I know you may think that this is useless, since if you boot off the cd or disk, you already have better access to the machine, however doing this method gets you admin access WITHOUT changing the password, correct?
Again, perhaps I'm misunderstanding, but wouldn't this work, and still show that the vulnerability in the screensaver code is valid, and needs to be updated? It could allow someone to get local admin access to the machine without changing the password.
3APA3A wrote:
Dear Matthew Walker,
Permissions for HKEY_USERS\Control Panel\Desktop allow modification to only members of Administrators and System.
Power Users can install software, so they can replace any file in SYSTEM32 directory, including screensaver. It allows to trojan any system file (for example, one can replace winspool.exe with cmd.exe to obtain SYSTEM permissions). It's by design and it's documented. Just never assign users in Power Users group, as Microsoft recommends you. I see no security vulnerability here.
--Wednesday, November 24, 2004, 8:36:14 PM, you wrote to [EMAIL PROTECTED]:
MW> To Whom it May Concern; MW> The Original Post is http://www.securityfocus.com/bid/11711
MW> On Windows XP all releases, when you replace, or change the MW> screensaver displayed on the login screen with a specially crafted MW> version designed to execute programs, those programs are launched MW> under the SYSTEM SID, IE: they are given automatically the highest MW> access level avalible to Windows. This level is not accessible even MW> to administrators.
MW> This flaw is important because while one would need Power User MW> privledges or above to change the Login Screensaver, by default, any MW> user with the exception of guest can replace the login screensaver MW> file with a modified version. In theory, any determined user could MW> execute ANYTHING with SYSTEM privledges. A similar flaw exists in MW> Win2K, but Microsoft has ignored it.
MW> Sincerly; MW> Matt Walker
MW> _______________________________________________ MW> Full-Disclosure - We believe in it. MW> Charter: http://lists.netsys.com/full-disclosure-charter.html
_______________________________________________ Full-Disclosure - We believe in it. Charter: http://lists.netsys.com/full-disclosure-charter.html
