Malicious PDF — malware analysis report

Static analysis result for SHA-256 44cbcc4305b3385c…

MALICIOUS

PDF

29.2 KB
MD5: fbac8ef7491f819f83a6fafffe2233ee SHA-1: 90f536a280608cdc14295c258bb0cfe3ba794cf7 SHA-256: 44cbcc4305b3385c7e76990caea30dd66120bd2d71965c29db2a63c47e417203
304 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1204.002 Malicious File

The PDF contains embedded JavaScript and a Flash object (SWFNAME.swf), both of which are commonly used to exploit vulnerabilities in viewers. Heuristics indicate the presence of JavaScript actions, eval(), unescape(), and String.fromCharCode(), suggesting obfuscated code designed to execute malicious actions. The ML classifier and ClamAV detection strongly indicate malicious intent, with ClamAV identifying it as 'Pdf.Exploit.Agent'. The extracted artifacts, including SWFNAME.swf and javascript files, are likely components of the exploit chain.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 10

  • ClamAV: Pdf.Exploit.Agent-36098 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Exploit.Agent-36098
  • ClamAV detection on extracted artifact critical EXTRACTED_FILE_CLAMAV
    ClamAV flagged at least one file extracted from inside this sample. Even when the wrapping document carries no AV detection of its own, a hit on the carved artifact is a strong indicator the sample is a delivery vehicle.
  • RichMedia (Flash) high PDF_RICHMEDIA
    PDF contains /RichMedia (Adobe Flash) which is a historic exploit vector
  • eval() call high PDF_EVAL
    eval() found — commonly used for obfuscated exploit execution (matched inside decoded stream)
  • unescape() call high PDF_UNESCAPE
    unescape() found — often used to decode shellcode in PDF JS exploits (matched inside decoded stream)
  • 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.
  • Embedded file low PDF_EMBEDDED
    PDF embeds a file attachment — could carry an executable or another weaponised document as a nested payload
  • String.fromCharCode low PDF_FROMCHARCODE
    String.fromCharCode found — used to construct payload strings dynamically. Common in benign JavaScript libraries for codepoint manipulation, so this alone is informational; weaponised use is also caught by the dedicated fromCharCode-stage and exploit-shape rules. (matched inside decoded stream)
  • Suspicious extracted artifact info EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
SWFNAME.swf
a98024b4ee1377e872e3ebaf1c361600c270db5fd5ba79f256106c0c566dde29
pdf-embedded-file PDF EmbeddedFile object 16 at offset 0xC23 26777 bytes
Detection
ClamAV: Pdf.Exploit.Agent-35955
Obfuscation or payload: likely
Carved artifact entropy is 7.99, consistent with packed or encrypted content.
javascript_obj0006_000.js
e1ab3bbf30605cecdce6db9d2556198626dbb178f7a4cb471a9436bb6e8bd92f
pdf-javascript-stream PDF /JS object 6 at offset 0x827 462 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 3 eval/decoder/string-building token(s).
legacy_pdfkit_stage_000.js
ee71c5dcd5964e403dceecc9517b734e265f94eec1c8f327bf39b666eaf3293d
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0x64 3458 bytes