Malicious PDF — malware analysis report

Static analysis result for SHA-256 0487ac5ced0cf379…

MALICIOUS

PDF

20.1 KB
MD5: 495481265b5c01d960dec0530ca23fb0 SHA-1: eada7abe4f83f523f386c5f97ce750162ba8095a SHA-256: 0487ac5ced0cf379ec1ffc9650ae4bcc55174e26d307ecbc8f4b05104236b31a
120 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 is heavily obfuscated using String.fromCharCode. The ML classifier and exploit cluster heuristics strongly indicate malicious intent. The JavaScript is likely responsible for downloading and executing a secondary payload, a common technique for initial compromise.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9994

Heuristics 7

  • 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.
  • 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)
  • PDF paints image(s) but contains no text operators info PDF_IMAGE_ONLY_LURE
    PDF has 1 image XObject(s) and the content stream contains no text-emitting operators (BT/ET, Tj, TJ, ', ") in either raw bytes or decompressed streams — this is the screenshot-as-PDF pattern used to bypass text-based scanners and to deliver instructions purely through rendered pixels. It is informational unless paired with invisible links or risky URI context.
  • 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.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://www.w3.org/1999/02/22-rdf-syntax-ns#

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0099_000.js
e707868f52fa6792fa3a44cc7697e9f4f9e39120230a518b9b8c1503781128d9
pdf-javascript-stream PDF /JS object 99 at offset 0x479A 15425 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 eval/decoder/string-building token(s).