Skip to content
yararules.org
Menu

YARA · Signature Base (Florian Roth / Nextron)

SIGNATURE_BASE_SUSP_Script_Base64_Blocks_Jun20_1

Detects suspicious file with base64 encoded payload in blocks

Suspicious / huntingSignature Base (Florian Roth / Nextron)Detection Rule License 1.1Compiles with YARA-X (with warnings)
Author
Florian Roth (Nextron Systems)
Date
2020-06-05
Modified
2026-05-15
Score / Quality
70 / 85

What this rule detects

Detects suspicious file with base64 encoded payload in blocks

It defines 2 patterns (1 text, 1 hex, 0 regex).

YARA-X says: warning[text_as_hex]: hex pattern could be written as text literal

Summary generated from the rule's metadata and condition.

Rule source

Download .yar
susp-script-base64-blocks-jun20-1.yarDetection Rule License 1.1
rule SIGNATURE_BASE_SUSP_Script_Base64_Blocks_Jun20_1
{
	meta:
		description = "Detects suspicious file with base64 encoded payload in blocks"
		author = "Florian Roth (Nextron Systems)"
		id = "cef759a5-b02a-53e7-bf27-184eee6bc3fa"
		date = "2020-06-05"
		modified = "2026-05-15"
		reference = "https://posts.specterops.io/covenant-v0-5-eee0507b85ba"
		source_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/yara/gen_susp_obfuscation.yar#L86-L99"
		license_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
		logic_hash = "7d456cbbbd76f543afe144a2876a02db834aa6b09ecd4d6aa2f25ce8eeac5de8"
		score = 70
		quality = 85
		tags = ""

	strings:
		$sa1 = "<script language=" ascii
		$sb2 = { 41 41 41 22 2B 0D 0A 22 41 41 41 }

	condition:
		all of them
}

Strings (2 patterns)

IdentifierTypeValueModifiers
$sa1text"<script language="ascii
$sb2hex{ 41 41 41 22 2B 0D 0A 22 41 41 41 }

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 (Nextron Systems)

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: cef759a5-b02a-53e7-bf27-184eee6bc3fa

Related rules