Malicious PDF — malware analysis report

Static analysis result for SHA-256 9dc074eb6f9b851f…

MALICIOUS

PDF

118.6 KB
MD5: 93a45ccaa253e0fc2261937c3a8df493 SHA-1: 1dff9e0c3433b70d629256d2593bd80bdff132d6 SHA-256: 9dc074eb6f9b851fff1b408f5b9c065638763e4ddfc53b9d02f5ec1461b7f88d
166 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1204.002 Malicious File T1566.001 Spearphishing Attachment T1071.001 Web Protocols

The file is a PDF containing embedded JavaScript, as indicated by multiple PDF-specific heuristics including 'PDF_JAVASCRIPT', 'PDF_JS', and 'PDF_EVAL'. The 'PDF_JS_LARGE_COMMENT_PADDED_EVAL' heuristic suggests a stager mechanism. ClamAV detection as 'Pdf.Exploit.Agent-36086' confirms its malicious nature. The JavaScript is heavily obfuscated, but the presence of eval() and fromCharCode suggests dynamic code execution, likely to download and execute a secondary payload.

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
8b38f0b92766d0b6aee91bbe12f0db16391628d9b49aae30632ee015d7d79883
pdf-javascript-stream PDF /JS object 6 at offset 0x143 627393 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
851521c7c2cf5296e4e0780c2071c9960001b170b09ee79d07b02ec57829a9e6
deobfuscated-js double percent-decoded annotation JavaScript at offset 0x143 262118 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 570 long base64-like blob(s).