1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
|
/* packet-credssp.c
* Routines for CredSSP (Credential Security Support Provider) packet dissection
* Graeme Lunt 2011
*
* Wireshark - Network traffic analyzer
* By Gerald Combs <gerald@wireshark.org>
* Copyright 1998 Gerald Combs
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* 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
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "config.h"
#include <glib.h>
#include <epan/packet.h>
#include <epan/asn1.h>
#include <epan/tap.h>
#include <epan/exported_pdu.h>
#include "packet-ber.h"
#include "packet-credssp.h"
#define PNAME "Credential Security Support Provider"
#define PSNAME "CredSSP"
#define PFNAME "credssp"
#define TS_PASSWORD_CREDS 1
#define TS_SMARTCARD_CREDS 2
static gint creds_type;
static gint exported_pdu_tap = -1;
/* Initialize the protocol and registered fields */
static int proto_credssp = -1;
/* List of dissectors to call for negoToken data */
static heur_dissector_list_t credssp_heur_subdissector_list;
static int hf_credssp_TSPasswordCreds = -1; /* TSPasswordCreds */
static int hf_credssp_TSSmartCardCreds = -1; /* TSSmartCardCreds */
static int hf_credssp_TSCredentials = -1; /* TSCredentials */
#include "packet-credssp-hf.c"
/* Initialize the subtree pointers */
static gint ett_credssp = -1;
#include "packet-credssp-ett.c"
#include "packet-credssp-fn.c"
/*
* Dissect CredSSP PDUs
*/
static void
dissect_credssp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *parent_tree)
{
proto_item *item=NULL;
proto_tree *tree=NULL;
if(parent_tree){
item = proto_tree_add_item(parent_tree, proto_credssp, tvb, 0, -1, ENC_NA);
tree = proto_item_add_subtree(item, ett_credssp);
}
col_set_str(pinfo->cinfo, COL_PROTOCOL, "CredSSP");
col_clear(pinfo->cinfo, COL_INFO);
creds_type = -1;
dissect_TSRequest_PDU(tvb, pinfo, tree);
}
static gboolean
dissect_credssp_heur(tvbuff_t *tvb, packet_info *pinfo, proto_tree *parent_tree, void *data _U_)
{
asn1_ctx_t asn1_ctx;
int offset = 0;
gint8 ber_class;
gboolean pc;
gint32 tag;
guint32 length;
asn1_ctx_init(&asn1_ctx, ASN1_ENC_BER, TRUE, pinfo);
/* Look for SEQUENCE, CONTEXT 0, and INTEGER 2 */
if(tvb_captured_length(tvb) > 7) {
offset = get_ber_identifier(tvb, offset, &ber_class, &pc, &tag);
if((ber_class == BER_CLASS_UNI) && (tag == BER_UNI_TAG_SEQUENCE) && (pc == TRUE)) {
offset = get_ber_length(tvb, offset, NULL, NULL);
offset = get_ber_identifier(tvb, offset, &ber_class, &pc, &tag);
if((ber_class == BER_CLASS_CON) && (tag == 0)) {
offset = get_ber_length(tvb, offset, NULL, NULL);
offset = get_ber_identifier(tvb, offset, &ber_class, &pc, &tag);
if((ber_class == BER_CLASS_UNI) && (tag == BER_UNI_TAG_INTEGER)) {
offset = get_ber_length(tvb, offset, &length, NULL);
if((length == 1) && (tvb_get_guint8(tvb, offset) == 2)) {
if (have_tap_listener(exported_pdu_tap)) {
exp_pdu_data_t *exp_pdu_data;
guint8 tags_bit_field;
tags_bit_field = EXP_PDU_TAG_IP_SRC_BIT + EXP_PDU_TAG_IP_DST_BIT + EXP_PDU_TAG_SRC_PORT_BIT+
EXP_PDU_TAG_DST_PORT_BIT + EXP_PDU_TAG_ORIG_FNO_BIT;
exp_pdu_data = load_export_pdu_tags(pinfo, "credssp", -1, &tags_bit_field, 1);
exp_pdu_data->tvb_captured_length = tvb_captured_length(tvb);
exp_pdu_data->tvb_reported_length = tvb_reported_length(tvb);
exp_pdu_data->pdu_tvb = tvb;
tap_queue_packet(exported_pdu_tap, pinfo, exp_pdu_data);
}
dissect_credssp(tvb, pinfo, parent_tree);
return TRUE;
}
}
}
}
}
return FALSE;
}
/*--- proto_register_credssp -------------------------------------------*/
void proto_register_credssp(void) {
/* List of fields */
static hf_register_info hf[] =
{
{ &hf_credssp_TSPasswordCreds,
{ "TSPasswordCreds", "credssp.TSPasswordCreds",
FT_NONE, BASE_NONE, NULL, 0,
NULL, HFILL }},
{ &hf_credssp_TSSmartCardCreds,
{ "TSSmartCardCreds", "credssp.TSSmartCardCreds",
FT_NONE, BASE_NONE, NULL, 0,
NULL, HFILL }},
{ &hf_credssp_TSCredentials,
{ "TSCredentials", "credssp.TSCredentials",
FT_NONE, BASE_NONE, NULL, 0,
NULL, HFILL }},
#include "packet-credssp-hfarr.c"
};
/* List of subtrees */
static gint *ett[] = {
&ett_credssp,
#include "packet-credssp-ettarr.c"
};
/* Register protocol */
proto_credssp = proto_register_protocol(PNAME, PSNAME, PFNAME);
register_dissector("credssp", dissect_credssp, proto_credssp);
/* Register fields and subtrees */
proto_register_field_array(proto_credssp, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
/* heuristic dissectors for any premable e.g. CredSSP before RDP */
register_heur_dissector_list("credssp", &credssp_heur_subdissector_list);
}
/*--- proto_reg_handoff_credssp --- */
void proto_reg_handoff_credssp(void) {
heur_dissector_add("ssl", dissect_credssp_heur, proto_credssp);
exported_pdu_tap = find_tap_id(EXPORT_PDU_TAP_NAME_LAYER_7);
}
|
