Malicious PDF — malware analysis report

Static analysis result for SHA-256 73fb9d94156c3603…

MALICIOUS

PDF

2.1 KB
MD5: 8cc13c9fbff51ca84c3c1c033c3718c6 SHA-1: 81a2357b761df7cc471c590683398d78d77b41f5 SHA-256: 73fb9d94156c360334fc28cfa1ab6639f4f5d1e675734f5f200ad028dc66007c
114 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript T1204.002 Malicious Link

The PDF file contains embedded JavaScript that utilizes the `exportDataObject` and `nLaunch` functions to prompt the user to save and execute an embedded HTML file named 'HTML Javascript obfuscated.html'. This embedded file is likely a secondary payload designed to further compromise the user's system. The ML classifier strongly indicates maliciousness.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9999

Heuristics 4

  • JavaScript action low 2 related findings PDF_JAVASCRIPT
    PDF contains a /JavaScript action. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • exportDataObject + nLaunch — embedded-file launch-on-open dropper critical PDF_JS_EXPORT_LAUNCH_DROPPER
    PDF JavaScript calls exportDataObject() with nLaunch set, which extracts the document's embedded file and launches it in its default application. This is a launch-on-open dropper: the embedded file is the payload. No benign workflow auto-launches an extracted PDF attachment.
  • 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

Extracted artifacts 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
HTML_Javascript_obfuscated.html
b71ebf3c71bf7695e41f6a6a0498d651023c1dc705b6aa4b0fef1ae9bcfecf4d		 pdf-embedded-file PDF EmbeddedFile object 8 at offset 0x486 769 bytes
javascript_obj0009_000.js
c305feeddafc50535d1034d7095ce7d1bf2c2a64612e85da16d046642e471c5d		 pdf-javascript-stream PDF /JS object 9 at offset 0x616 80 bytes
Preview script
First 1,000 lines of the extracted script
this.exportDataObject({ cName: "HTML Javascript obfuscated.html", nLaunch: 2 });
javascript_obj0009_001.js
23d8b2d3162ff8b3e87bc67906f52a7615505d26a8170c4a836b96a258ea697e		 pdf-javascript-stream PDF /JS object 9 at offset 0x616 78 bytes
Preview script
First 1,000 lines of the extracted script
this.exportDataObject({ cName: "HTML Javascript obfuscated.html", nLaunch: 2 }
combined_document_js_000.js
63e624e36c5ceebfc64a3293365cf7465758a0fca1641841c1a25beef66ea145		 deobfuscated-js combined document JavaScript streams at offset 0x616 159 bytes
Preview script
First 1,000 lines of the extracted script
this.exportDataObject({ cName: "HTML Javascript obfuscated.html", nLaunch: 2 });
this.exportDataObject({ cName: "HTML Javascript obfuscated.html", nLaunch: 2 }

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