Malicious PDF — malware analysis report

Static analysis result for SHA-256 21525d5b93a3ef98…

MALICIOUS

PDF

118.6 KB
MD5: c06df8937b6951a8ecd84152e1a11e89 SHA-1: b46017ba221b1ad9210804fdecce7b3238fb9b64 SHA-256: 21525d5b93a3ef986c4eacb2247d1ca197026fc2e9d6c4ac691705f72404466b
166 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 JavaScript T1566.002 Spearphishing Attachment

The PDF file contains embedded JavaScript, indicated by multiple heuristic firings including PDF_JAVASCRIPT, PDF_JS, and PDF_EVAL. The 'Large comment-padded JavaScript eval stager' heuristic suggests a common technique for obfuscating malicious code. ClamAV detection as 'Pdf.Exploit.Agent-36086' further confirms its malicious nature. The primary attack pattern involves exploiting PDF vulnerabilities to execute arbitrary code, likely for further payload delivery.

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
0cdbcad3d1b7fe80886645cc672249d1096694596963543ff3b375b32ce2802c
pdf-javascript-stream PDF /JS object 6 at offset 0x143 626820 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).