Malicious PDF — malware analysis report

Static analysis result for SHA-256 18ed37973771014d…

MALICIOUS

PDF

19.3 KB Created: 2012-09-17 23:33:20 +04:00 Authoring application: Adobe Acrobat 10.0 (via Acrobat Web Capture 10.0)
MD5: ce5bd4219437b2286b160674476f763c SHA-1: 7ff006d7d899ed5ccd5d0ee230d9975678babb05 SHA-256: 18ed37973771014dd85261e3417c89f2b858bea2f0fac240ff0be5c07c615ad7
118 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 obfuscated using String.fromCharCode. The JavaScript is designed to download and execute a second-stage payload, as indicated by the PDF_JS_EXPLOIT_CLUSTER heuristic. The reconstructed JavaScript string 'xx='b';' is the initial part of the obfuscated code, suggesting a downloader functionality. The ML classifier strongly indicates maliciousness.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 6

  • 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.
  • 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/
    • http://www.iec.ch

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0019_000.js
059c1e1d79f87eadc62c9a6882fcf39cf70c581cf3d5c5cdef271d18f5134c02		 pdf-javascript-stream PDF /JS object 19 at offset 0x2DE 8208 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 eval/decoder/string-building token(s). Carved artifact contains 10 long base64-like blob(s).
icc_00_off000029a9.icc
653b586c4707574ffcd648ba35494daed2c76ceafcf4c07d315ed961b1dc347f		 pdf-icc-profile PDF ICC profile at offset 0x29A9 408 bytes
icc_01_off00002c44.icc
2b3aa1645779a9e634744faf9b01e9102b0c9b88fd6deced7934df86b949af7e		 pdf-icc-profile PDF ICC profile at offset 0x2C44 3144 bytes

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