Malicious PDF — malware analysis report

Static analysis result for SHA-256 dcab1aad935e9fb6…

MALICIOUS

PDF

118.5 KB
MD5: ca53de5d6c78670fd46e07e50e880bfb SHA-1: f875713cd12bbf2d197f7f1b5c9be794ad2c1978 SHA-256: dcab1aad935e9fb634ba01f72f880e188bc4a547451fa3acc14049f8e3a1a6cd
166 Risk Score

Malware Insights

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

The PDF file contains embedded JavaScript, indicated by multiple heuristic firings including 'PDF_JAVASCRIPT', 'PDF_JS', and 'PDF_EVAL'. A critical heuristic 'CLAMAV_DETECTION' identified the file as 'Pdf.Exploit.Agent-36086'. The presence of 'eval()' and 'String.fromCharCode' within the JavaScript stream suggests obfuscation and dynamic code execution, likely to download and execute a second-stage payload. The 'Long encoded blob, Script obfuscation indicators' heuristic further supports this. No specific family could be confidently identified.

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
d4e6c00d6cab70ace2f53256aa70ced3e899b98502c2d7f9db5c6d463a721937
pdf-javascript-stream PDF /JS object 6 at offset 0x143 626889 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).