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SEKOIA_Apt_Lazarus_Lambload_Timecheck

Detects timeCheck routine in LambLoad

APT / threat actorLambloadSEKOIA.IO CommunityDetection Rule License 1.1Compiles with YARA-X
Author
Sekoia.io
Date
2023-11-27
Modified
2024-12-19
Score / Quality
75 / 80

What this rule detects

Detects timeCheck routine in LambLoad

Associated malware family: Lambload.

Targets: Windows PE.

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

Summary generated from the rule's metadata and condition.

Rule source

apt-lazarus-lambload-timecheck.yarDetection Rule License 1.1
rule SEKOIA_Apt_Lazarus_Lambload_Timecheck : FILE
{
	meta:
		description = "Detects timeCheck routine in LambLoad"
		author = "Sekoia.io"
		id = "8807c752-c34e-4c3b-9194-3a9bd2575a88"
		date = "2023-11-27"
		modified = "2024-12-19"
		reference = "https://www.microsoft.com/en-us/security/blog/2023/11/22/diamond-sleet-supply-chain-compromise-distributes-a-modified-cyberlink-installer/"
		source_url = "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/yara_rules/apt_lazarus_lambload_timecheck.yar#L1-L67"
		license_url = "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/LICENSE.md"
		logic_hash = "019e559f3596cf83f7e7ada05f6550b50b2d45d577600fa549470b98af93e23b"
		score = 75
		quality = 80
		tags = "FILE"
		version = "1.0"
		classification = "TLP:CLEAR"

	strings:
		$chunk_1 = {
        0F 85 ?? ?? ?? ??
        8D 85 ?? ?? ?? ??
        50
        E8 ?? ?? ?? ??
        83 C4 ??
        83 78 ?? ??
        0F 85 ?? ?? ?? ??
        8B 48 ??
        83 F9 ??
        0F 8C ?? ?? ?? ??
        83 F9 ??
        0F 8D ?? ?? ?? ??
        8B 40 ??
        83 F8 ??
        0F 8C ?? ?? ?? ??
        83 F8 ??
        0F 8D ?? ?? ?? ??
        53
        57
        68 ?? ?? ?? ??
        8D 85 ?? ?? ?? ??
        6A ??
        50
        C7 85 ?? ?? ?? ?? ?? ?? ?? ??
        }

	condition:
		uint16be( 0 ) == 0x4d5a and any of them
}

Strings (1 patterns)

IdentifierTypeValueModifiers
$chunk_1hex{ 0F 85 ?? ?? ?? ?? 8D 85 ?? ?? ?? ?? 50 E8 ?? ?? ?? ?? 83 C4 ?? 83 78 ?? ?? 0F 85 ?? ?? ?? ?? 8 …

Condition

uint16be( 0 ) == 0x4d5a 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: 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: 8807c752-c34e-4c3b-9194-3a9bd2575a88

Metadata

version1.0
classificationTLP:CLEAR

Tags:FILE