Russia-Linked Sandworm Group Replaces VPNFilter With New Malware
Following the 2018 public exposure of the VPNFilter malware, the Russia-linked Sandworm threat group has developed a replacement malware framework, which has mainly targeted firewall appliances, government agencies in the United States and the United Kingdom warn.
Also referred to as APT28, Fancy Bear, Sednit, Sofacy, and Voodoo Bear, the Sandworm hacking group is believed to be part of the Main Intelligence Directorate of the General Staff of the Armed Forces of the Russian Federation (GRU).
Historically, Sandworm has engaged in numerous cyberattacks targeting Ukraine, such as the 2015 BlackEnergy and the 2016 Industroyer attacks, as well as incidents with a broader impact, such as the 2017 NotPetya operation, and the 2018 attacks on the Winter Olympics and Paralympics.
In 2018, the United States announced that it had disrupted the “VPNFilter” botnet, but shortly after, the Security Service of Ukraine (SBU) said the Aulska chlorine station in Auly, Dnipropetrovsk, was targeted with the VPNFilter malware, likely in an attempt to disrupt operations at the critical infrastructure plant.
[READ: Hundreds of Networks Still Host Devices Infected With VPNFilter Malware]
In January last year, Trend Micro discovered that hundreds of networks worldwide still contained devices vulnerable to VPNFilter, such as network-attached storage (NAS) devices and small office/home office (SOHO) routers. Thousands of products were likely still infected.
In a joint advisory on Wednesday, the United Kingdom’s National Cyber Security Centre (NCSC) and the U.S. Cybersecurity and Infrastructure Security Agency (CISA), the National Security Agency (NSA) and the Federal Bureau of Investigation (FBI) revealed that Sandworm has replaced VPNFilter with a new malware framework, called Cyclops Blink.
Likely active since 2019, Cyclops Blink has been used in attacks without discrimination, mainly deployed on WatchGuard firewall appliances. The observed samples were developed for PowerPC (big-endian) architecture, but the four agencies believe that Sandworm is capable of compiling the malware for other architectures and firmware as well.
“The malware itself is sophisticated and modular with basic core functionality to beacon device information back to a server and enable files to be downloaded and executed. There is also functionality to add new modules while the malware is running, which allows Sandworm to implement additional capability as required,” the joint advisory reads.
[READ: More Russian Attacks Against Ukraine Come to Light]
Cyclops Blink is typically deployed post exploitation as part of a firmware ‘update’ and achieves persistence at device reboot, which makes remediation more difficult. Delivered as a malicious Linux ELF executable and featuring a modular design, the malware’s capabilities can be expanded while it is running.
Cyclops Blink is loaded into memory as two program segments, one with read/execute permissions and another with read/write permissions. The first contains the Linux ELF header and executable code, while the second contains the data used by the malware, NCSC explains in a separate technical report.
The malware’s modular framework consists of a core component and modules that run as child processes. Several modules – responsible for file downloads/uploads, device information gathering, and malware updates – are built-in and executed at launch.
According to NCSC, Cyclops Blink’s developers likely reverse-engineered the WatchGuard Firebox firmware update process to identify vulnerabilities in the process and exploit them. WatchGuard has worked closely with the FBI, CISA and the NCSC to deliver the resources necessary for removing the malware from infected devices.
WatchGuard estimates that roughly 1% of active firewall appliances – which are mainly used by business customers – are impacted.
“Only those appliances that had been configured to have management open to the Internet are vulnerable to Cyclops Blink,” the company said. “Firewall appliances are not at risk if they were never configured to allow unrestricted management access from the Internet. Restricted management access is the default setting for all WatchGuard’s physical firewall appliances. No other WatchGuard products are impacted.”
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