Malicious PDF — malware analysis report

Static analysis result for SHA-256 051048e90d1e096b…

MALICIOUS

PDF

118.6 KB
MD5: ead664bedab77b0357b514b71cc2502f SHA-1: b67b65e94b59229a47720bc6830884ad693a25dd SHA-256: 051048e90d1e096bf41f4e8b722b745a2a5c8d3ae898d1d0467dbb69dc3417dd
256 Risk Score

Malware Insights

MITRE ATT&CK
T1059.007 JavaScript T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The PDF file contains embedded JavaScript that utilizes eval() and String.fromCharCode() functions, indicating an attempt to obfuscate malicious code. This JavaScript is likely responsible for downloading and executing a secondary payload, as suggested by the 'PDF JavaScript exploit cluster' and 'ML_NYX_PDF_MALICIOUS' heuristics. The ClamAV detection 'Pdf.Exploit.Agent-36086' further confirms its malicious nature, pointing towards a known exploit.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 8

  • PDF JavaScript exploit cluster critical PDF_JS_EXPLOIT_CLUSTER
    PDF combines an executable JavaScript/action surface with exploit staging indicators such as eval/unescape/fromCharCode, XFA script content, or a related CVE pattern. Benign form JavaScript remains low-severity, but this correlated cluster is high-confidence malicious behavior.
  • 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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0006_000.js
14b3576bc0490a29f283c0435bdfda6c35faaa4f8b3fe7b9df70bbe116558c24
pdf-javascript-stream PDF /JS object 6 at offset 0x143 627196 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).
stream_001_off0001d6c9.bin
ca55d4675c1e029bcdd50821fe50dd5db20270b43f14b636db0bee464d1edcf2
decompressed-pdf-stream PDF FlateDecoded stream at offset 0x1D6C9 300 bytes