Malicious PDF — malware analysis report

Static analysis result for SHA-256 123b845bc68c5b84…

MALICIOUS

PDF

6.8 KB
MD5: 791e104573a81de189d9903a7b75a89c SHA-1: 9b62e372a941b9dc631d1e1fe50387ad457c04dc SHA-256: 123b845bc68c5b84ff7983998c807a5abc801d69d667a188bb715709de8e7585
226 Risk Score

Malware Insights

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

This PDF file exploits CVE-2014-0496 using embedded JavaScript to download a secondary payload from the URL http://tilannut.xollus.com/world/emancipate-main_managing.txt?e=9. The JavaScript is heavily obfuscated but the exploit and download URL are clearly identified by heuristics. The ML classifier also strongly indicates maliciousness.

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://tilannut.xollus.com/world/emancipate-main_managing.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
d5a09a8b483ce3783b5653eeea9ce30cd8009edb2870847b5638718334cb6295		 pdf-javascript-stream PDF /JS object 3 at offset 0x409 15454 bytes
base26_stage_000.js
6fc7312a0387e23bf6c6ec7aed610010a12f2a036c092e0a29eaa693f1c7c15f		 deobfuscated-js base26-decoded JavaScript (decompressed) at offset 0x60D 5883 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 44 eval/decoder/string-building token(s).

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