Malicious PDF — malware analysis report

Static analysis result for SHA-256 a7c3fcc9e1b52bde…

MALICIOUS

PDF

15.8 KB
MD5: 40467b6f21c7caf263429ea159285b2a SHA-1: f4244b052d5121bcb4843852795d768b16519930 SHA-256: a7c3fcc9e1b52bdec479416d173aafa26d8a6f564017ca6645281c7faf325d4f
166 Risk Score

Malware Insights

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

The PDF file contains embedded JavaScript that utilizes eval() and String.fromCharCode, indicating an attempt to obfuscate malicious code. The 'PDF_JS_LARGE_COMMENT_PADDED_EVAL' heuristic firing suggests a stager designed to download and execute a secondary payload. The ClamAV detection of 'Pdf.Exploit.Agent-36086' further supports this, pointing to a known exploit. No specific family could be identified, but the pattern is consistent with a PDF-based downloader.

Heuristics 7

  • ClamAV: Pdf.Exploit.Agent-36086 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Exploit.Agent-36086
  • eval() call high PDF_EVAL
    eval() found — commonly used for obfuscated exploit execution (matched inside decoded stream)
  • Large comment-padded JavaScript eval stager high PDF_JS_LARGE_COMMENT_PADDED_EVAL
    PDF JavaScript contains a very large stream padded with long random-looking block comments around String.fromCharCode and eval. This is an exploit-kit obfuscation shape used to bury a decoder and recovered stage inside noise, not normal PDF form automation.
  • 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. (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 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0006_000.js
352b477964c70bfb11ade5f25ea3c24cadf826d45bde16df4b89cc06db0ffc35
pdf-javascript-stream PDF /JS object 6 at offset 0x143 426010 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s). Carved artifact contains 42 long base64-like blob(s).