The touchdown task for May is a quick and dirty egress filtering audit. Take a look at your firewalls and make sure they are performing egress filtering (you do this, right? If not, make it happen now ~ it’s the single most effective defense against bot-nets). Once you know egress is in place, give a once over to the firewall rules that enforce it. Make sure they are effective at blocking arbitrary ports, outbound SSH, outbound VPN connections, etc. Verify that any exposed egress ports are to specific IPs or ranges. If you find any short comings, fix them.
Also take a look and make sure that violations of the firewall rules are being alerted on, so your team can investigate those alerts as potential infection sites.
Lastly, check to make sure that you have egress controls for outbound web traffic. You should be using an egress proxy for all HTTP and HTTPS traffic. Yes, you should be terminating SSL and watching that traffic for signs of infection or exfiltration of sensitive data. Take a few moments and make sure you have visibility into the web traffic of your users. If not, take that as an immediate project.
That’s it. This review should take a couple of hours or so to complete. But, the insights and security enhancements it can bring are HUGE.
Until next month, thanks for reading and run for the goal line!