YARA · CAPE Sandbox (CAPEv2)

CAPE_Icedidsyscallwritemem

IcedID 'syscall' packer bypass - direct write variant

Suspicious / huntingIcedidCAPE Sandbox (CAPEv2)GNU General Public License v3.0Compiles with YARA-X

Author: kevoreilly
Date: 2021-03-30
Modified: 2023-11-28
Score / Quality: 75 / 70

What this rule detects

IcedID 'syscall' packer bypass - direct write variant

Associated malware family: Icedid.

Targets: Windows PE.

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

Summary generated from the rule's metadata and condition.

Rule source

Download .yar

icedidsyscallwritemem.yarGNU General Public License v3.0

rule CAPE_Icedidsyscallwritemem : FILE
{
	meta:
		description = "IcedID 'syscall' packer bypass - direct write variant"
		author = "kevoreilly"
		id = "67935058-4191-587f-ad19-497defd0eef1"
		date = "2021-03-30"
		modified = "2023-11-28"
		reference = "https://github.com/kevoreilly/CAPEv2"
		source_url = "https://github.com/kevoreilly/CAPEv2/blob/6b15e76f28cd83fd1187da6c9aaaad2174255356/analyzer/windows/data/yara/IcedID.yar#L1-L13"
		license_url = "https://github.com/kevoreilly/CAPEv2/blob/6b15e76f28cd83fd1187da6c9aaaad2174255356/LICENSE"
		logic_hash = "6b068106b038e9efeb9057cadf314d400c1ada1a1cc70336d3272da3a212c993"
		score = 75
		quality = 70
		tags = "FILE"
		cape_options = "bp0=$tokencheck+9,action0=jmp,count=0"
		packed = "28075ecae5e224c06e250f2c949c826b81844bca421e9158a7a9e965a29ef894"
		packed = "045dff9f14a03225df55997cb2ca74ff60ecaf317b9e033ea93386785db84161"

	strings:
		$tokencheck = {39 5D ?? 75 06 83 7D ?? 03 74 05 BB 01 00 00 00 41 89 1C ?? 48 8B 4D ?? 41 FF D?}

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

Strings (1 patterns)

Identifier	Type	Value	Modifiers
$tokencheck	hex	{39 5D ?? 75 06 83 7D ?? 03 74 05 BB 01 00 00 00 41 89 1C ?? 48 8B 4D ?? 41 FF D?}

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.

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

https://github.com/kevoreilly/CAPEv2

Licence & attribution

Author: kevoreilly

Source repository: CAPE Sandbox (CAPEv2) @ 6b15e76f28

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

Original rule

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

Rule id: 67935058-4191-587f-ad19-497defd0eef1

Metadata

cape_options	bp0=$tokencheck+9,action0=jmp,count=0
packed	28075ecae5e224c06e250f2c949c826b81844bca421e9158a7a9e965a29ef894
packed	045dff9f14a03225df55997cb2ca74ff60ecaf317b9e033ea93386785db84161

Tags:FILE

CAPE_Icedidhook
MalwareCAPE Sandbox (CAPEv2)· kevoreilly· 2021-03-30
CAPE_Icedidpackera
MalwareCAPE Sandbox (CAPEv2)· kevoreilly· 2021-03-30
CAPE_Icedidpackerb
MalwareCAPE Sandbox (CAPEv2)· kevoreilly· 2021-03-30
CAPE_Icedidpackerc
MalwareCAPE Sandbox (CAPEv2)· kevoreilly· 2021-03-30
CAPE_Icedidpackerd
MalwareCAPE Sandbox (CAPEv2)· kevoreilly· 2021-03-30
CAPE_Icedsleep
MalwareCAPE Sandbox (CAPEv2)· kevoreilly· 2021-03-30
SIGNATURE_BASE_MAL_Icedid_GZIP_LDR_202104
MalwareSignature Base (Florian Roth / Nextron)· Thomas Barabosch, Telekom Security· 2021-04-12
MALPEDIA_Win_Icedid_Auto
MalwareMalpedia signator rules· Felix Bilstein - yara-signator at cocacoding dot com· 2026-05-04

More Icedid rules