Malicious PDF — malware analysis report

Static analysis result for SHA-256 9dc35f75f5d60bb6…

MALICIOUS

PDF

15.7 KB
MD5: 0e8fd97cde4558c132a8a480786c41ac SHA-1: 25c9bedd837102eed989cc737dafa620e937e7b9 SHA-256: 9dc35f75f5d60bb6134009609fc7103bff9ca7a256fa6b72f36d88d2a0ed4ad1
166 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1204.002 Malicious File T1566.001 Spearphishing Attachment T1071.001 Web Protocols

The PDF file contains embedded JavaScript, indicated by multiple heuristic firings including 'PDF_JAVASCRIPT', 'PDF_JS', and critically 'PDF_JS_LARGE_COMMENT_PADDED_EVAL'. The 'eval()' call within the JavaScript stream suggests code execution. The ClamAV detection 'Pdf.Exploit.Agent-36086' further confirms malicious intent. The primary function of the embedded JavaScript appears to be downloading and executing a second-stage payload, as suggested by the large size of the extracted JavaScript file and the presence of obfuscation indicators.

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
f4cfd5627b496644b72757fc292631921b5cccc434b3fe7d1b2e9a1c1fb31bc4
pdf-javascript-stream PDF /JS object 6 at offset 0x143 424172 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).