No longer are OS vendors and other large infrastructure technology providers the main source of vulnerabilities. It’s the thousands of applications, produced by thousands of software vendors, that make up this huge 3rd wave. ISS reported that in 2007 that the top five sources of vulnerabilities: Microsoft, Apple, Oracle, IBM, and Cisco, had dropped to supplying us with only 13.6% of our vulnerabilities. 86.4% came from the other thousands of software vendors that supply our computers with a seemingly unending supply of vulnerabilities for attackers to exploit.

In a recent report Microsoft has congratulated itself on doing a good job securing Windows. And by all accounts they have done a good job. But then they state this:

“Unless software development practices change throughout the industry, any improvements in the security of Windows would be meaningless.”

Whoa. Millions of dollars spent on securing the most prevalent piece of software and it could be meaningless? Yes, it’s true. Since attackers typically only need one vulnerability, if it isn’t in the network, and it isn’t in the host configuration, and it isn’t in the OS, they will happily exploit a vulnerability in an application.

At every shift of exploit target the problem has gotten more difficult to solve. Networks had choke points and could be centrally managed. It took a while but eventually host configurations became centrally managed and automated tools could scan configurations. Although OSes were huge and complex beasts with 10’s of millions of lines of code, with enough effort, their vulnerabilities have been largely tamed as Microsoft’s Windows and the Linux kernel track record shows. This was a very substantial, over five year effort, which used some of the most talented security people anywhere.
But now what to do? Instead of a few OSes we now have thousands of applications with vulnerabilities. As Microsoft found out, the attackers don’t go away, they just move on to the next incrementally less juicy vulnerability. In the world of exploits that typically means the vulnerability with the next smallest target population.

Attackers have started with the common client applications that can be found on almost every machine: Acrobat, Flash, RealPlayer, Quicktime, popular antivirus software. And they will continue down the popularity slope until they get to application populations down in the thousands which is getting to fairly small software vendors. Attackers can do this because they can bundle many vulnerabilities together, exploiting the statistical fact that you must have some vulnerable software installed. Compromised web sites have been found attacking visitors with over ten client side exploits preying on multiple versions of vulnerable client software.

The solution to this problem is all software must be written securely, not just the software from the big guys. Small vendors think they aren’t a target just like home users used to think they weren’t a target. People thought, “Why would someone want to attack my home computer?” Then they realized they did home banking, or had a fast internet connection that could be used for DDoS attacks or sending spam. All software vendors need to get the same wakeup call. Attackers don’t want to find a vulnerability in your software to make you look bad. They want any vulnerability. If the population of your software is small they will just bundle your vulnerability together with others in an exploit pack. The days of the average software vendor not having to worry about application security are officially over.