Malicious PDF — malware analysis report

Static analysis result for SHA-256 03110abe693b9bd4…

MALICIOUS

PDF

4.5 KB Authoring application: Vabameuaki
MD5: 5acc1374d43d8cb6bfb38488814ccf0b SHA-1: 5e6d4d2f90ea36378475c4ca2d4a79177fecefe4 SHA-256: 03110abe693b9bd4faf864d0ee1738da65a831c1e671f9634e61eec2865301b2
86 Risk Score

Malware Insights

MITRE ATT&CK
T1059.007 JavaScript T1566.001 Spearphishing Attachment

The PDF contains obfuscated JavaScript, identified by heuristics as a stager. The script reconstructs strings to call `unescape` and `charCodeAt`, ultimately decoding and executing a payload. The reconstructed string `U9j%` is used in conjunction with character codes to form a URL or command, which is then executed. This indicates the document is designed to download and run a secondary malicious component.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 3

  • Page-word XOR JavaScript eval stager high PDF_PAGE_WORD_XOR_EVAL_STAGER
    PDF JavaScript enumerates rendered page words with getPageNthWord/getPageNumWords, extracts encoded byte fragments, XOR-decodes the stage with char-code helpers, and evals the result. This is an old exploit-kit staging pattern and is not normal document JavaScript.
  • 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.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0011_000.js
1ec398366107a5fedd9bcf18a57f32d68d58e87986c8ad1c876f457b209e2152
pdf-javascript-stream PDF /JS object 11 at offset 0xCA2 815 bytes