On October 2, 2019, the UK’s National Cyber Security Centre (NCSC) released a notice stating that Pulse Secure, Palo Alto, and Fortinet’s SSL VPN solutions are vulnerable. These vulnerabilities consist of retrieving arbitrary files, some including authentication credentials, as well as post-auth command injection. Unauthorized access into any network is a huge alarm and could allow second-stage attacks.
It is advised that customers investigate their logs for indicators of compromise, especially if the software wasn’t patched right away. Things to look for in the logs are unknown IP address and odd connection times. If users work from home, verifying their IP address is a start, but administrators should also look at all the IPs used to initiate connections. Of course, be sure to have all users change their passwords to error on the side of caution!
The NCSC’s post provided some data to look for in any available logs, granted logging was enabled and stored. For Pulse Connect Secure, NCSC suggests looking for logs containing “/dana/html5acc/guacamole/”. Fortigate doesn’t log web requests by default (which is a big deal when it comes to analysis; make sure to log relevant events!) but if administrators enabled logging, searching for file downloads of about 200 KB or so is suggested. The file is the sslvpn_websession file which contains active users’ usernames and passwords. As for Palo Alto, log detections have proven difficult, but it is suggested to look for any crash logs, which could be a sign of failed exploits.
Summary of Key Takeaways
Make sure logging is enabled and stored for a sufficient amount of time, should there be a need for analysis. There is no single answer for how long to store logs for, but 90 days is a start. Remember, compromises aren’t noticed right away. In fact, some organizations may never realize this! Some have taken more than 100 days to become aware. If you have a dedicated log analyst, then the detection rate may be faster. Proper training is key here as well as investigative work.
WatchGuard’s SSL VPN solution allows incorporation of AuthPoint, a multi-factor authentication (MFA) solution. Consider enabling MFA for any and all corporate logins, as lost passwords are useless without approval from the MFA solution. That said, get an MFA solution!
Lastly, after further investigation, make sure to wipe devices if needed. It’s better to wipe and restore from backups than continue on uncertain of the extent of the damages incurred. You are backing up, right?