2; "
222  "ja4.hash; content: \"q13d0310h3_55b375c5d22e_cd85d2d88918\";)");
223  // just ja4.hash only quic
224  FAIL_IF_NULL(s);
225  s = DetectEngineAppendSig(de_ctx,
226  "alert tls any any -> any any (sid: 3; "
227  "ja4.hash; content: \"q13d0310h3_55b375c5d22e_cd85d2d88918\";)");
228  // just ja4.hash only tls
229  FAIL_IF_NULL(s);
230  s = DetectEngineAppendSig(de_ctx,
231  "alert ip any any -> any any (sid: 4; "
232  "ja4.hash; content: \"q13d0310h3_55b375c5d22e_cd85d2d88918\"; "
233  "quic.version; content:\"|00|\";)");
234  // ja4.hash and a quic keyword
235  FAIL_IF_NULL(s);
236  DetectEngineCtxFree(de_ctx);
237  PASS;
238 }
239 
240 static void DetectJa4RegisterTests(void)
241 {
242  UtRegisterTest("DetectJa4TestParse01", DetectJa4TestParse01);
243 }
244 #endif
245 
246 #endif // HAVE_JA4
InspectionBufferApplyTransforms
void InspectionBufferApplyTransforms(DetectEngineThreadCtx *det_ctx, InspectionBuffer *buffer, const DetectEngineTransforms *transforms)
Definition: detect-engine-inspect-buffer.c:128
SigTableElmt_::url
const char * url
Definition: detect.h:1462
SSLState_
SSLv[2.0|3.[0|1|2|3]] state structure.
Definition: app-layer-ssl.h:227
detect-engine.h
FAIL_IF_NULL
#define FAIL_IF_NULL(expr)
Fail a test if expression evaluates to NULL.
Definition: util-unittest.h:89
SIGMATCH_INFO_STICKY_BUFFER
#define SIGMATCH_INFO_STICKY_BUFFER
Definition: detect.h:1676
SigTableElmt_::desc
const char * desc
Definition: detect.h:1461
sigmatch_table
SigTableElmt * sigmatch_table
Definition: detect-parse.c:79
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:2059
SigTableElmt_::name
const char * name
Definition: detect.h:1459
InspectionBufferCopy
void InspectionBufferCopy(InspectionBuffer *buffer, uint8_t *buf, uint32_t buf_len)
Definition: detect-engine-inspect-buffer.c:246
DetectEngineTransforms
Definition: detect.h:391
UtRegisterTest
void UtRegisterTest(const char *name, int(*TestFn)(void))
Register unit test.
Definition: util-unittest.c:103
SSLState_::client_connp
SSLStateConnp client_connp
Definition: app-layer-ssl.h:248
DetectSignatureSetMultiAppProto
int DetectSignatureSetMultiAppProto(Signature *s, const AppProto *alprotos)
this function is used to set multiple possible app-layer protos
Definition: detect-parse.c:2151
ALPROTO_TLS
@ ALPROTO_TLS
Definition: app-layer-protos.h:39
SSLEnableJA4
void SSLEnableJA4(void)
if not explicitly disabled in config, enable ja4 support
Definition: app-layer-ssl.c:3336
AppProto
uint16_t AppProto
Definition: app-layer-protos.h:86
ALPROTO_QUIC
@ ALPROTO_QUIC
Definition: app-layer-protos.h:57
InspectionBuffer
Definition: detect-engine-inspect-buffer.h:34
threads.h
Flow_
Flow data structure.
Definition: flow.h:356
SigTableElmt_::flags
uint16_t flags
Definition: detect.h:1450
DetectEngineCtx_
main detection engine ctx
Definition: detect.h:932
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-inspect-buffer.c:190
DetectEngineCtxFree
void DetectEngineCtxFree(DetectEngineCtx *)
Free a DetectEngineCtx::
Definition: detect-engine.c:2643
SCDetectBufferSetActiveList
int SCDetectBufferSetActiveList(DetectEngineCtx *de_ctx, Signature *s, const int list)
Definition: detect-engine-buffer.c:29
DetectEngineAppendSig
Signature * DetectEngineAppendSig(DetectEngineCtx *, const char *)
Parse and append a Signature into the Detection Engine Context signature list.
