Malicious PDF — malware analysis report

Static analysis result for SHA-256 7939ede530f8b00c…

MALICIOUS

PDF

37.7 KB
MD5: 2d0f010eb1e1622b83a906bd5645dd99 SHA-1: 04938a579e1f41e06e5b44c76e3c10c4f10210fb SHA-256: 7939ede530f8b00ceff2fd54c3355efb1b9a5aa57afb31630071291575a7bcd8
186 Risk Score

Malware Insights

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

This PDF file contains embedded JavaScript that is heavily obfuscated using String.fromCharCode and concatenation. The script appears to be designed to download and execute a second-stage payload from the URL http://www.flashandmath.com. The ML classifier strongly indicates maliciousness, and the presence of JavaScript exploit cluster heuristics further supports this. The embedded Flash object also suggests a potential exploit vector.

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
  • ASCIIHexDecode filter (with exploit indicators) medium PDF_FILTER_HEX
    Hex-encoding filter present alongside exploit delivery indicators — often used to hide payload or shellcode bytes
  • 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
  • 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://www.flashandmath.com
    • 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
Adobe.swf
ce5f7936cf8e3536a88a804ce2d6902022df1794fa878bdc64a26866e34ba989		 pdf-embedded-file PDF EmbeddedFile object 16 at offset 0xAA5 55839 bytes
javascript_obj0006_000.js
44ee5c33ffec0b21b7d56f581f5bb776288d7be0676a7842b4c116f331be098a		 pdf-javascript-stream PDF /JS object 6 at offset 0xF5 1534 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s).

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