Quoting Richard Bejtlich: “Prevention will eventually fail!”
And I have always agreed. Accidents do happen, the world is not perfect. So when companies that really spend time and money on security get breached (RSA, Lockheed, Google, [place your company here?]) then you could work out from the theory that you eventually will get breached too.
When you realize and accept that, you may need to redefine the way you think of IT security. You should prepare for the worst, so identifying what would be “the worst” for you (your company) and then identifying you most critical assets should be on the top of your list, and you should start focusing your effort on securing them the most.
Limit the users that have access to the most critical assets (and work on sensitive projects etc). The users also need special attention when it comes to awareness training and follow up. They should also have a good communication with the security staff making it easy to report anything that seems suspicious and get positive feedback no matter what. They are an important part of picking up security issues where your technology fails! So you need them.
The most critical assets needs to be monitored as close to real-time as it gets. The time it takes for an incident detection and till your response should be a minimum, even outside working hours and weekends.
Then the users who has access to theses critical systems should also have special attention/hardening on their OS’s etc. Use a modern operating system and enabling the security functionality all ready there and making sure that executables cant be executed from temporary directory etc. When you got basic security features in place (Including Anti-Virus), you should start looking at centralized logging and alerting on suspicious activities from the logs.
You should also look into implementing different ways of monitoring anomalies for the users usage. When do they normally log on? From where do they normally log on? Are they fetching lots of documents from the file servers? etc. And did they access the fake “secret document” that is there just for catching any suspicious activity? (You need to define your own anomalies).
When the inner core (most valued assets + its users) are “secured”, you should strive to maintain an acceptable level of security on the rest of the corporate office network and also importantly the public facing part. Compromises here can be used to escalate into the “inner core” or to damage your reputation and business affairs, so keeping an acceptable level of security here “as always” is good.
As “Prevention will eventually fail!”, you need to have sufficient logging up and running. So when you do have an incident, the analyst has sufficient data to work with and this will also keep the cost down, as the time it takes to handle an incident will be lower. I’m mostly into Network Security Monitoring, so for me, NetFlow type data, IDS events, full packet capture, proxy logs, and DNS queries logs are some key logs from network that will help me. On the more host side of logging, the more logging, the better… web, email, proxy, spam, anti-virus, file-access, local client logs, syslogs/eventlogs, and so on…..
And remember – if you cant spot any badness, you are not looking hard enough 🙂
I always work on the theory that something in my networks are p0wned. That keeps me on my toes and keeps me actively finding new ways to spot badness.
With that – I wish you all a hacky new year!