F5 researcher Liron Segal said the currency being mined was monero and the attackers were targeting Linux systems.
The campaign has been called CroniX by F5 as it uses cron to remain persistent and Xhide for launching executables with fake process names,
As iTWire reported on 26 August, the security firm Recorded Future claimed to have found proof-of-concept code on GitHub for exploiting the same flaw.
Segal said the exploit developed by the CroniX attackers injected Object-Graph Navigation Language expressions, which might contain malicious Java code, with the injection point being inside the URL.
"The attacker sends a single HTTP request while injecting an OGNL expression that, once evaluated, executes shell commands to download and execute a malicious file," Segal wrote.
Three cron jobs were set in place so the mining script could achieve persistence and any other processes on the infected machine put in place by any other cryptocurrency miner were killed.
"For some miners, the attacker decides to take a more careful approach and check each process name and process CPU usage and then kill only those processes that utilise 60% or more of the CPU resources," Segal said.
"This is probably done to avoid killing legitimate processes as the names of these miners (crond, sshd and syslogs) typically relate to legitimate programs on a Linux system."
He said the way in which the CroniX malware was deployed resembled the way a flaw in Jenkins servers had been exploited two months ago. While the Jenkins exploit had been hosted on a Chinese Git website, this time a Web server hosted in the US was being used along with a Palau domain name registered by someone with a Russian name.
Segal commented: "Considering it’s only been two weeks since this vulnerability was discovered, it’s worth noting how fast attackers are weaponising vulnerabilities and how quickly researchers are seeing them in the wild."