A detailed analysis has uncovered the sophisticated infection chain of AsyncRAT, a potent malware strain known as an “Asynchronous Remote Access Trojan.” This malware specializes in compromising computer systems and extracting sensitive information, and what makes it particularly formidable is its stealthy behavior.
Furthermore, McAfee Labs has recently identified an ongoing AsyncRAT campaign that leverages various file types, including PowerShell, Windows Script Files (WSF), VBScript (VBS), and more, to elude antivirus detection mechanisms.
Additionally, the intricate infection chain starts with a malicious URL contained within a spam email, which triggers the download of an HTML file. This HTML file, in turn, contains an embedded ISO file, housing a WSF script. This WSF script connects to multiple URLs and executes various files in formats such as PowerShell, VBS, and BAT. These executed files serve to perform a process injection into RegSvcs.exe, a legitimate Microsoft .NET utility, allowing the attacker to conceal their activities within a trusted system application.
Following this initial stage, the PowerShell script proceeds to create a folder in the ProgramData directory and extracts files. These files are executed, leading to an intricate chain of execution involving different file types. This complexity helps evade both static and behavior-based antivirus detection. The final phase of the attack involves injecting a Portable Executable (PE) file into “C:\Windows\Microsoft.NET\Framework\v4.0.30319\RegSvcs.exe”.
Subsequently, the compromised RegSvcs.exe establishes a connection to an AsyncRAT server. The malware exhibits keylogging capabilities, records user activities, steals credentials, browser data, and crypto-related information, which is transmitted over TCP to a specific IP address and port. This multifaceted infection chain showcases the attackers‘ ability to gain remote control and successfully pilfer sensitive data while maintaining a covert presence.