Malicious PDF — malware analysis report

Static analysis result for SHA-256 3f8b9fc9c9e129ba…

MALICIOUS

PDF

14.6 KB
MD5: 1f99025ffdce9ea99546a5fd433dfed0 SHA-1: 441e1651d772d95ee554221058444b2744be6d53 SHA-256: 3f8b9fc9c9e129ba32ca843db9f40cb09e58797449a5c103c50d3b5888c393bc
156 Risk Score

Malware Insights

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

This PDF file was flagged as malicious by ClamAV (Pdf.Exploit.Dropped-94) and a machine learning classifier. Static analysis revealed embedded JavaScript containing an eval() call and String.fromCharCode, indicating obfuscation. The JavaScript is likely used to download and execute a second-stage payload, a common technique for PDF-based exploits. No specific family could be identified.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 6

  • ClamAV: Pdf.Exploit.Dropped-94 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Exploit.Dropped-94
  • eval() call high PDF_EVAL
    eval() found — commonly used for obfuscated exploit execution (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.
  • 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_obj0076_000.js
c28effae366bd4b2a63fe29aea090a07947ae4e73aa9efc1cf87e16e006e7288
pdf-javascript-stream PDF /JS object 76 at offset 0x3924 144 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s).