‘GoldenSpy’ Malware Hidden In Chinese Tax Software

A newly identified piece of malware is being distributed embedded in tax payment software that some businesses operating in China are required to install.

Dubbed GoldenSpy, the malware was observed as part of a campaign that supposedly started in April 2020, but some of the identified samples suggest the threat has been around since at least December 2016.

One of the compromised organizations, a global technology vendor that conducts government business in the US, Australia and UK, and which recently opened offices in China, became infected after installing “Intelligent Tax,” a piece of software from the Golden Tax Department of Aisino Corporation, which a local bank required for paying local taxes.

Although it worked as advertised, the software was found to install a hidden backdoor to provide remote operators with the possibility to execute Windows commands or upload and run files.

“Basically, it was a wide-open door into the network with SYSTEM level privileges and connected to a command and control server completely separate from the tax software’s network infrastructure,” Trustwave’s Vice President of Cyber Threat Detection & Response Brian Hussey explains.

The malware was found to be digitally signed by a company called Chenkuo Network Technology, and to operate completely independent of the tax software. Thus, even if the Intelligent Tax software is uninstalled, GoldenSpy remains active on the system.

On the compromised machines, GoldenSpy is downloaded and executed two hours after the tax software has been installed. The malware was observed installing two identical versions of itself, as persistent autostart services, and uses an exeprotector module to ensure persistence.

The malware connects to its infrastructure at ningzhidata[.]com, a domain hosting other variations of GoldenSpy as well, and randomizes beacon times after the first three attempts to connect to its command and control (C&C) server.

“GoldenSpy operates with SYSTEM level privileges, making it highly dangerous and capable of executing any software on the system. This includes additional malware or Windows administrative tools to conduct reconnaissance, create new users, escalate privileges, etc.,” Trustwave notes.

What the security company could not determine was the full scope of the GoldenSpy campaign, and whether the organization was targeted because of their access to vital data, or how many other companies doing business in China have fallen victim. However, similar activity was identified at a global financial institution.

The oldest GoldenSpy samples are dated two months after Chenkuo Technology announced a partnership with Aisino in October 2016 for “big data cooperation.” However, it is uncertain whether the two organizations are willing participants in the attacks.

“GoldenSpy certainly could enable big data access and collection. Trustwave SpiderLabs has no current knowledge if GoldenSpy was active in the wild since 2016, our first identification of usage was April 2020. To be clear, we do not yet know the scope, purpose, or actors behind the threat,” Hussey says.

Hussey also recommends organizations operating in China or using the Aisino Intelligent Tax software to consider the incident as a potential threat and attempt to identify possible compromise.

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