Definition: detect-parse.c:3437
InspectionBufferGet
InspectionBuffer * InspectionBufferGet(DetectEngineThreadCtx *det_ctx, const int list_id)
Definition: detect-engine-inspect-buffer.c:56
SigTableElmt_::Setup
int(* Setup)(DetectEngineCtx *, Signature *, const char *)
Definition: detect.h:1441
detect-engine-prefilter.h
DetectBufferTypeGetByName
int DetectBufferTypeGetByName(const char *name)
Definition: detect-engine.c:1279
SIG_FLAG_TOSERVER
#define SIG_FLAG_TOSERVER
Definition: detect.h:271
decode.h
FAIL_IF_NOT_NULL
#define FAIL_IF_NOT_NULL(expr)
Fail a test if expression evaluates to non-NULL.
Definition: util-unittest.h:96
PASS
#define PASS
Pass the test.
Definition: util-unittest.h:105
de_ctx
DetectEngineCtx * de_ctx
Definition: fuzz_siginit.c:18
DetectEngineThreadCtx_
Definition: detect.h:1244
TLS_STATE_CLIENT_HELLO_DONE
@ TLS_STATE_CLIENT_HELLO_DONE
Definition: app-layer-ssl.h:79
detect-engine-mpm.h
detect.h
detect-ja4-hash.h
PrefilterGenericMpmRegister
int PrefilterGenericMpmRegister(DetectEngineCtx *de_ctx, SigGroupHead *sgh, MpmCtx *mpm_ctx, const DetectBufferMpmRegistry *mpm_reg, int list_id)
Definition: detect-engine-prefilter.c:1584
SigInit
Signature * SigInit(DetectEngineCtx *de_ctx, const char *sigstr)
Parses a signature and adds it to the Detection Engine Context.
Definition: detect-parse.c:3095
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:154
type
uint16_t type
Definition: decode-vlan.c:106
RunmodeIsUnittests
int RunmodeIsUnittests(void)
Definition: suricata.c:270
SigMatchSilentErrorEnabled
bool SigMatchSilentErrorEnabled(const DetectEngineCtx *de_ctx, const enum DetectKeywordId id)
Definition: detect-parse.c:330
SigTableElmt_::alias
const char * alias
Definition: detect.h:1460
suricata-common.h
detect-engine-buffer.h
InspectionBuffer::inspect
const uint8_t * inspect
Definition: detect-engine-inspect-buffer.h:35
str
#define str(s)
Definition: suricata-common.h:308
DETECT_JA4_HASH
@ DETECT_JA4_HASH
Definition: detect-engine-register.h:318
SCLogError
#define SCLogError(...)
Macro used to log ERROR messages.
Definition: util-debug.h:267
Flow_::alstate
void * alstate
Definition: flow.h:479
detect-parse.h
Signature_
Signature container.
Definition: detect.h:668
SSLJA4IsEnabled
bool SSLJA4IsEnabled(void)
return whether ja4 is effectively enabled
Definition: app-layer-ssl.c:3369
ALPROTO_UNKNOWN
@ ALPROTO_UNKNOWN
Definition: app-layer-protos.h:29
DetectEngineCtxInit
DetectEngineCtx * DetectEngineCtxInit(void)
Definition: detect-engine.c:2604
SSLStateConnp_::hs
HandshakeParams * hs
Definition: app-layer-ssl.h:211
SIGMATCH_NOOPT
#define SIGMATCH_NOOPT
Definition: detect.h:1651
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:272
DetectBufferTypeSetDescriptionByName
void DetectBufferTypeSetDescriptionByName(const char *name, const char *desc)
Definition: detect-engine.c:1376
DetectJa4HashRegister
void DetectJa4HashRegister(void)
Registration function for keyword: ja4.hash.
Definition: detect-ja4-hash.c:67
app-layer-ssl.h
SigTableElmt_::RegisterTests
void(* RegisterTests)(void)
Definition: detect.h:1448