Skip to content

YARA · Google Cloud Threat Intelligence (GCTI)

GCTI_Cobaltstrike__Resources_Browserpivot_Bin_V1_48_To_V3_14_And_Sleeve_Browserpivot_Dll_V4_0_To_V4_X

Cobalt Strike's resources/browserpivot.bin from v1.48 to v3.14 and sleeve/browserpivot.dll from v4.0 to at least v4.4

Hack toolCobalt StrikeGoogle Cloud Threat Intelligence (GCTI)Apache License 2.0Compiles with YARA-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/browserpivot.bin from v1.48 to v3.14 and sleeve/browserpivot.dll from v4.0 to at least v4.4

Associated malware family: Cobalt Strike.

It defines 2 patterns (1 text, 1 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

cobaltstrike-resources-browserpivot-bin-v1-48-to-v3-14-and-sleeve-browserpivot-dll-v4-0-to-v4-x.yarApache License 2.0
rule GCTI_Cobaltstrike__Resources_Browserpivot_Bin_V1_48_To_V3_14_And_Sleeve_Browserpivot_Dll_V4_0_To_V4_X
{
	meta:
		description = "Cobalt Strike's resources/browserpivot.bin from v1.48 to v3.14 and sleeve/browserpivot.dll from v4.0 to at least v4.4"
		author = "gssincla@google.com"
		id = "55086544-6684-526b-914f-505a562be458"
		date = "2022-11-18"
		modified = "2022-11-19"
		reference = "https://cloud.google.com/blog/products/identity-security/making-cobalt-strike-harder-for-threat-actors-to-abuse"
		source_url = "https://github.com/chronicle/GCTI/blob/1c5fd42b1895098527fde00c2d9757edf6b303bb/YARA/CobaltStrike/CobaltStrike__Resources_Browserpivot_Bin_v1_48_to_v3_14_and_Sleeve_Browserpivot_Dll_v4_0_to_v4_x.yara#L17-L60"
		license_url = "https://github.com/chronicle/GCTI/blob/1c5fd42b1895098527fde00c2d9757edf6b303bb/LICENSE"
		hash = "12af9f5a7e9bfc49c82a33d38437e2f3f601639afbcdc9be264d3a8d84fd5539"
		logic_hash = "416554d31c105fd96aeaef508847efe2889590909c8d0025e3862e5b24078131"
		score = 75
		quality = 85
		tags = ""

	strings:
		$socket_recv = {
			FF [1-5]
			83 ?? FF 
			74 ?? 
			85 C0
			(74 | 76) ?? 
			03 ?? 
			83 ?? 02 
			72 ?? 
			80 ?? 3E FF 0A 
			75 ?? 
			80 ?? 3E FE 0D 
		}
		$fmt = "%1024[^ ] %8[^:]://%1016[^/]%7168[^ ] %1024[^ ]"

	condition:
		all of them
}

Strings (2 patterns)

IdentifierTypeValueModifiers
$socket_recvhex{ FF [1-5] 83 ?? FF 74 ?? 85 C0 (74 | 76) ?? 03 ?? 83 ?? 02 72 ?? 80 ?? 3E FF 0A 75 ?? 80 ?? 3E FE 0D }
$fmttext"%1024[^ ] %8[^:]://%1016[^/]%7168[^ ] %1024[^ ]"

Condition

all of them

In plain words (Heuristic)

  • All patterns in the rule must match.

Test this rule in your browser

Drop a file to scan it with this rule using YARA-X compiled to WebAssembly. Nothing is uploaded.

Drop a file here or click to chooseScanned locally with YARA-X. Files up to 200 MB.

Open in editor

References

Sample hashes

Hashes of samples the author lists in the rule's meta (look them up in your threat-intelligence platform).

  • 12af9f5a7e9bfc49c82a33d38437e2f3f601639afbcdc9be264d3a8d84fd5539

Licence & attribution

Author: gssincla@google.com

Source repository: Google Cloud Threat Intelligence (GCTI) @ 1c5fd42b18

Licence: Apache License 2.0 (repository licence)

Original rule

Mirrored via YARA Forge 20260927, which prefixes rule names with the source and adds normalised meta fields.

Rule id: 55086544-6684-526b-914f-505a562be458

More Cobalt Strike rules