New PowerShell Backdoor Discovered

A recently detected PowerShell backdoor can steal information and execute various commands on the infected machines.

Dubbed PRB-Backdoor, the malware has been distributed via a Word document containing malicious macros. The document was named “Egyptairplus.doc” and was initially believed to deliver malware linked to the MuddyWater campaigns targeting the Middle East.

Analysis of the document’s macro revealed a function called Worker(), designed to call multiple other functions embedded in the document, to ultimately run a PowerShell command.

The command would look within the document for a chunk of embedded data that is Base64 encoded and decodes it, the security researcher behind Security 0wnage explains. This eventually results in an obfuscated PowerShell script.
 
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Link to analyis report & IOCs