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SHA-3 (Keccak) interleaved round constants

yara LOW Yara-Rules
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This rule was pulled from an open-source repository and enriched with AI. Validate in a test environment before deploying to production.
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Retrieved: 2026-05-06T11:00:00Z · Confidence: medium

Hunt Hypothesis

The detection of SHA-3 (Keccak) interleaved round constants may indicate the use of custom cryptographic implementations or obfuscation techniques by adversaries. SOC teams should proactively hunt for this behavior in Azure Sentinel to identify potential advanced persistent threats or data exfiltration attempts leveraging cryptographic anomalies.

YARA Rule

rule SHA3_interleaved {
	meta:
		author = "spelissier"
		description = "SHA-3 (Keccak) interleaved round constants"
		date = "2020-04"
		version = "0.1"
	strings:
		$c0  = { 010000008b800000 }
		$c1  = { 0000000081000080 }
		$c2  = { 0000000088000080 }
		$c3  = { 000000000b000000 }
		$c4  = { 0100000000800000 }
		$c5  = { 010000008b000000 }
		$c6  = { 0100000082800000 }
		$c7  = { 0000000003800000 }
		$c8  = { 010000008a000080 }
		$c9  = { 0000000082800080 }
		$c10 = { 0000000003800080 }
		$c11 = { 000000008b000080 }
		$c12 = { 0000000083000000 }
		$c13 = { 000000000a000000 }
		$c14 = { 0000000080800080 }
		$c15 = { 0100000082000080 }
		$c16 = { 010000000b000080 }
		$c17 = { 0100000088800080 }
		$c18 = { 0000000008000080 }
		$c19 = { 0100000000000000 }
		$c20 = { 0000000089000000 }
		$c21 = { 0100000081000080 }
	condition:
		10 of them
}

Deployment Notes

This YARA rule can be deployed in the following contexts:

This rule contains 22 string patterns in its detection logic.

False Positive Guidance

Original source: https://github.com/Yara-Rules/rules/blob/main/crypto/crypto_signatures.yar