When is a Vulnerability not a Vulnerability?

Until this week, I had thought this question would be answered by checking the vulnerability could be exploited and by determining whether there was any technical or business impact.

But I have just finished reading the Summer 2010 edition of Information Security Now, the quarterly magazine of the BCS Security Forum, incorporating the Information Security Specialist Group. One of the articles forced me to stop and think.

The article titled "Attack Spotting" describes the motivation for modern attackers and in particular attacks on application software. But the author introduces the idea of "non-vulnerability attacks". Just what might they be?

I was even more confused. I thought a vulnerability was any weakness that could be exploited by a threat (and a similar definition). The article's author goes on to describe that in "traditional vulnerability-based attacks", there is always the possibility of creating a signature to block the attack or of developing a patch for the application. In "non-vulnerability-based attacks" the author says there is no malicious payload and therefore it is not possible to create an attack signature or patch. The author helpfully provides three examples of non-vulnerability attacks:

• Brute force attack on authentication
• Web application vulnerability scanning
• Service flooding which exhaust server resources

No, no, no! These are all attacks against real vulnerabilities. These three are listed in Common Weakness Enumeration (CWE) (e.g. CWE-307, CWE-200 and CWE-410) and real examples are listed in Common Vulnerabilities and Exposures (CVE). The examples also fall into categories in the Web Application Security Consortium 's Threat Classification.

I have to disagree that these attack methods are new, and that they are not being detected. I may have misunderstood the article, but I believe there is plenty of guidance on building applications securely, security verification and for testing for these types of flaws. I also disagree with the article author's suggestion that the answer lies with expert systems to perform network behavioural analysis (NBA). Why bother? The application already knows right from wrong and doesn't need to guess. Implement application-based intrusion detection and prevention, on top of secure code, and benefit from very low false positives. At least, that's my view.

So, perhaps if it depends on your viewpoint. Maybe some traditional security folk see this other stuff as black magic? I hope not.