10 common network security design flaws

Brien Posey discussed 10 common network security design flaws including two that are directly related to SSL:

  1. Set it and forget it
  2. Opening more firewall ports than necessary
  3. Pulling double duty
  4. Ignoring network workstations
  5. Failing to use SSL encryption where it counts

    We all know that a Web site needs to use SSL encryption any time a user is going to be entering sensitive information, such as a username and password or a credit card number. However, many organizations make some bad decisions when it comes to securing their Web portals. The security flaw I see most often is including insecure content on a secure page. When this happens, users receive a prompt asking if they want to display both secure and insecure content. This gets users in the habit of giving Internet Explorer permission to provide insecure content. A less obvious but even more common problem is that organizations often fail to encrypt critical pages within their Web sites. In my opinion, any page that provides security information, security advice, or contact information should be SSL encrypted. It isn’t that these pages are especially sensitive. It’s just that the certificate used by the encryption process guarantees to users that they are accessing a legitimate Web page rather than a page someone has set up as a part of a phishing scam.

  6. Using self-signed certificates

    Since some organizations completely neglect the importance of SSL encryption, Microsoft has begun to include self-signed certificates with some of its products. That way, Web interfaces can be used with SSL encryption even if the organization hasn’t acquired its own certificate yet. While self-signed certificates are better than nothing, they are not a substitute for a valid SSL certificate from a trusted certificate authority. Self-signed certificates are primarily intended to help boost a product’s security until an administrator can properly secure it. Yes, a self-signed certificate can provide SSL encryption, but users will receive warning messages in their browsers because their computers do not trust the certificate (nor should they). Furthermore, some SSL-based Web services (such as ActiveSync) are not compatible with self-signed certificates because of the trust issue.

  7. Excessive security logging
  8. Randomly grouping virtual servers
  9. Placing member servers in the DMZ
  10. Depending on users to install updates

Instead of using self-signed certificates, get cheap SSL certificates to avoid error messages and potential man-in-the-middle attacks.

Originally posted on Sun Oct 25, 2009