Malicious PDF — malware analysis report

Static analysis result for SHA-256 53f8e8fc4706824c…

MALICIOUS

PDF

118.7 KB
MD5: 06a90e74d9bad6fa6cc483922f758e18 SHA-1: b99349d8ce75afb0f90e7384d1f6f1f49e9c004d SHA-256: 53f8e8fc4706824cfee166d0857d9a0566e7bed9959897f9bf78c40caade27e9
166 Risk Score

Malware Insights

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

The file is a PDF containing embedded JavaScript, as indicated by multiple heuristic firings including PDF_JAVASCRIPT, PDF_JS, and PDF_EVAL. The critical ClamAV detection and the presence of a large, comment-padded JavaScript eval stager strongly suggest exploitation. The embedded JavaScript file, 'javascript_obj0006_000.js', is likely responsible for downloading and executing a second-stage payload, which is a common technique for initial access and further compromise.

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
166f844ff754cf65852798d893a56badc5dde32a07b45b045dd7229ec2ed9967
pdf-javascript-stream PDF /JS object 6 at offset 0x143 627419 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).