Skip to content
yararules.org
Menu

YARA · Signature Base (Florian Roth / Nextron)

SIGNATURE_BASE_MAL_JS_Efile_Apr23_1

Detects JavaScript malware used in eFile compromise

MalwareSignature Base (Florian Roth / Nextron)Detection Rule License 1.1Compiles with YARA-X
Author
Florian Roth
Date
2023-04-06
Modified
2023-12-05
Score / Quality
75 / 85

What this rule detects

Detects JavaScript malware used in eFile compromise

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

Summary generated from the rule's metadata and condition.

Rule source

Download .yar
mal-js-efile-apr23-1.yarDetection Rule License 1.1
rule SIGNATURE_BASE_MAL_JS_Efile_Apr23_1
{
	meta:
		description = "Detects JavaScript malware used in eFile compromise"
		author = "Florian Roth"
		id = "ba7a8b2c-789c-5bc5-be53-f2b92c7039e1"
		date = "2023-04-06"
		modified = "2023-12-05"
		reference = "https://twitter.com/Ax_Sharma/status/1643178696084271104/photo/1"
		source_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/yara/mal_efile_apr23.yar#L2-L15"
		license_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
		logic_hash = "6d94162e5719b92d9df349e7d48cd70e218998b0e120870a435a8073fa49c532"
		score = 75
		quality = 85
		tags = ""

	strings:
		$s1 = "let payload_chrome = "
		$s2 = "else if (agent.indexOf(\"firefox"

	condition:
		all of them
}

Strings (2 patterns)

IdentifierTypeValueModifiers
$s1text"let payload_chrome = "
$s2text"else if (agent.indexOf(\"firefox"

Condition

all of them

In plain words (Heuristic)

  • 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

Licence & attribution

Author: Florian Roth

Source repository: Signature Base (Florian Roth / Nextron) @ 94a1c48d7a

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: ba7a8b2c-789c-5bc5-be53-f2b92c7039e1

Related rules