Malicious PDF — malware analysis report

Static analysis result for SHA-256 52b40d0ff6944663…

MALICIOUS

PDF

23.6 KB
MD5: 888b4c5e290574d1f50eddf8f6e1eb1c SHA-1: 308b3f0e71b4a5c474bffd72b5a8d362f2a29a52 SHA-256: 52b40d0ff6944663f931adad981cd290ce89fe64ea4c85e8913ee9b591c3cba6
120 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1059.007 JavaScript

This PDF file contains embedded JavaScript that is obfuscated and likely exploits a vulnerability to download and execute a second-stage payload. The ML classifier strongly indicates maliciousness, and the presence of JavaScript exploit cluster heuristics further supports this. The deobfuscated JavaScript is too truncated to determine the exact payload or delivery mechanism, but the overall pattern suggests a downloader.

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
ba02b2baef0af1a9fc369e384b639f49a4452a51edafdc638a1e03e504fa4cca
pdf-javascript-stream PDF /JS object 99 at offset 0x548D 8669 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
b2044bfb66a1bae1606c21bfec643c3f8b193a0c30e36b81842e87c4d30ab28a
deobfuscated-js PDF JavaScript deobfuscation pass 40262 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).