Hackers are exploiting vulnerable Jira and Exim servers with the end goal of infecting them with a new Watchbog Linux Trojan variant and using the resulting botnet as part of a Monero crypto mining operation.
Watchbog is a malware strain used to infect Linux servers by exploiting vulnerable software such as Jenkins during a campaign from May, as well as Nexus Repository Manager 3, ThinkPHP, and Linux Supervisord as part of the operation from March as discovered by Alibaba Cloud Security researchers.
The newest variant spotted by Intezer Labs’ researcher polarply on VirusTotal uses a malicious payload designed to exploit the 12-day old Jira template injection vulnerability tracked as CVE-2019-11581 that leads to remote code execution.
It will also abuse the Exim remote command execution flaw tracked as CVE-2019-10149 which enables attackers to execute commands as root following exploitation — this Exim flaw is known to have been exploited in the wild since at least June 9.
As per a Shodan search from today, there are more than 1,610,000 unpatched Exim servers that could be affected by this attack, as well as over 54,000 vulnerable Atlassian JIRA servers as per BinaryEdge.
What makes it highly dangerous is that this variant is not detected by any of the scanning engines on VirusTotal seeing that the Watchbog sample spotted by polarply has an AV detection ratio of 0/55 — more info is available on Intezer Analyze.
Watchbog’s infection process is quite straightforward as it drops a Monero coin miner after exploiting the vulnerabilities it targets and it gains persistence to fend off the users’ attempts of removing it.
After getting a foothold on the vulnerable servers, Watchbog will download and execute malicious commands from pastebin that will eventually deploy and launch the final cryptocurrency miner payload on the compromised Linux boxes.
The malware will also achieve persistence by adding itself to multiple crontab files to make sure that it can come back and reinfect the system if the user will not find all of the altered crontabs.
Submitted by: Arnfried Walbrecht