Trustwave’s security researchers have identified a total of five uninstallers meant to remove the GoldenSpy backdoor from infected computers.
The GoldenSpy malware was initially detailed in late June, and was likely deployed since April 2020, via an official tax application that foreign companies doing business in China are required to install. The financial software worked as expected, but it also installed a hidden backdoor.
Called GoldenSpy, the backdoor was later found to have been preceded by GoldenHelper, another malware family silently installed via official Chinese tax software. In late June, the FBI issued an alert to warn healthcare, chemical, and finance organizations in the United States of the threat.
In late June, soon after the initial report on GoldenSpy was published, the actors behind it leveraged the update mechanism within the tax software to deliver an uninstaller to the infected machines and completely remove the malware and additional artifacts, including the uninstaller.
Today, Trustwave revealed that a total of five GoldenSpy uninstallers have been released to date, some of which have been uploaded to public repositories, thus increasing their detection rates.
“Understanding the attackers were watching our every move to help organizations impacted by GoldenSpy, we waited a period-of-time and quietly kept tracking with our threat hunting strategy. What we found is that they are continuing to push new GoldenSpy uninstallers – so far we have discovered five variants totaling 24 uninstaller files,” Trustwave says.
All of the identified uninstaller variants show identical behavior, although some of them use different execution flows and string obfuscation. The size of the uninstallers also differs, helping them evade detection.
Analysis of the uninstallers allowed the security researchers discover that, starting with the third variant, subsequent samples would send a unique ID to the domain ningzhidata[.]com, allowing the adversary to track the code’s activity.
The investigation also revealed that the code would use the IP 39[.]98[.]110[.]234 for a third stage beacon, and the security researchers linked the address to Ningbo Digital Technology Co., Ltd, a company that claims to provide technical support for professional companies and technology service providers.
On their website, the company provides two files for download, which Trustwave identified as being a GoldenSpy dropper (called iclient) and the GoldenSpy uninstaller (named QdfTools). Ningbo Digital Technology says it’s offering the uninstaller as “Enterprise service environment detection and cleaning software.”
“Based on these findings, we can say that Ningbo Digital Technology Co., Ltd is involved with the development of the ‘GoldenSpy Uninstaller’ and ningzhidata[.]com serving from CDN servers,” Trustwave concludes.