Malicious PDF — malware analysis report

Static analysis result for SHA-256 915ffd515cc3cb2c…

MALICIOUS

PDF

29.2 KB
MD5: c97cbb8d4e53ae80b20cf1d6ea77f912 SHA-1: e37dbe1f18aa13c8dcf3d65d97322199b04985b6 SHA-256: 915ffd515cc3cb2cb73646a79bdefd32665aefc9ddfac57edbb757a451562f93
304 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 Command and Scripting Interpreter: PowerShell T1204.002 Malicious File: Malicious Applet

The PDF contains embedded JavaScript that utilizes eval() and unescape() functions, indicating obfuscated code execution. This JavaScript is likely responsible for loading the embedded SWF (Flash) file, which is a known vector for exploits. The ML classifier and ClamAV detections strongly support the malicious nature of this PDF, classifying it as an exploit attempting to deliver a secondary payload.

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 0xC22 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 0x826 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
07127cb489ea0c6f7a9e14143e37cad8b399b7dca67ad9d3938debaa9ee83bf6
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0x64 3458 bytes