Malicious PDF — malware analysis report

Static analysis result for SHA-256 789f0d998ca0eb31…

MALICIOUS

PDF

118.7 KB
MD5: d82a43fd50bb26cbe4a4ac59c0fccf01 SHA-1: 9f7026d2e9d081b966edc2638ae8350f6e863e48 SHA-256: 789f0d998ca0eb314fc7d432f35fe87a123dd10a639dd0c4b19a85ab4dff5dff
256 Risk Score

Malware Insights

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

This PDF file contains obfuscated JavaScript that utilizes eval() and String.fromCharCode() functions, indicative of an exploit attempting to download and execute a secondary payload. The critical PDF_JS_EXPLOIT_CLUSTER and ML_NYX_PDF_MALICIOUS heuristics, along with ClamAV detection as Pdf.Exploit.Agent-36086, strongly suggest malicious intent. The JavaScript's primary function appears to be downloading and executing a further stage, likely to compromise the user's system.

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
8b3e73332f3e214fe634607d42afc5dbf50f760984640f475415642bcc5b1ec5
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_off0001d71c.bin
c6bea59500fac83dd4e6b8144c8ce86006b3cf360a3af7566d1e1a279b9ed04f
decompressed-pdf-stream PDF FlateDecoded stream at offset 0x1D71C 300 bytes