YARA Rule: rook.yar

Sponsored by Hudson Rock – Use Hudson Rock's free cybercrime intelligence tools to learn how Infostealer infections are leading to ransomware attacks

Valid Rule

/*
Rook ransomware (Babuk-based)
*/

rule Rook_Ransomnote
{
    meta:
        author = "ransomware.live"
        family = "ransomware.rook"
        description = "Detects Rook ransomware ransom note"
        date = "2026-05-04"
        severity = 7
        score = 70

    strings:
        $s1 = "HowToRestoreYourFiles.txt" ascii nocase
        $s2 = "ROOK" ascii
        $s3 = "rook" ascii
        $s4 = ".rook" ascii

    condition:
        2 of them
}