Additional Targets Include the United States, India, Nepal, Taiwan, and Japan, Where Government Servers Have Been Compromised in Some Cases

Researchers at the Positive Technologies Expert Security Center (PT ESC) have identified a new, previously unknown APT group that has systematically attacked mainly the fuel and energy complex and aviation industry in Russia. Additional attacks uncovered by PT ESC have targeted institutions in 9 other countries, including the United States, India, Nepal, Taiwan, and Japan, where in some cases, researchers discovered compromised government servers. Since the group has started exploiting ProxyShell vulnerabilities in attacks to infect Microsoft Exchange, it’s possible that vulnerable servers in the UK could be affected in the future as well. The group, known as ChamelGang, appear to be focused on stealing data from compromised networks, and its first trusted relationship attacks ¹ were registered in March 2021.

Denis Kuvshinov, Head of Threat Analysis at Positive Technologies, explains: "Targeting the fuel and energy complex and aviation industry in Russia isn’t unique—this sector is one of the three most frequently attacked. However, the consequences are serious: Most often such attacks lead 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 reputational damage. Also, industrial companies often can’t detect a targeted cyberattack on their own—they believe their defenses are b, 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."

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 organization 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 were able to remotely execute commands on the node. Two weeks later, which in this dynamic represents a relatively short time period, the group was able to compromise 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 (RDP). ² The attackers remained unnoticed in the corporate network for three months; 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.

In the second case revealed by PT ESC, the attackers exploited a chain of related vulnerabilities in Microsoft Exchange (CVE-2021-34473, CVE-2021-34523, CVE-2021-31207) called ProxyShell. This became public last month, and ever since it has been actively exploited by other APT groups. The attackers gained access to the company's mail servers using a backdoor that had not been detected by most antivirus tools at the time of the attack. As in the first case, the criminals were after sensitive data, but the detection of the APT group and active countermeasures prevented serious theft. The attackers were inside the target organization's infrastructure for only eight days, and didn’t have the time to cause much harm.

One distinctive feature of ChamelGang's attacks is the use of new malware: ProxyT, BeaconLoader, and the DoorMe backdoor, which were not previously known. 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.

Denis Goydenko, Head of Information Security Threat Response at Positive Technologies, says: "Among the malware samples we found, the most interesting is the DoorMe backdoor. 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. The backdoor gives attackers wide 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."

The group was named ChamelGang (from chameleon) for using plausible phishing domains and features of operating systems to mask malware and network infrastructure. For example, attackers register phishing domains that imitate legitimate services of large international companies, such as Microsoft, TrendMicro, McAfee, IBM and Google, including their support services, content delivery, and updates. While studying the group's activity, PT ESC specialists found domains newtrendmicro.com, centralgoogle.com, microsoft-support.net, cdn-chrome.com, and mcafee-upgrade.com. The APT group also placed SSL certificates on its servers that imitated legitimate ones (github.com, ibm.com, jquery.com, and update.microsoft-support.net).

Positive Technologies experts have not yet linked ChamelGang to any specific country. All the organizations affected by attacks have been notified by the national CERTs.

A detailed report about ChamelGang, its tactics and the new malware discovered is available here: https://www.ptsecurity.com/ww-en/analytics/pt-esc-threat-intelligence/new-apt-group-chamelgang/

1. A trusted relationship attack is an attack in which criminals hack the infrastructure of a third-party company whose employees have legitimate access to the victim's resources. For example, subsidiaries may become the first link in the chain of attacks on the parent organization; in other cases, the attack may begin with hacking the company providing technical support. Such attacks are associated with the compromise of trusted channels (VPN, for example); however, they are often confused with supply chain attacks, which are carried out using software and hardware means: an implant is embedded in the tool itself or in one part of the update to provide direct access to the server or establish a connection with the C2.
2. The Remote Desktop Protocol is a protocol for connecting a user to a remote desktop via a terminal server.