Malicious PDF — malware analysis report

Static analysis result for SHA-256 5336db96187f0c1b…

MALICIOUS

PDF

15.7 KB
MD5: 6ed7f4b50ee0c7a02c326b7ed2acd6be SHA-1: f04215ac0265cbbd10cae05c9d82f31c6cdfb4c2 SHA-256: 5336db96187f0c1b4a5c12849297d9a78e387570225a7b76a4c04dca95d11ddd
166 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 JavaScript/JScript

The PDF file contains embedded JavaScript, indicated by multiple heuristic firings including PDF_JAVASCRIPT, PDF_JS, and PDF_EVAL. The presence of a 'Large comment-padded JavaScript eval stager' suggests an attempt to obfuscate malicious code. ClamAV detection as 'Pdf.Exploit.Agent-36086' further confirms its malicious nature. The JavaScript streams are large and heavily obfuscated, making it difficult to determine the exact payload, but the overall pattern points to exploit-based delivery of a secondary malicious component.

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
16756a3b5db388f391a01efe23356ad18d341be7a06a0ae094915bfef8a339f7
pdf-javascript-stream PDF /JS object 6 at offset 0x143 425320 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
3b9ccb0489ff59553f869aecb78933022b2fba9c9ff17b456e0744542c613f51
deobfuscated-js double percent-decoded annotation JavaScript at offset 0x143 262144 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 584 long base64-like blob(s).