Skip to content

YARA · SEKOIA.IO Community

SEKOIA_Ta410_Control_Flow_Obfuscation

Detects control flow obfuscation used by TA410 in XXXModule_dlcore0

Suspicious / huntingSEKOIA.IO CommunityDetection Rule License 1.1Compiles with YARA-X
Author
Sekoia.io
Date
2022-10-11
Modified
2024-12-19
Score / Quality
75 / 80

What this rule detects

Detects control flow obfuscation used by TA410 in XXXModule_dlcore0

Targets: Windows PE.

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

Summary generated from the rule's metadata and condition.

Rule source

ta410-control-flow-obfuscation.yarDetection Rule License 1.1
rule SEKOIA_Ta410_Control_Flow_Obfuscation : FILE
{
	meta:
		description = "Detects control flow obfuscation used by TA410 in XXXModule_dlcore0"
		author = "Sekoia.io"
		id = "2a784f9b-3624-4c5d-8a64-db7d3c33a8f7"
		date = "2022-10-11"
		modified = "2024-12-19"
		reference = "https://github.com/SEKOIA-IO/Community"
		source_url = "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/yara_rules/ta410_control_flow_obfuscation.yar#L1-L24"
		license_url = "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/LICENSE.md"
		hash = "6cf78943728286d0bddd99049d81065673ab7f679029cdd5f5dc69f90197136e"
		logic_hash = "3ee6ee07e7a7be285290ec91de649afff3e5dc222bcfc58709b642d4dd53dc41"
		score = 75
		quality = 80
		tags = "FILE"
		version = "1.0"
		classification = "TLP:CLEAR"

	strings:
		$chunk_1 = {
        E8 ?? ?? ?? ??
        83 C0 10
        3D 00 00 00 80
        7D 01
        EB ff
        }
		$chunk_2 = {83 C0 10 3D 00 00 00 80 7d 01 eb ff e0 50 c3 75}

	condition:
		uint16be( 0 ) == 0x4d5a and filesize < 10MB and any of them
}

Strings (2 patterns)

IdentifierTypeValueModifiers
$chunk_1hex{ E8 ?? ?? ?? ?? 83 C0 10 3D 00 00 00 80 7D 01 EB ff }
$chunk_2hex{83 C0 10 3D 00 00 00 80 7d 01 eb ff e0 50 c3 75}

Condition

uint16be( 0 ) == 0x4d5a and filesize < 10MB and any of them

In plain words (Heuristic)

  • The file must start with “MZ” — a Windows executable (PE).
  • The file must be smaller than 10MB (a cheap guard that skips large files).
  • At least one pattern 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).

  • 6cf78943728286d0bddd99049d81065673ab7f679029cdd5f5dc69f90197136e

Licence & attribution

Author: Sekoia.io

Source repository: SEKOIA.IO Community @ a438a5901a

Licence: Detection Rule License 1.1 (repository licence)

Original rule

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

Rule id: 2a784f9b-3624-4c5d-8a64-db7d3c33a8f7

Metadata

version1.0
classificationTLP:CLEAR

Tags:FILE