Malicious PDF — malware analysis report

Static analysis result for SHA-256 b5b0a62a035bb927…

MALICIOUS

PDF

15.7 KB
MD5: 9c06c1cf12920012bfb3cfea7ee70a80 SHA-1: 8b708675597b512d470c2649ce10b59b38103004 SHA-256: b5b0a62a035bb92713e5ad52fc386e0d355f974e8f13376df14e59960ecfa3a9
166 Risk Score

Malware Insights

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

The sample is a PDF containing obfuscated JavaScript, indicated by multiple PDF-specific heuristic firings including 'PDF_JAVASCRIPT', 'PDF_JS', 'PDF_EVAL', and 'PDF_JS_LARGE_COMMENT_PADDED_EVAL'. The ClamAV detection 'Pdf.Exploit.Agent-36086' strongly suggests it's a known exploit. The embedded JavaScript, although not fully detailed here, is the likely mechanism for delivering a secondary payload, as suggested by the 'eval' and 'fromCharCode' calls.

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
8ff4d5bc19d3ac0d0058ee48055f920a06204dc49b42be75d1c455050a6e1ebc
pdf-javascript-stream PDF /JS object 6 at offset 0x143 425402 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).