pe_overlay_single_byte_xor_PE

YARA detection rule by filescanio

Try the 3rd byte as a XOR key, since typically that byte is zero in a PE, meaning in encoded form it will contain the XOR key

import "pe"
rule pe_overlay_single_byte_xor_PE : hardened
{
	meta:
		description = "Try the 3rd byte as a XOR key, since typically that byte is zero in a PE, meaning in encoded form it will contain the XOR key"
		score = 75

	condition:
		pe.is_pe and pe.overlay.offset != 0x0 and uint16( pe.overlay.offset ) != 0x5a4d and int8 ( pe.overlay.offset ) ^ uint8( pe.overlay.offset + 3 ) == 0x4d and uint8( pe.overlay.offset + 1 ) ^ uint8( pe.overlay.offset + 3 ) == 0x5a
}

[[ currentRule.title && currentRule.title.length > 60 ? currentRule.title.slice(0, 60) + '…' : currentRule.title ]]

21fa0a3a-d2a0-47dc-b576-2b0cb0e90bda

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Executable code, not a declarative rule

This submission is arbitrary [[ currentRule.format ? currentRule.format.toUpperCase() : '' ]] code, not a declarative detection rule — review it as you would any script before running it, and note that it cannot be safely aggregated or auto-executed alongside YARA/Sigma/Suricata/CRS rules.

Rejected pattern present

[[ reason ]]

What does this mean?

Format & documentation suggestions

Not a security issue — this rule is valid and was accepted as-is. These are optional fields/conventions its own format recommends, mainly affecting its quality score and how well it documents itself for other reviewers.

[[ reason ]]

What do these messages mean?

[[ currentRule.title && currentRule.title.length > 60 ? currentRule.title.slice(0, 60) + '…' : currentRule.title ]]

[[ currentRule.title ]]

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