It is the same bug as far as I know. Cheers, SkyLined ----- Original Message ----- From: "Fabian Becker" <neonomicus@xxxxxx> To: "Berend-Jan Wever" <skylined@xxxxxxxxxxxxxxx> Cc: <bugtraq@xxxxxxxxxxxxxxxxx>; <full-disclosure@xxxxxxxxxxxxxxxx> Sent: Tuesday, November 16, 2004 20:50 Subject: Re: Skype callto:// BoF technical details > Berend-Jan Wever wrote: > > >Skype reported they've found a remotely exploitable BoF in the callto:// URI handler. New version has been released. > >http://www.skype.com/products/skype/windows/changelog.html > >http://secunia.com/advisories/13191/ > > > >Technical details: > > > >The bufferoverflow happens when a skype user clicks on a "callto://username" link with a username longer then 4096 characters that does not exist: An error message is created and put into a buffer without correct size checks. The errormessage and buffer are unicode but unicode characters are filtered out and replaced with '?'. Only printable ascii characters seem to get through. A return address can be overwritten as well as the SEH. Exploitation is complicated by the fact that return addresses have to be in range 0x00??00??. > > > >Webbrowsers like MSIE do not support URI's long enough to trigger the BoF. To exploit it, one could send a skype user a callto:// link in a private message and trick him/her into clicking it. > > > >If one would want to, one could write a skype worm with this. User interaction would be required: they'd have to click the link. > > > >Cheers, > >SkyLined > > > > > > > > > > > They fixed it without knowing of the callto:// thing I suppose cause I > wrote them an email saying that the quick-call field is exploitable, > too. This was fixed within the new version. Maybe your flaw is fixed, > too, if not, I think it soon will be :) > >
