Malicious PDF — malware analysis report

Static analysis result for SHA-256 9c715b7368557613…

MALICIOUS

PDF

4.6 KB Created: 2009-05-06 20:45:24 +08:00
MD5: 0fc9c4e1e2148912188dd913ff95149e SHA-1: 06de1964ed1bc0205856f7fff1bd0af91d7d63f6 SHA-256: 9c715b7368557613911e6e813d8a4e93c43e307b086bbfa0be4905a7910155d4
216 Risk Score

Malware Insights

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

The PDF contains embedded JavaScript, indicated by PDF_JAVASCRIPT and PDF_JS heuristics. The ML classifier and ClamAV detection (Pdf.Dropper.Agent-1846392) strongly suggest malicious intent. The JavaScript stream, decoded using unescape() and String.fromCharCode, likely functions as a dropper, as evidenced by the extracted artifact 'javascript_obj0001_000.js' and ClamAV's detection of an extracted exploit artifact (Pdf.Exploit.Agent-35646). The primary function appears to be downloading and executing a second-stage payload.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 7

  • ClamAV: Pdf.Dropper.Agent-1846392 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Dropper.Agent-1846392
  • 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.
  • 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.
  • 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 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0001_000.js
3ffb265e9bad97c6f70e70c1056568559c9825ff6c755fa86ac369ee6837c32a
pdf-javascript-stream PDF /JS object 1 at offset 0xF 5723 bytes
Detection
ClamAV: Pdf.Exploit.Agent-35646
Obfuscation or payload: likely
Carved artifact contains 7 eval/decoder/string-building token(s).