YARA · Google Cloud Threat Intelligence (GCTI)
GCTI_Cobaltstrike_Resources_Smbstager_Bin_V2_5_Through_V4_X
Cobalt Strike's resources/smbstager.bin signature for versions 2.5 to 4.x
- Author
- gssincla@google.com
- Date
- 2022-11-18
- Modified
- 2022-11-19
- Score / Quality
- 75 / 85
What this rule detects
Cobalt Strike's resources/smbstager.bin signature for versions 2.5 to 4.x
Associated malware family: Cobalt Strike.
It defines 3 patterns (0 text, 3 hex, 0 regex).
Summary generated from the rule's metadata and condition.
Rule source
rule GCTI_Cobaltstrike_Resources_Smbstager_Bin_V2_5_Through_V4_X
{
meta:
= "Cobalt Strike's resources/smbstager.bin signature for versions 2.5 to 4.x"
= "gssincla@google.com"
= "074b7d83-e3d8-541c-804b-2417c21f54d5"
= "2022-11-18"
= "2022-11-19"
= "https://cloud.google.com/blog/products/identity-security/making-cobalt-strike-harder-for-threat-actors-to-abuse"
= "https://github.com/chronicle/GCTI/blob/1c5fd42b1895098527fde00c2d9757edf6b303bb/YARA/CobaltStrike/CobaltStrike__Resources_Smbstager_Bin_v2_5_through_v4_x.yara#L17-L95"
= "https://github.com/chronicle/GCTI/blob/1c5fd42b1895098527fde00c2d9757edf6b303bb/LICENSE"
= "946af5a23e5403ea1caccb2e0988ec1526b375a3e919189f16491eeabc3e7d8c"
= "b0f6535069df16a64de44ca0638ec060c1ff264a7820c94710d61ca7e8474450"
= 75
= 85
= ""
strings:
$apiLocator = {
31 ??
AC
C1 ?? 0D
01 ??
38 ??
75 ??
03 [2]
3B [2]
75 ??
5?
8B ?? 24
01 ??
66 8B [2]
8B ?? 1C
01 ??
8B ?? 8B
01 ??
89 [3]
5?
5?
}
$smb = { 68 C6 96 87 52 }
$smbstart = {
6A 40
68 00 10 00 00
68 FF FF 07 00
6A 00
68 58 A4 53 E5
}
condition:
$apiLocator and $smb and $smbstart
}
Strings (3 patterns)
| Identifier | Type | Value | Modifiers |
|---|---|---|---|
| $apiLocator | hex | { 31 ?? AC C1 ?? 0D 01 ?? 38 ?? 75 ?? 03 [2] 3B [2] 75 ?? 5? 8B ?? 24 01 ?? 66 8B [2] 8B ?? 1C 01 ?? … | |
| $smb | hex | { 68 C6 96 87 52 } | |
| $smbstart | hex | { 6A 40 68 00 10 00 00 68 FF FF 07 00 6A 00 68 58 A4 53 E5 } |
Condition
$apiLocator and $smb and $smbstartIn plain words (Heuristic)
- Pattern $apiLocator must be present.
- Pattern $smb must be present.
- Pattern $smbstart must be present.
Test this rule in your browser
Drop a file to scan it with this rule using YARA-X compiled to WebAssembly. Nothing is uploaded.
Sample hashes
Hashes of samples the author lists in the rule's meta (look them up in your threat-intelligence platform).
- 946af5a23e5403ea1caccb2e0988ec1526b375a3e919189f16491eeabc3e7d8c
Licence & attribution
Author: gssincla@google.com
Source repository: Google Cloud Threat Intelligence (GCTI) @ 1c5fd42b18
Licence: Apache License 2.0 (repository licence)
Mirrored via YARA Forge 20260927, which prefixes rule names with the source and adds normalised meta fields.
Rule id: 074b7d83-e3d8-541c-804b-2417c21f54d5
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