Identifying if the file begins with the standard RAR signature ( Rar! ).

Obfuscated filenames used to bypass simple signature-based filters. 2. Structural Analysis of the RAR Format

The string "UnkJ6d9xD5cU" has high Shannon entropy, suggesting it was not created by a human.

Technical Analysis of Encapsulated Data Archives: A Case Study of UnkJ6d9xD5cU.rar 1. Introduction

To safely handle an unknown archive of this nature, the following protocol is recommended: