PDF_with_Embedded_RTF_OLE_Newlines

YARA detection rule by InQuest Labs · GPL-2.0

This signature detects suspicious PDF files embedded with RTF files that contain embedded OLE content that injects newlines into embedded OLE contents as a means of payload obfuscation and detection evasion.

rule PDF_with_Embedded_RTF_OLE_Newlines
{
    meta:
        author         = "InQuest Labs"
        description    = "This signature detects suspicious PDF files embedded with RTF files that contain embedded OLE content that injects newlines into embedded OLE contents as a means of payload obfuscation and detection evasion."
        created_date   = "2022-03-15"
        updated_date   = "2022-03-15"
        blog_reference = "InQuest Internal Research"
        labs_reference = "N/A"
        labs_pivot     = "N/A"
        samples        = "d784c53b8387f1e2f1bcb56a3604a37b431638642e692540ebeaeee48c1f1a07"

 	strings:
			$rtf_magic = "{\\rt"                  
$rtf_objdata = /\x7b[^\x7d]*\\objdata/ nocase
        
$nor = "D0CF11E0A1B11AE1" nocase
        
$obs = /D[ \r\t\n]*0[ \r\t\n]*C[ \r\t\n]*F[ \r\t\n]*1[ \r\t\n]*1[ \r\t\n]*E[ \r\t\n]*0[ \r\t\n]*A[ \r\t\n]*1[ \r\t\n]*B[ \r\t\n]*1[ \r\t\n]*1[ \r\t\n]*A[ \r\t\n]*E[ \r\t\n]*1/ nocase
	condition:
			$rtf_magic and $rtf_objdata and ($obs and not $nor)
}

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

163f4516-f1f2-4805-a5a1-17daaa28c11d

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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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