Malicious PDF — malware analysis report

Static analysis result for SHA-256 b9a0272ec856f485…

MALICIOUS

PDF

118.6 KB
MD5: e0ea0185868f2b46b05b9c9d7f5aaf23 SHA-1: 88cc45cfe1f2665a7f0e3483b1327d98405755a6 SHA-256: b9a0272ec856f485ccaad17a3873a2120ab4de25783de6b68dc9aeb45d41f362
196 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 JavaScript/JScript T1204.002 Malicious File

The PDF file contains embedded JavaScript, including calls to eval() and String.fromCharCode, indicating an attempt to obfuscate and execute malicious code. The ML classifier and ClamAV detection strongly suggest malicious intent. The primary attack vector appears to be exploiting PDF vulnerabilities to run this script, which is likely a stager for further malicious activity.

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
cc69043f0761749062b5b44b72db7d5816b10095f678ff70e05fd46720375b93
pdf-javascript-stream PDF /JS object 6 at offset 0x143 626620 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).
stream_001_off0001d6ce.bin
478bbab7163a4784ba4fbfbc8e8f783e4290f477aa5df551d8d70644e9b4eb7f
decompressed-pdf-stream PDF FlateDecoded stream at offset 0x1D6CE 300 bytes