Malicious PDF — malware analysis report

Static analysis result for SHA-256 228712cb8a08509e…

MALICIOUS

PDF

29.3 KB
MD5: 0004425d4baa56b00c25b1e7b94fb838 SHA-1: 84d1f84a351218b4b269f469ae9a378d04d1e3ec SHA-256: 228712cb8a08509ed7b413a8fa17a4d4efcd6a84bdc6a6e8f7d2efacdea45669
304 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 JavaScript T1559.002 Component Object Model T1204.002 Malicious File

This PDF file contains embedded JavaScript that utilizes eval() and unescape() functions, indicating an attempt to obfuscate malicious code. The JavaScript is likely responsible for loading and executing the embedded SWF (Flash) file, which is a common technique for delivering secondary payloads. ClamAV detections further confirm the malicious nature of the PDF and its extracted components.

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 0xC2B 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 0x82F 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
374859f238ca4625084d58c3fe95bc45d62d10a1595154536906d41b730b5006
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0x64 3476 bytes