Malicious PDF — malware analysis report

Static analysis result for SHA-256 65db2e3a05ec24fd…

MALICIOUS

PDF

118.6 KB
MD5: c1b2cb19c3ead77f63493d04ba2daad5 SHA-1: f2b76464af0355fb45a97e20a94f289d2da939b4 SHA-256: 65db2e3a05ec24fdb4d4eae97f5c85be5374c661be3733360e924c7b5c1b2bdd
256 Risk Score

Malware Insights

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

This PDF file contains embedded JavaScript that utilizes eval() and String.fromCharCode, indicating an attempt to obfuscate malicious code. The high ML and ClamAV scores, along with the 'PDF JavaScript exploit cluster' and 'Large comment-padded JavaScript eval stager' heuristics, strongly suggest the JavaScript is designed to exploit a vulnerability and download a secondary payload. The ClamAV detection name 'Pdf.Exploit.Agent-36086' is included as an IOC.

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
b03cdf4a16ee6e3f8a7a5e2c2134d594b2da34ef1fa04a31dd0e4a283127596f
pdf-javascript-stream PDF /JS object 6 at offset 0x143 626961 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_off0001d6c1.bin
1aef68994df1547b18f07e9aebf73b1a9d55d3f3ee366cb08c032c1e2ac03686
decompressed-pdf-stream PDF FlateDecoded stream at offset 0x1D6C1 300 bytes