I was bored so I thought I’d take a look at Ashar’s filters. I noticed he’d done a talk about it at Blackhat Europe which I was quite surprised at. Then I came across the following blog post about the talk which I pretty much agreed with. That blog post links to his filters so you can try them out yourself.

The first one is basically multiple JavaScript regexes which are far too generic to be of any value. For example “hahasrchaha” is considered a valid attack =) because it has “src” in. I’m not joking. The regexes are below.