Malicious PDF — malware analysis report

Static analysis result for SHA-256 b65eba955e779952…

MALICIOUS

PDF

118.5 KB
MD5: aafb16bd80ee4c35b51573a3ab527666 SHA-1: a20d21baf7a25c82116a89415c9f45df2d984dba SHA-256: b65eba955e7799528f573864d21e7af04d5831b27b126dc8ec9677b90d58e443
166 Risk Score

Malware Insights

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

The PDF file contains embedded JavaScript, indicated by multiple heuristic firings including 'PDF_JAVASCRIPT', 'PDF_JS', and 'PDF_EVAL'. The critical 'CLAMAV_DETECTION' heuristic identified it as 'Pdf.Exploit.Agent-36086'. The presence of 'eval()' calls and 'String.fromCharCode' within the JavaScript stream suggests obfuscation and dynamic code execution, typical for downloading and executing further malicious content. The extracted file 'javascript_obj0006_000.js' likely contains the malicious script. The overall attack pattern points to a malicious PDF designed to exploit vulnerabilities and deliver a payload.

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
4068332d16f12322b7bfdd9e3470a8cdb7c48ab96009ebcd3685134032e0f144
pdf-javascript-stream PDF /JS object 6 at offset 0x143 627079 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).