Technical Analysis by: Thomas Elkins, Natalie Zargarov
Contributions: Evan McCann, Tyler McGraw
Recently, Rapid7 observed the Fake Browser Update lure tricking users into executing malicious binaries. While analyzing the dropped binaries, Rapid7 determined a new loader is utilized in order to execute infostealers on compromised systems including StealC and Lumma.
The IDAT loader is a new, sophisticated loader that Rapid7 first spotted in July 2023. In earlier versions of the loader, it was disguised as a 7-zip installer that delivered the SecTop RAT. Rapid7 has now observed the loader used to deliver infostealers like Stealc, Lumma, and Amadey. It implements several evasion techniques including Process Doppelgänging, DLL Search Order Hijacking, and Heaven’s Gate. IDAT loader got its name as the threat actor stores the malicious payload in the IDAT chunk of PNG file format.
Prior to this technique, Rapid7 observed threat actors behind the lure utilizing malicious JavaScript files to either reach out to Command and Control (C2) servers or drop the Net Support Remote Access Trojan (RAT).
The following analysis covers the entire attack flow, which starts from a new ClearFake malware, spotted just several days ago, and ends with the stolen information in threat actors’ hands.
