Malicious PDF — malware analysis report

Static analysis result for SHA-256 5058d5fe8bc04f1b…

MALICIOUS

PDF

4.5 KB Authoring application: Vabameuaki
MD5: e93c6a83fdbd49542ac3393db5e69c53 SHA-1: 954e75248bd623590149b8429c0af29593222870 SHA-256: 5058d5fe8bc04f1b85da9b7d2a1c0b0bf252ebd6b38d14ca3b701c7e5e1a5d69
86 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1566.001 Spearphishing Attachment T1204.002 Malicious File

The PDF file contains a high-confidence heuristic firing for a 'Page-word XOR JavaScript eval stager', indicating obfuscated JavaScript is used to launch further malicious activity. The embedded JavaScript stream, named 'javascript_obj0011_000.js', is the likely component responsible for this stager functionality. The primary attack pattern is therefore the execution of this embedded script, which is designed to download and execute a secondary payload. The ML classifier also strongly supports a malicious verdict.

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