Malicious PDF — malware analysis report

Static analysis result for SHA-256 a03d99c45878384d…

MALICIOUS

PDF

15.7 KB
MD5: 924dc48d6bb42e48809ac9da9317b9b7 SHA-1: a70a0e3eadbcd427c1e8c772161578c5d357da04 SHA-256: a03d99c45878384d53aa17ab8c430247006ffcbdf527d8c98fd31615574082d7
166 Risk Score

Malware Insights

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

The PDF file contains embedded JavaScript that utilizes `eval()` and `String.fromCharCode()`, indicating an attempt to obfuscate malicious code. The presence of a 'large comment-padded JavaScript eval stager' heuristic firing, along with ClamAV detecting it as 'Pdf.Exploit.Agent-36086', strongly suggests it's designed to exploit a PDF vulnerability. The primary goal appears to be the execution of a second-stage payload, as implied by the stager heuristic.

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
fd6dd32c15c6f0619486296dfbd518536f71242744647bae7cad77dc2e2d1770
pdf-javascript-stream PDF /JS object 6 at offset 0x143 425525 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).