Malicious PDF — malware analysis report

Static analysis result for SHA-256 0a6df929778cd23d…

MALICIOUS

PDF

6.8 KB
MD5: eda9a31ee02aa0872aa210b0448f041b SHA-1: 38447a4c36eac7ba291450a2b1cf5ed166eaa8d8 SHA-256: 0a6df929778cd23d7cddcd3d3adad5b75dbf3185ff81d3f50ecdada1aa4eaa7a
226 Risk Score

Malware Insights

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

The PDF sample utilizes JavaScript to exploit CVE-2014-0496, a vulnerability related to app.addToolButton/removeToolButton. The embedded JavaScript, after deobfuscation, contains logic to download a second-stage payload from the URL http://armscyerouzyuku.thecolourista.com/world/avoidance_water_flour.txt?e=9. This indicates a downloader or dropper functionality.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 9

  • app.addToolButton/removeToolButton — CVE-2014-0496 critical CVE exact CVE_2014_0496
    PDF JavaScript combines app.addToolButton() and app.removeToolButton() with heap-spray shellcode markers — the public Adobe Reader/Acrobat ToolButton use-after-free exploit shape for CVE-2014-0496. (identified after JavaScript deobfuscation)
  • 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.
  • PDF JavaScript shellcode contains an embedded download URL high PDF_JS_SHELLCODE_DOWNLOAD_URL
    Decoded PDF JavaScript shellcode contains a hardcoded http(s) URL stored as little-endian %uXXXX Unicode escapes. Reader exploit shellcode embeds the second-stage fetch URL this way and pulls it down with a urlmon/URLDownloadToFile-style download-and-execute (commodity downloader behaviour rather than a specific Acrobat CVE).
  • 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.
  • XFA form low PDF_XFA
    PDF uses XML Forms Architecture — can contain script logic
  • AcroForm button with action trigger low PDF_ACROFORM_BUTTON
    PDF contains a /Btn form field together with a SubmitForm/URI/Launch/JS trigger — this is the building block of fake 'Download' or 'Open' button overlays used in PDF phishing lures
  • 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://armscyerouzyuku.thecolourista.com/world/avoidance_water_flour.txt?e=9
    • http://ns.adobe.com/xdp/
    • http://www.xfa.org/schema/xci/2.8/
    • http://www.xfa.org/schema/xfa-template/2.5/

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0003_000.js
2f1d59e55b18d1ce5e2f2d10538318704e7c41be980d9137f4d47641dce829cc
pdf-javascript-stream PDF /JS object 3 at offset 0x409 15530 bytes
base26_stage_000.js
b8b4f69f2287653959af7aa4db1cf4a71c8ca0abd17ae1f3e6a7d1cd34c46f01
deobfuscated-js base26-decoded JavaScript (decompressed) at offset 0x60D 5913 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 44 eval/decoder/string-building token(s).