Friday, May 6, 2022

The Cylance Smart Antivirus agent will ruin your day

I am currently helping a customer move their ITM 6 infrastructure from AIX to Red Hat 8, and the largest hurdle has been the Cylance agent. When doing any kind of enterprise install, my first step is to copy the install files to all of the servers (in this case it is 16 servers: 2 HUB TEMS, 12 RTEMS, 2 TEPS). In its default configuration, the Cylance agent will remove files that it determines are suspicious. In my case, that means that it deleted one or two tar files, and would re-delete them whenever I copied them over again. The cylance log under /opt/cylance/desktop/log showed exactly what it was doing, so we were able to work with the Cylance team to correct this.

After the delete issue was resolved, we found that the Cylance agent was stopping some executables from running, with just a "Segmentation fault" error, and the error still existed after stopping the Cylance agent. This is because even though the agent wasn't running, it has hooks into kernel system calls that leverage a local cache. That took a while to resolve, but we finally got all of the appropriate directories whitelisted.

The last problem encountered was with the Cylance agent's Memory Protection feature. In this case, it caused 'tacmd tepslogin' to fail with a bunch of text to the command line and no information in the normal ITM logs. Looking in the Cylance log file again, I could see that it was blocking some memory action performed by the ITM java executable. That now seems to be resolved.

Hopefully this short post can help others identify these types of issues before throwing their server out the window.