In loom of recent internet attacks many institutions have started scrambling in attempt to "strengthen" their security stance. I agree that auditing our systems and networks for potential flaws seems appropriate at this time to prevent getting "caught with our pants down". Incidentally, I have recently witnessed the introduction of silly and at times ineffective security adjustments. Many of these new procedures, rules, and requirements do not make us more secure and worse instill a false sense of security.
I have previously addressed the fallacy of absolute security. No system is perfect. A successful security model accomplishes fortitude by implementing layers like an onion. Through the use of security layers we can significantly hamper attack vectors and create a safer complex.
When analyzing a potential attack vector we must first determine our current location in the security layers. This step serves two purposes:
- to prevent wasting time and energy on vulnerabilities that don't matter at that point in our matrix.
- to prevent causing outages and unneeded administrator and customer heartache.
If a vulnerability requires root or elevated privileges to occur, don't waste your time resolving it. If the attacker already has root, you have bigger problems on your hands.
Some real life examples:
- Firewall denying a large range of IP addresses (like entire countries). This truly does not increase security, it just creates headaches for users. An attacker could just proxy to an open range (like a VPS based in a more trusted zone) and gain access from there. Also if you decide to ignore this advice and create blanket IP range deny rules, DON'T also block services intended to be internet-facing. For example, don't block your Internet-facing DNS server if it is authoritative for public domains. This will cause countless intermittent issues and will be a nightmare to diagnose.
- Weekly Scanning for Windows viruses on network shares or data at rest. This hammers the servers for no reason. If all the desktops run antivirus then the file was already scanned when it was downloaded. That same file will be scanned again when retrieved on the share. If you want the warm and fuzzys of virus scanning network file shares, do it once a year. These scans waste time and resources. I feel even more outraged when asked to virus scan network shares hosted on UNIX servers or NAS.
I speculate that most of these arbitrary ideas come about because the people in charge make uninformed decisions out of fear without first consulting the appropriate subject matter experts.
Unfortunately, once a security mandate occurs it seems difficult to expunge. People are just not willing to put their neck on the chopping block to banish a legacy or silly mandates; So we end up living with nonsensical rules and procedures.