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YARA · Signature Base (Florian Roth / Nextron)

SIGNATURE_BASE_SUSP_JAVA_Loader_Indicators_Aug25

Detects indicators of a Java loader used in phishing campaigns

Suspicious / huntingSignature Base (Florian Roth / Nextron)Detection Rule License 1.1Compiles with YARA-X
Author
Florian Roth
Date
2025-08-07
Modified
2026-05-15
Score / Quality
70 / 85

What this rule detects

Detects indicators of a Java loader used in phishing campaigns

It defines 3 patterns (3 text, 0 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

Download .yar
susp-java-loader-indicators-aug25.yarDetection Rule License 1.1
rule SIGNATURE_BASE_SUSP_JAVA_Loader_Indicators_Aug25 : FILE
{
	meta:
		description = "Detects indicators of a Java loader used in phishing campaigns"
		author = "Florian Roth"
		id = "ed83b697-4e48-504c-8a65-af0a5b765c9d"
		date = "2025-08-07"
		modified = "2026-05-15"
		reference = "https://www.malwation.com/blog/technical-analysis-of-a-stealth-java-loader-used-in-phishing-campaigns-targeting-turkiye"
		source_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/yara/mal_soupdealer_java_aug25.yar#L26-L45"
		license_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
		hash = "c4cf746fce283878dde567e5457a8ebdbb7ff3414be46569ecdd57338bd96fa1"
		logic_hash = "ac610cd6d3030f49058d5e6f059b746cf3da05ca3cdc8f2be2f5f1cfec2ff665"
		score = 70
		quality = 85
		tags = "FILE"

	strings:
		$s1 = "Loader.classPK" ascii fullword
		$s2 = "stubPK" ascii
		$s3 = "META-INF/MANIFEST.MFPK" ascii

	condition:
		uint16( 0 ) == 0x4b50 and filesize < 500KB and $s1 in ( filesize - 224 .. filesize ) and $s2 in ( filesize - 224 .. filesize ) and $s3 in ( filesize - 224 .. filesize )
}

Strings (3 patterns)

IdentifierTypeValueModifiers
$s1text"Loader.classPK"ascii fullword
$s2text"stubPK"ascii
$s3text"META-INF/MANIFEST.MFPK"ascii

Condition

uint16( 0 ) == 0x4b50 and filesize < 500KB and $s1 in ( filesize - 224 .. filesize ) and $s2 in ( filesize - 224 .. filesize ) and $s3 in ( filesize - 224 .. filesize )

In plain words (Heuristic)

  • The file must start with “PK” — a ZIP archive (also Office Open XML, JAR, APK).
  • The file must be smaller than 500KB (a cheap guard that skips large files).
  • Pattern $s1 must be found within the range filesize - 224 .. filesize.
  • Pattern $s2 must be found within the range filesize - 224 .. filesize.
  • Pattern $s3 must be found within the range filesize - 224 .. filesize.

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References

Sample hashes

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

  • c4cf746fce283878dde567e5457a8ebdbb7ff3414be46569ecdd57338bd96fa1

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: ed83b697-4e48-504c-8a65-af0a5b765c9d

Tags:FILE

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