Malicious PDF — malware analysis report

Static analysis result for SHA-256 247b45f850f4b4e0…

MALICIOUS

PDF

118.5 KB
MD5: 71025eb78ac0e69079e6951b8a3ee498 SHA-1: a83ccdf700f50cfdc9d924a8501ef843b66745a2 SHA-256: 247b45f850f4b4e0f2e50f99f34104330796ae270f1a5de0a4a4997a3dcc6a6c
166 Risk Score

Malware Insights

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

The PDF file contains multiple JavaScript streams, including one with a large comment-padded eval stager. The presence of eval() and String.fromCharCode() indicates obfuscated code execution. ClamAV detection as 'Pdf.Exploit.Agent-36086' strongly suggests an exploit is present. The primary function of the embedded JavaScript appears to be the download and execution of a secondary payload, as indicated by the heuristic firings and the nature of PDF exploits.

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
22b911086a9208313959136a18df2d5d4a6384f1ea81c7ab959380c3c9731a7b
pdf-javascript-stream PDF /JS object 6 at offset 0x143 627086 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).