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YARA · Signature Base (Florian Roth / Nextron)

SIGNATURE_BASE_SUSP_LNX_Sindoor_ELF_Obfuscation_Aug25

Detects ELF obfuscation technique used by Sindoor dropper related to APT 36

Suspicious / huntingSignature Base (Florian Roth / Nextron)Detection Rule License 1.1Compiles with YARA-X
Author
Pezier Pierre-Henri
Date
2025-08-29
Modified
2026-05-15
Score / Quality
70 / 85

What this rule detects

Detects ELF obfuscation technique used by Sindoor dropper related to APT 36

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

Summary generated from the rule's metadata and condition.

Rule source

Download .yar
susp-lnx-sindoor-elf-obfuscation-aug25.yarDetection Rule License 1.1
rule SIGNATURE_BASE_SUSP_LNX_Sindoor_ELF_Obfuscation_Aug25 : FILE
{
	meta:
		description = "Detects ELF obfuscation technique used by Sindoor dropper related to APT 36"
		author = "Pezier Pierre-Henri"
		id = "97802224-0d8b-5691-a6f1-f031626cda53"
		date = "2025-08-29"
		modified = "2026-05-15"
		reference = "Internal Research"
		source_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/yara/apt_apt36_operation_sindoor.yar#L1-L17"
		license_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
		hash = "6879a2b730e391964afe4dbbc29667844ba0c29239be5503b7c86e59e7052443"
		logic_hash = "c1258c1f6d4b49104bedf3fbef932f1775ede7d32191df2e5479ca9b291add9e"
		score = 70
		quality = 85
		tags = "FILE"

	strings:
		$s1 = "UPX!"

	condition:
		filesize < 10MB and uint16( 0 ) == 0 and uint16( 4 ) > 0 and $s1 in ( 0xc0 .. 0x100 )
}

Strings (1 patterns)

IdentifierTypeValueModifiers
$s1text"UPX!"

Condition

filesize < 10MB and uint16( 0 ) == 0 and uint16( 4 ) > 0 and $s1 in ( 0xc0 .. 0x100 )

In plain words (Heuristic)

  • The file must be smaller than 10MB (a cheap guard that skips large files).
  • Pattern $s1 must be found within the range 0xc0 .. 0x100.

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.

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Sample hashes

Hashes of samples the author lists in the rule's meta (look them up in your threat-intelligence platform).

  • 6879a2b730e391964afe4dbbc29667844ba0c29239be5503b7c86e59e7052443

Licence & attribution

Author: Pezier Pierre-Henri

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: 97802224-0d8b-5691-a6f1-f031626cda53

Tags:FILE

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