Malicious PDF — malware analysis report

Static analysis result for SHA-256 a162932c3e51cdff…

MALICIOUS

PDF

118.6 KB
MD5: 4d8eac3b30fd6e458c51942814423ab3 SHA-1: 0ad366bf57bffae0c6e895b4523bc97e9d49615b SHA-256: a162932c3e51cdff5fa4ded13da1de432a89cbabe26f20ed8d6fa8e59d9d698a
166 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell

The PDF file contains multiple high-severity heuristic firings related to JavaScript execution, including eval() calls and a large comment-padded eval stager. The ClamAV detection 'Pdf.Exploit.Agent-36086' further confirms its malicious nature. The embedded JavaScript streams, particularly 'legacy_pdfkit_stage_000.js', are heavily obfuscated but indicate an intent to download and execute a secondary payload, a common technique for initial access or further infection.

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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0006_000.js
de619245e78ac55e321356191c4a67bbe17141bf6274d4dacd59c7bb4a82dea7
pdf-javascript-stream PDF /JS object 6 at offset 0x143 627029 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).
legacy_pdfkit_stage_000.js
1dd47739b1cb5e5b40335b5907cee29ad49166255b5d3a5384e21a607eaa0c80
deobfuscated-js double percent-decoded annotation JavaScript at offset 0x143 262144 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 614 long base64-like blob(s).