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YARA · CAPE Sandbox (CAPEv2)

CAPE_Stealcv2Datecheck

StealcV2 date check bypass

GenericCAPE Sandbox (CAPEv2)GNU General Public License v3.0Compiles with YARA-X
Author
kevoreilly
Date
2023-02-22
Modified
2025-09-01
Score / Quality
75 / 70

What this rule detects

StealcV2 date check bypass

Targets: Windows PE.

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

Summary generated from the rule's metadata and condition.

Rule source

Download .yar
stealcv2datecheck.yarGNU General Public License v3.0
rule CAPE_Stealcv2Datecheck : FILE
{
	meta:
		description = "StealcV2 date check bypass"
		author = "kevoreilly"
		id = "4969d005-3532-5b75-9fa9-10e09bab338e"
		date = "2023-02-22"
		modified = "2025-09-01"
		reference = "https://github.com/kevoreilly/CAPEv2"
		source_url = "https://github.com/kevoreilly/CAPEv2/blob/6b15e76f28cd83fd1187da6c9aaaad2174255356/analyzer/windows/data/yara/Stealc.yar#L45-L56"
		license_url = "https://github.com/kevoreilly/CAPEv2/blob/6b15e76f28cd83fd1187da6c9aaaad2174255356/LICENSE"
		logic_hash = "f074aceb7c111156752891acac8690c00dad7c26240fb0752cc12a9a65aa3d30"
		score = 75
		quality = 70
		tags = "FILE"
		cape_options = "patch=$date32*-1:B000,patch=$date64*-2:B00090"

	strings:
		$date32 = {F3 A5 8D 45 ?? 50 E8 [4] 59 8B F8 8B F2 8D 45 ?? 50 E8 [4] 59 3B F2 7C 08 7F 04 3B F8 76 02 B3 01 8A C3}
		$date64 = {0F 11 44 [2] 0F 11 8C [2] 00 00 00 89 8C [2] 00 00 00 48 8D 4C [2] E8 [4] 48 8B D8 48 8D 4C [2] E8 [4] 48 3B D8 0F 9F C0}

	condition:
		uint16( 0 ) == 0x5A4D and any of them
}

Strings (2 patterns)

IdentifierTypeValueModifiers
$date32hex{F3 A5 8D 45 ?? 50 E8 [4] 59 8B F8 8B F2 8D 45 ?? 50 E8 [4] 59 3B F2 7C 08 7F 04 3B F8 76 02 B3 01 8A C3}
$date64hex{0F 11 44 [2] 0F 11 8C [2] 00 00 00 89 8C [2] 00 00 00 48 8D 4C [2] E8 [4] 48 8B D8 48 8D 4C [2] E8 [4] 48 3B D8 0F 9F C0}

Condition

uint16( 0 ) == 0x5A4D and any of them

In plain words (Heuristic)

  • The file must start with “MZ” — a Windows executable (PE).
  • At least one pattern in the rule must match.

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References

Licence & attribution

Author: kevoreilly

Source repository: CAPE Sandbox (CAPEv2) @ 6b15e76f28

Licence: GNU General Public License v3.0 (repository licence)

Copyright notice: Cuckoo Sandbox is copyrighted by the Cuckoo Foundation.

Original rule

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

Rule id: 4969d005-3532-5b75-9fa9-10e09bab338e

Metadata

cape_optionspatch=$date32*-1:B000,patch=$date64*-2:B00090

Tags:FILE

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