A recently observed C++ version of the AZORult data stealer includes the ability to establish a remote desktop connection compromised devices, Kaspersky Lab’s security researchers have discovered.
First observed in 2016 as part of a campaign that abused PayPal for malware distribution, the threat has been used in numerous malicious attacks since.
AZORult was designed to collect various data from the infected computers and exfiltrate it to a command and control (C&C) server. It targets browser history, login credentials, cookies, files from folders as specified by the C&C, crypto-wallet files, and more.
Additionally, the threat can be used to download additional malicious programs onto the infected machines.
The C++ version of the malware was first observed in early March 2019, featuring a striking resemblance with the original, which was written in Delphi, but built by acolytes of CrydBrox, the initial AZORult author, who decided to pull the plug on it after AZORult 3.2 became too widely available.
Referred to as AZORult++ and still in development, the new malware variant first checks the language ID of the target machine and stops its execution if it identifies Russian, Armenian, Azerbaijani, Belarusian, Georgian, Kazakh, Tajik, Turkmen, or Uzbek, Kaspersky reports.
The threat does not include loader functionality and has no support for stealing saved passwords from many of the browsers. These features were apparently available in AZORult 3.3, the last known Delphi-based variant.
The two, however, feature the same algorithm for communication with the C&C server, the command format, the structure and method of storing harvested data, and encryption keys.
To remain hidden, the malware keeps the stolen data in RAM and does not write it to the hard disk. AZORult++, however, appears to be impacted by a series of issues, suggesting that the project is in the very early stages of development.
However, the security researchers expect AZORult++ to become more dangerous than its predecessor, mainly because the threat can establish a remote connection to the compromised computer.
For that, it creates a new, hidden administrator account on the machine, and sets a registry key to establish a Remote Desktop Protocol (RDP) connection, which provides attackers with complete control of the machine.
“Despite its many flaws, the C++ version is already more threatening than its predecessor due to the ability to establish a remote connection to the desktop. Because AZORult++ is likely still in development, we should expect its functionality to expand and bugs to be eliminated, not to mention attempts to distribute it widely under a name that buyers will recognize,” Kaspersky concludes.
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Ionut Arghire is an international correspondent for SecurityWeek.
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