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SEKOIA_Apt_Oilrig_Webshell

Detects a webshell used by OilRig

APT / threat actorSEKOIA.IO CommunityDetection Rule License 1.1Compiles with YARA-X
Author
Sekoia.io
Date
2024-10-23
Modified
2024-12-19
Score / Quality
75 / 80

What this rule detects

Detects a webshell used by OilRig

It defines 4 patterns (4 text, 0 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

apt-oilrig-webshell.yarDetection Rule License 1.1
rule SEKOIA_Apt_Oilrig_Webshell : FILE
{
	meta:
		description = "Detects a webshell used by OilRig"
		author = "Sekoia.io"
		id = "53955117-5176-4682-89ad-1503faba42aa"
		date = "2024-10-23"
		modified = "2024-12-19"
		reference = "https://github.com/SEKOIA-IO/Community"
		source_url = "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/yara_rules/apt_oilrig_webshell.yar#L1-L18"
		license_url = "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/LICENSE.md"
		logic_hash = "0e0879bafa1becf7e4aef008229a79ab8e0c50eda03232abd5cbb8fc59f482d3"
		score = 75
		quality = 80
		tags = "FILE"
		version = "1.0"
		classification = "TLP:CLEAR"

	strings:
		$ = "string d = com;"
		$ = "string p = fu;"
		$ = "#@rt12!@$$$nnMF##"
		$ = "messi(d)))"

	condition:
		2 of them and filesize < 80KB
}

Strings (4 patterns)

IdentifierTypeValueModifiers
$text"string d = com;"
$text"string p = fu;"
$text"#@rt12!@$$$nnMF##"
$text"messi(d)))"

Condition

2 of them and filesize < 80KB

In plain words (Heuristic)

  • The file must be smaller than 80KB (a cheap guard that skips large files).
  • At least 2 patterns in the rule must match.

Test this rule in your browser

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Drop a file here or click to chooseScanned locally with YARA-X. Files up to 200 MB.

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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: 53955117-5176-4682-89ad-1503faba42aa

Metadata

version1.0
classificationTLP:CLEAR

Tags:FILE