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YARA · CAPE Sandbox (CAPEv2)

CAPE_Stealcanti

Stealc detonation bypass

MalwareStealcCAPE 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

Stealc detonation bypass

Associated malware family: Stealc.

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
stealcanti.yarGNU General Public License v3.0
rule CAPE_Stealcanti : FILE
{
	meta:
		description = "Stealc detonation bypass"
		author = "kevoreilly"
		id = "32e5c1cf-ef57-58eb-9deb-fab0064cc676"
		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#L1-L13"
		license_url = "https://github.com/kevoreilly/CAPEv2/blob/6b15e76f28cd83fd1187da6c9aaaad2174255356/LICENSE"
		hash = "77d6f1914af6caf909fa2a246fcec05f500f79dd56e5d0d466d55924695c702d"
		logic_hash = "4132e8094b0b49a89e9f40a8b1a6abbf105bbb04e4ddf3ce739e39fc2baf0d13"
		score = 75
		quality = 70
		tags = "FILE"
		cape_options = "bp0=$anti+17,action0=skip,count=1"

	strings:
		$anti = {53 57 57 57 FF 15 [4] 8B F0 74 03 75 01 B8 E8 [4] 74 03 75 01 B8}
		$decode = {6A 03 33 D2 8B F8 59 F7 F1 8B C7 85 D2 74 04 2B C2 03 C1 6A 06 C1 E0 03 33 D2 59 F7 F1}

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

Strings (2 patterns)

IdentifierTypeValueModifiers
$antihex{53 57 57 57 FF 15 [4] 8B F0 74 03 75 01 B8 E8 [4] 74 03 75 01 B8}
$decodehex{6A 03 33 D2 8B F8 59 F7 F1 8B C7 85 D2 74 04 2B C2 03 C1 6A 06 C1 E0 03 33 D2 59 F7 F1}

Condition

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

In plain words (Heuristic)

  • The file must start with “MZ” — a Windows executable (PE).
  • All patterns in the rule must match.

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References

Sample hashes

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

  • 77d6f1914af6caf909fa2a246fcec05f500f79dd56e5d0d466d55924695c702d

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: 32e5c1cf-ef57-58eb-9deb-fab0064cc676

Metadata

cape_optionsbp0=$anti+17,action0=skip,count=1

Tags:FILE

Related rules

More Stealc rules