Malicious PDF — malware analysis report

Static analysis result for SHA-256 fb809a7b8a89979f…

MALICIOUS

PDF

118.6 KB
MD5: a080ba6824845808ff876530484f5f11 SHA-1: d74589eb970be0061f1506d7d1a8c3ec457face5 SHA-256: fb809a7b8a89979fd93710b504177201fb794b86c7e91474337d76db653559bf
166 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 JavaScript/JScript T1566.002 Spearphishing Attachment T1204.002 Malicious File

The file is identified as malicious by ClamAV with the signature Pdf.Exploit.Agent-36086. Static analysis revealed embedded JavaScript with eval() calls and String.fromCharCode usage, indicating an attempt to obfuscate and execute malicious code. The presence of a large comment-padded JavaScript eval stager further supports this. The primary attack vector appears to be exploiting a PDF vulnerability to run this script.

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
6e664810fc372fb472d0b7070c99f20515bbb7602d1bf358b46ac73e3ddc8c59
pdf-javascript-stream PDF /JS object 6 at offset 0x143 626878 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).