Malicious PDF — malware analysis report

Static analysis result for SHA-256 542a8c33c2261c6c…

MALICIOUS

PDF

23.6 KB
MD5: 7c39236efc79f8775ad042900f211cbd SHA-1: 2af75d5ce463941696d9cb0a42b0eca476360df5 SHA-256: 542a8c33c2261c6cf777ae67d6843e69d6d96a80f6a759e931481b003d19b496
120 Risk Score

Malware Insights

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

The PDF contains embedded JavaScript, flagged by multiple heuristics including 'PDF_JAVASCRIPT', 'PDF_JS', and 'PDF_JS_EXPLOIT_CLUSTER'. The ML classifier also strongly indicated maliciousness. The deobfuscated JavaScript likely contains code to download and execute a secondary payload, as indicated by the 'EXTRACTED_FILE_STATIC_TRIAGE' heuristic which noted 'Long encoded blob, Script obfuscation indicators'. The presence of JavaScript actions and embedded JS streams points to an attempt to exploit vulnerabilities within the PDF reader to achieve code execution.

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#
    • http://ns.adobe.com/xap/1.0/
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/pdf/1.3/

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0099_000.js
d18451693bc58415ae5b1e61dc5646ead7cea7c90f9052ddb9035858232a8926
pdf-javascript-stream PDF /JS object 99 at offset 0x548D 8717 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s). Carved artifact contains 9 long base64-like blob(s).
deobfuscated.js
c49bcf88307dba1fcfc2f4d03e6fc2d8bf4a7753b63dbf438f1044169574570c
deobfuscated-js PDF JavaScript deobfuscation pass 40166 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 4 eval/decoder/string-building token(s). Carved artifact contains 18 long base64-like blob(s).