Malicious PDF — malware analysis report

Static analysis result for SHA-256 12056d513d080257…

MALICIOUS

PDF

29.8 KB
MD5: de1e57e12839ada016c8cdb91a9c3565 SHA-1: 70fb3ab3267f3f9e2a837e3c0b138293040b8d9c SHA-256: 12056d513d080257692b41a06ebbe228a37f8e05e7d9aefaa79be24d916da14d
174 Risk Score

Malware Insights

MITRE ATT&CK
T1059.007 JavaScript T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The PDF file contains embedded JavaScript that is heavily obfuscated using String.fromCharCode. This script is designed to exploit a vulnerability within the PDF reader, likely to download and execute a secondary payload from the provided URLs. The presence of embedded Flash (RichMedia) and XFA forms further indicates a complex exploit chain. The ML classifier strongly indicates maliciousness.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 9

  • 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.
  • RichMedia (Flash) high PDF_RICHMEDIA
    PDF contains /RichMedia (Adobe Flash) which is a historic exploit vector
  • 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.
  • Embedded file low PDF_EMBEDDED
    PDF embeds a file attachment — could carry an executable or another weaponised document as a nested payload
  • XFA form low PDF_XFA
    PDF uses XML Forms Architecture — can contain script logic
  • 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)
  • 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://code.flashdynamix.com/AES/aes-decrypt.php
    • http://code.flashdynamix.com/AES/aes-encrypt.php
    • http://ns.adobe.com/xdp/
    • http://www.xfa.org/schema/xci/2.6/
    • http://www.xfa.org/schema/xfa-template/2.6/
    • 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/xap/1.0/sType/ResourceRef#
    • http://adobe.com/AS3/2006/builtin

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
test.swf
4d4d42d908c48737d0cbe1f33c14f197803950e6ff47f9c0f13e1d51a231494d		 pdf-embedded-file PDF EmbeddedFile object 16 at offset 0x8EE 53991 bytes
javascript_obj0006_000.js
2e17869d7ef8187727a96cce06c526641a12678101093d2096d635711240ad9c		 pdf-javascript-stream PDF /JS object 6 at offset 0x106 11582 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 239 eval/decoder/string-building token(s).

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