An intel source recently provided Cisco Talos with modified versions of the TeamTNT cybercrime team's infected shell scripts, an earlier version of which was documented by Trend Micro. The malware creator modified these tools after learning that security experts had disclosed the prior version of its scripts. These scripts are intended primarily for Amazon Web Services (AWS), but they might also be used on-premise, in containers, or in other Linux instances.
There are multiple TeamTNT payloads focusing on bitcoin mining, persistence, and lateral movement employing tactics like identifying and installing on with all Kubernetes pods in a local network, in addition to the primary credential stealer scripts. A script containing user credentials for the distribution system server and another with an API key which may allow remote access to a tmate shared login session is also included. Defense evasion functions aimed at defeating Alibaba cloud security technologies are included in some TeamTNT scripts.
When it comes to decision making obtaining credentials, the script looks for them in the following places and APIs:
- It attempts to obtain the string 'AWS' from /proc/*/environ from the Linux system environment variables.
- Obtaining the string 'AWS' from Docker environment variables with the command $(docker inspect $) (docker ps -q).
- /home/.aws/credentials and /root/.aws/credentials are the default AWS CLI credential file locations.
While the query itself will not be caught by Cisco Secure Cloud Analytics, the alert "AWS Temporary Token Persistence" will detect later use of these credentials to generate further temporary credentials. Finally, the virus saves any credentials acquired by the preceding functions to the file "/var/tmp/TeamTNT AWS STEALER.txt" and uses cURL to transfer it to the URL http://chimaera[.]cc/in/AWS.php before deleting it.
No CloudTrail, GuardDuty, or SCA events were generated when the script ran on the target EC2 instance for all network traffic was restricted by the VPC Security Group such as the script could not access TeamTNT's servers.
The core of the defense impairment functions is directed against Alibaba Cloud Security's numerous agents, how, they also target Tencent Cloud Monitor and third-party BMC Helix Cloud Security, agents. While the bulk of malicious scripts targets AWS Elastic Compute Cloud (EC2) virtual machines, these bots are most typically detected running inside Alibaba Cloud Elastic Compute Service (ECS) or a Tencent Cloud VM. They could theoretically be put on a VM operating on AWS or any other service, but it would be unusual. TeamTNT makes no attempt to disable AWS CloudWatch, Microsoft Defender, Google Cloud Monitor, Cisco Secure Cloud Analytics, CrowdStrike Falcon, Palo Alto Prisma Cloud, or other popular cloud security tools in the United States.
The Alibaba defense damage routines have been retrieved and saved here from the script Kubernetes root payload 2.sh. Since static analysis of the defense impairment functions is problematic due to the presence of multiple Base64 encoded strings, those functions have been decrypted and placed back into the file ali-defense-impairment-base64-decoded.sh.txt.
"Cybercriminals who have been exposed by security researchers should update those tools to keep functioning successfully," stated Darin Smith of Talos.
The serious remote code execution problem in Spring Framework (CVE-2022-22965) has been leveraged to deploy cryptocurrency miners, in yet another example of how threat actors quickly co-opt recently revealed flaws into existing attacks. To deploy the cryptocurrency miners, the exploitation efforts employ a unique web shell, but not before switching off the firewall and disabling other virtual currency miner processes.
