Detectionmediumtest

Payload Decoded and Decrypted via Built-in Utilities

Detects when a built-in utility is used to decode and decrypt a payload after a macOS disk image (DMG) is executed. Malware authors may attempt to evade detection and trick users into executing malicious code by encoding and encrypting their payload and placing it in a disk image file. This behavior is consistent with adware or malware families such as Bundlore and Shlayer.

Convert In Phoenix Studio

Open this Sigma rule in the converter with the YAML preloaded and ready for backend selection.

Launch

Tim Rauch, Elastic SecurityCreated Mon Oct 17234dc5df-40b5-49d1-bf53-0d44ce778ecamacos

Log Source

macOSProcess Creation

ProductmacOS← raw: macos

CategoryProcess Creation← raw: process_creation

Events generated when a new process is spawned on the system. Covers command-line arguments, parent/child relationships, and process metadata.

Detection Logic

detection:
    selection:
        Image|endswith: '/openssl'
        CommandLine|contains|all:
            - '/Volumes/'
            - 'enc'
            - '-base64'
            - ' -d '
    condition: selection