Malicious PDF — malware analysis report

Static analysis result for SHA-256 73257a7f0109f594…

MALICIOUS

PDF

44.9 KB
MD5: 590d23a8fd66c8c0f5565ce2568cb515 SHA-1: 28f017342fb0d788ddb32361449fe693a97f5c34 SHA-256: 73257a7f0109f594c168fe159f9d2447542f4c25c51e9c3e7a05ead31868e397
236 Risk Score

Malware Insights

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

The PDF file contains obfuscated JavaScript within an XFA form, a known technique for exploiting PDF vulnerabilities. The embedded JavaScript is heavily obfuscated, but the presence of PDF_XFA and PDF_OBFUSCATED_NAME_OBJECT heuristics strongly suggests an exploit attempt. The primary function of the script appears to be downloading and executing a secondary payload, indicated by the exploit cluster firing. While the specific payload and delivery mechanism are not detailed, the overall pattern points to a malicious document intended for initial compromise.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9615

Heuristics 7

  • Hex-obfuscated scripting name object critical PDF_OBFUSCATED_NAME_OBJECT
    A PDF name object that drives script execution (/JavaScript or /JS) is written with #XX hex escapes to hide it from string-based scanners — e.g. /J#61v#61S#63r#69p#74 decoding to /JavaScript. Legitimate PDF producers always write these names literally; hex-encoding an executable name is a deliberate evasion used by exploit-kit and dropper PDFs.
  • 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.
  • ClamAV: Heuristics.PDF.ObfuscatedNameObject critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Heuristics.PDF.ObfuscatedNameObject
  • 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
  • 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://ns.adobe.com/xdp/
    • http://www.xfa.org/schema/xci/2.6/
    • http://www.xfa.org/schema/xfa-template/2.6/

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0012_000.js
1399137859aca0b87eb0120f00c513f771e751e7fdcbf4959a4ae75fe43117dd		 pdf-javascript-stream PDF /JS object 12 at offset 0xA1F9 3381 bytes

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