New cyber-criminal group discovered targeting government servers, fuel, energy and aviation companies

Researchers have identified a new, previously unknown group that has systematically attacked Russia's fuel and energy complex and its aviation industry.

Additional attacks by the group, uncovered by Positive Technologies Expert Security Center (PT ESC), have targeted institutions in nine other countries, including the United States, India, Nepal, Taiwan, and Japan. In some cases, researchers discovered compromised government servers.

The group has started exploiting ProxyShell vulnerabilities in attacks aimed at infecting Microsoft Exchange, and PT ESC says it's possible vulnerable servers in the UK could be affected in the future as well. The group, known as ChamelGang, appears to be focused on stealing data from compromised networks. Its first trusted relationship attacks were registered in March 2021.

"Targeting the fuel and energy complex and aviation industry in Russia isn't unique as this sector is one of the three most frequently attacked," says Positive Technologies head of threat analysis, Denis Kuvshinov.

"However, the consequences are serious, and such attacks led to financial or data loss in 84% of all cases last year. The attacks were specifically created to steal data, and that causes major financial and reputation damage.

"Industrial companies often can't detect a targeted cyberattack on their own. They believe their defences are strong and that such disruptions are highly unlikely. But in practice, attackers can penetrate the corporate network of an industrial enterprise more than 90% of the time, and almost every such invasion leads to complete loss of control over the infrastructure.

"More than half of these attacks lead to the theft of data on company partners and employees, mail correspondence, and internal documentation," he says.

The PT ESC incident response team discovered the existence of ChamelGang while investigating security vulnerabilities in the Russian fuel, energy and aviation production sectors.

The team found that to gain access to the target enterprise's network, ChamelGang had compromised a subsidiary organisation using a vulnerable version of a web application on the open source JBoss Application Server platform. By exploiting vulnerability CVE-2017-12149 (which had been fixed by RedHat more than four years ago), the criminals could remotely execute commands on the node.

Two weeks later, which is a relatively short period, the group compromised the parent company. The attackers obtained the dictionary password of the local administrator on one of the servers in an isolated segment and penetrated the network via the Remote Desktop Protocol. The attackers remained unnoticed in the corporate network for three months, and after examining it, they gained control over most of it, including critical servers and nodes in different segments. The investigation reveals that the APT group was specifically pursuing data and succeeded in stealing it.

One distinctive feature of ChamelGang's attacks is the use of previously unknown malware, including ProxyT, BeaconLoader, and the DoorMe backdoor. The latter is a passive backdoor, which significantly complicates its detection. The group also uses better-known variants such as FRP, Cobalt Strike Beacon, and Tiny shell.

"Among the malware samples we found, the most interesting is the DoorMe backdoor," says Positive Technologies head of information security threat response, Denis Goydenko.

"This is a native IIS module that is registered as a filter through which HTTP requests and responses are processed. Its principle of operation is unusual; the backdoor processes only those requests in which the correct cookie parameter is set. At the time of the incident investigation, DoorMe was not detected by antivirus tools, and although the technique of installing this backdoor is known, we haven't seen its use in recent times."

He says the backdoor gives attackers vast opportunities in the captured systems. It can execute commands by using cmd.exe and creating a new process, write files in two ways, and copy timestamps. In total, six different commands have been implemented.

Positive Technologies have not yet linked ChamelGang to any specific country. The national CERTs have notified all the organisations affected by attacks.