XSS Infinite Loop/DoS

[vezzy]

Alright, I thought I would share this tiny logical footnote on XSS, one of the more unconventional (and arguably useless) ways to exploit it. I've posted this on boards before, so yeah.

Theoretical URL and payload:

Code: [Select]

http://example.com/index.php?s=<script>document.location=document.location</script>
It's self-explanatory, really. You tell the current document to go to itself ad nauseam, creating an infinite loop where the document is pinpointed to execute the current location constantly.

Or you have a rapid-fire automatic F5 key, the most primitive form of DoS attack. While not serving much practical purpose, I guess it could somehow be integrated as a decoy attack.

Here is a working example, courtesy of the American Nazi Party:

http://americannaziparty.com/contact.php?sendto=1-->"><script>document.location=document.location</script>

[Polyphony]

Lol, that's pretty neat.

[techb]

I seen the effect, nifty. But wouldn't this be local? If the server didn't load it from the DB or anything and your just send a req, I don't see it DDoSing anything but yourself. Not on the example page anyway.

[vezzy]

I haven't actually tested this seriously to come to a definite conclusion. I assume a slowdown would be possible, if executed on multiple machines simultaneously.

[Polyphony]

That would take A TON of people to actually DoS somebody like this, but I'm pretty sure it would work better on an "id=" database query or something, so it had to pull stuff from the DB over and over... but still it would take A TON of people doing it at the same time to make any sort of effect lol.