Malicious PDF — malware analysis report

Static analysis result for SHA-256 2cb1aa138c747ab6…

MALICIOUS

PDF

118.5 KB
MD5: f998278da8ec38e3e6d6456391c4072c SHA-1: 5b3b174b1a872190b33e5ad83222ffc4f41f7d3f SHA-256: 2cb1aa138c747ab69bc0dd4885eb55c11d4fef6eb17611c98e3bf535993dbb9e
196 Risk Score

Malware Insights

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

This PDF file was flagged by multiple high-severity heuristics, including PDF_JAVASCRIPT, PDF_JS, PDF_EVAL, and PDF_JS_LARGE_COMMENT_PADDED_EVAL, indicating the presence of obfuscated JavaScript designed to execute code. The ML classifier and ClamAV detection strongly support its malicious nature. The embedded JavaScript, likely a stager, is designed to download and execute a second-stage payload, as suggested by the 'eval()' calls and the ML classifier's output. The ClamAV detection name 'Pdf.Exploit.Agent-36086' is included as a primary IOC.

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 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0006_000.js
20338cd24d292363730412ec8a669942aead958711abfaa84b993b5327c3f2c7
pdf-javascript-stream PDF /JS object 6 at offset 0x143 627119 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).