Malicious PDF — malware analysis report

Static analysis result for SHA-256 efcfc10492a3358f…

MALICIOUS

PDF

34.8 KB Created: ;œDß³F/¦YMBI„ª¶ žÜD;› Authoring application: Yv¬‚Ӗ |x؛ý (via Yv¿‚ٖ|xԛê‹Ü)
MD5: ed2084f543b4348d0511d9009f663c29 SHA-1: 682afa88e3d775b53b980b361838ac6e3292b1d9 SHA-256: efcfc10492a3358f523dbc0944fd53ddced156f54d523084e584f3900b4fa418
94 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1566.001 Spearphishing Attachment T1027 Obfuscated Files or Information

This PDF was flagged as malicious by an ML classifier and contains embedded JavaScript. The JavaScript stream is likely used to obfuscate and deliver a malicious payload, as indicated by the 'PDF_ENCRYPTED_WITH_JS' heuristic. The presence of JavaScript actions and streams within an encrypted PDF strongly suggests an attempt to bypass static analysis and execute harmful code.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

Heuristics 4

  • Encrypted PDF carries /JavaScript — payload hidden from static analysis high PDF_ENCRYPTED_WITH_JS
    PDF declares /Encrypt and also references an executable trigger (/JavaScript). Document encryption hides the JavaScript body and stream contents from static scanners — combined with auto-execution indicators this is a known evasion pattern used to deliver weaponised JavaScript that the analyst cannot inspect without the decryption key.
  • JavaScript action low PDF_JAVASCRIPT
    PDF contains a /JavaScript action. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • Optional Content Group with action trigger low PDF_OPTIONAL_CONTENT
    Optional Content Group (layer) co-occurs with an action trigger — content can be selectively hidden from viewers or scanners while the action still fires on open

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0009_000.js
1c21b037ca00ef80150c55b989e30a32c0540c7b350c5414d6e850cb16b31c0e
pdf-javascript-stream PDF /JS object 9 at offset 0x3D7 32974 bytes