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SEKOIA_Apt_Rusticweb_Stealer

Detects stealer used by RusticWeb

APT / threat actorSEKOIA.IO CommunityDetection Rule License 1.1Compiles with YARA-X
Author
Sekoia.io
Date
2024-01-09
Modified
2024-12-19
Score / Quality
75 / 80

What this rule detects

Detects stealer used by RusticWeb

Targets: Windows PE.

It defines 5 patterns (5 text, 0 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

apt-rusticweb-stealer.yarDetection Rule License 1.1
rule SEKOIA_Apt_Rusticweb_Stealer : FILE
{
	meta:
		description = "Detects stealer used by RusticWeb"
		author = "Sekoia.io"
		id = "813072e0-28de-4cb7-b2cc-71d77a1e8508"
		date = "2024-01-09"
		modified = "2024-12-19"
		reference = "https://github.com/SEKOIA-IO/Community"
		source_url = "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/yara_rules/apt_rusticweb_stealer.yar#L1-L19"
		license_url = "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/LICENSE.md"
		logic_hash = "68f802ef442e68cbcca789eae2bb8a4395af86699320e5a8101c07469e7555fb"
		score = 75
		quality = 80
		tags = "FILE"
		version = "1.0"
		classification = "TLP:CLEAR"

	strings:
		$s1 = "-FTT=@"
		$s2 = "https://oshi.at"
		$s3 = "curl-T"
		$s4 = "upload/upload.php"
		$s5 = "cargo"

	condition:
		uint16be( 0 ) == 0x4d5a and filesize < 4MB and 3 of them
}

Strings (5 patterns)

IdentifierTypeValueModifiers
$s1text"-FTT=@"
$s2text"https://oshi.at"
$s3text"curl-T"
$s4text"upload/upload.php"
$s5text"cargo"

Condition

uint16be( 0 ) == 0x4d5a and filesize < 4MB and 3 of them

In plain words (Heuristic)

  • The file must start with “MZ” — a Windows executable (PE).
  • The file must be smaller than 4MB (a cheap guard that skips large files).
  • At least 3 patterns 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: 813072e0-28de-4cb7-b2cc-71d77a1e8508

Metadata

version1.0
classificationTLP:CLEAR

Tags:FILE