[OpenBSD]
For 2.1 security advisories, please refer here.
For 2.2 security advisories, please refer here.
For 2.3 security advisories, please refer here.
For 2.4 security advisories, please refer here.
For 2.5 security advisories, please refer here.

OpenBSD Security Views

OpenBSD believes in strong security. Our aspiration is to be NUMBER ONE in the industry for security (if we are not already there). Our open software development model permits us to take a more uncompromising view towards increased security than Sun, SGI, IBM, HP, or other vendors are able to. We can make changes the vendors would not make. Also, since OpenBSD is exported with cryptography, we are able to take cryptographic approaches towards fixing security problems.

Like many readers of the BUGTRAQ mailing list, we believe in full disclosure of security problems. Security information moves very fast in cracker circles. On the other hand, our experience is that coding and releasing of proper security fixes typically requires about an hour of work -- very fast fix turnaround is possible. Thus we think that full disclosure helps the people who really care about security.

Our security auditing team typically has between six and twelve members who continue to search for and fix new security holes. We have been auditing since the summer of 1996. The process we follow to increase security is simply a comprehensive file-by-file analysis of every critical software component. Flaws have been found in just about every area of the system. Entire new classes of security problems have been found during our audit, and often source code which had been audited earlier needs re-auditing with these new flaws in mind. Code often gets audited multiple times, and by multiple people with different auditing skills.

Some members of our security auditing team worked for Secure Networks, the company that made the industry's premier network security scanning software package Ballista (Secure Networks got purchased by Network Associates, Ballista got renamed to Cybercop Scanner, and well...) That company did a lot of security research, and thus fit in well with the OpenBSD stance. OpenBSD passes Ballista's tests with flying colours.

Another facet of our security auditing process is its proactiveness. In most cases we have found that the determination of exploitability is not an issue. During our ongoing auditing process we find many bugs, and endeavor to fix them even though exploitability is not proven. We fix the bug, and we move on to find other bugs to fix. We have fixed many simple and obvious careless programming errors in code and only months later discovered that the problems were in fact exploitable. (Or, more likely someone on BUGTRAQ would report that other operating systems were vulnerable to a `newly discovered problem', and then it would be discovered that OpenBSD had been fixed in a previous release). In other cases we have been saved from full exploitability of complex step-by-step attacks because we had fixed one of the intermediate steps. An example of where we managed such a success is the lpd advisory that Secure Networks put out.

Our proactive auditing process has really paid off. Statements like ``This problem was fixed in OpenBSD about 6 months ago'' have become commonplace in security forums like BUGTRAQ.

The most intense part of our security auditing happened immediately before the OpenBSD 2.0 release and during the 2.0->2.1 transition, over the last third of 1996 and first half of 1997. Thousands (yes, thousands) of security issues were fixed rapidly over this year-long period; bugs like the standard buffer overflows, protocol implementation weaknesses, information gathering, and filesystem races. Hence most of the security problems that we encountered were fixed before our 2.1 release, and then a far smaller number needed fixing for our 2.2 release. We do not find as many problems anymore, it is simply a case of diminishing returns. Recently the security problems we find and fix tend to be significantly more obscure or complicated. Still we will persist for a number of reasons:

The auditing process is not over yet, and as you can see we continue to find and fix new security flaws.

OpenBSD 2.5 Security Advisories

These are the OpenBSD 2.5 advisories -- all these problems are solved in OpenBSD current. Obviously, all the OpenBSD 2.4 advisories listed below are fixed in OpenBSD 2.5.