Malicious PDF — malware analysis report

Static analysis result for SHA-256 1cf4b027a3f1c33d…

MALICIOUS

PDF

29.3 KB
MD5: 51a1d5f7b2ac6c631581ff6040ed984e SHA-1: 8a68c04b2e193439a44cfb309aaef65160669c4f SHA-256: 1cf4b027a3f1c33d903d2c1baefe5eec96809805a3f113fad3091de6d9edbe10
274 Risk Score

Malware Insights

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

The PDF file contains embedded JavaScript that utilizes `eval()` and `unescape()` functions, indicating obfuscated code execution. This script is responsible for loading an embedded SWF (Flash) file. The presence of ClamAV detections for 'Pdf.Exploit.Agent' and 'Pdf.Exploit.Agent' on an extracted artifact further confirms malicious intent. The overall attack pattern suggests a multi-stage exploit leveraging PDF vulnerabilities to deliver a secondary payload via Flash.

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 0xC30 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 0x834 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
968a643379fbb1b053f5e78ee6218e14b75c1eb0f619cc907fdb632a951459d4
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0x64 3482 bytes