Malicious PDF — malware analysis report

Static analysis result for SHA-256 62bd844b3e1ea57b…

MALICIOUS

PDF

48.2 KB Created: 2010-05-04 08:37:44 +08:00 Authoring application: Acrobat Web Capture 7.0
MD5: f02af061db5b501392231adcdf4d7bc5 SHA-1: 0dbf1aba2c2d4d895ee6d746f6c78592f0057bb4 SHA-256: 62bd844b3e1ea57b2a886a396cffa9369ff33e003f64f461cd8970b58d3b6bfa
176 Risk Score

Malware Insights

MITRE ATT&CK
T1059.007 JavaScript T1203 Exploitation for Client Execution

This PDF file contains embedded JavaScript that utilizes eval() and String.fromCharCode() for obfuscation. The script decodes a string which is then evaluated, likely to download and execute a second-stage payload. The ML classifier strongly indicates maliciousness, and the JavaScript exploit cluster confirms the exploitation of PDF vulnerabilities.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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.
  • eval() call high PDF_EVAL
    eval() found — commonly used for obfuscated exploit execution (matched inside decoded stream)
  • Suspicious extracted artifact medium 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.
  • 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)
  • 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 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0037_000.js
e93f32651195259b64d1a1cedc9097e7cb099d84a8994f3b6627e13d7782b193		 pdf-javascript-stream PDF /JS object 37 at offset 0xA35 16095 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 14 eval/decoder/string-building token(s). Carved artifact contains 4 long base64-like blob(s). Carved artifact contains 6 long hex-escaped blob(s).

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