Malicious PDF — malware analysis report

Static analysis result for SHA-256 f5a7a5cf0a4e5b5c…

MALICIOUS

PDF

14.5 KB
MD5: 2264cb58e0d416cc9985fc8f72be1e2a SHA-1: 3fb6a711c6633c44b6ac1340f11b4ebbe2d8199e SHA-256: f5a7a5cf0a4e5b5c34c00cbc75cee50a30b0f8fe952ceed5ab91a8b3b730222f
158 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 Malicious File: User Execution: Malicious File

The PDF contains embedded JavaScript which utilizes `eval()` and `String.fromCharCode` for obfuscation. This JavaScript is likely responsible for executing an exploit, as indicated by the ML classifier and ClamAV detection (Pdf.Exploit.Dropped-94). The primary IOC is the file's SHA256 hash.

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 0x3898 144 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s).