Malicious PDF — malware analysis report

Static analysis result for SHA-256 fe8d555c883edd7c…

MALICIOUS

PDF

15.8 KB
MD5: e32d020d4cdecf23512778b4bc6a3582 SHA-1: 901a148feba5525550e1e6ef04fbc94f1cc19ea7 SHA-256: fe8d555c883edd7c6c687e087170ad4ec3caf2b714e85e1be354045a3da81abe
196 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1059.007 JavaScript

The PDF file was flagged by multiple high-severity heuristics, including PDF_EVAL and PDF_JS_LARGE_COMMENT_PADDED_EVAL, indicating the presence of obfuscated JavaScript. ClamAV detected this file as 'Pdf.Exploit.Agent-36086'. The embedded JavaScript streams, particularly 'legacy_pdfkit_stage_000.js', likely contain code to download and execute a second-stage payload, a common technique for initial access.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

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
a1995b30226dee295156a13bcc263547501bb59c813325abbcd5cce02b969e5a
pdf-javascript-stream PDF /JS object 6 at offset 0x143 425595 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
c628c1fe2f7469a1e0f2a79d8940ce823ea1259ca93c72799837fb9b477c4d92
deobfuscated-js double percent-decoded annotation JavaScript at offset 0x143 262144 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 559 long base64-like blob(s).