Slash, the code that runs Slashdot and many other web sites, has a vulnerability in recent versions that allows any logged-in user to log in as any other user.
This allows users to take nearly full control of a Slash system (post and delete stories, posting stories, edit users, post as other users, etc., and do anything that a Slash user can do) by logging in to an administrator's Slash account.
Credit:
The information has been provided by Daniel Bowers.
Vulnerable systems:
Any system running Slash version 2.1.x (development versions for 2.2), 2.2.0, 2.2.1, or 2.2.2, and sites using the development code from CVS. Slash 2.0.x and previous are unaffected
Immune systems:
Slash version 2.2.3
Workaround:
In the meantime, if upgrading is not possible or will not happen immediately, site administrators should either shut down the web site or disable admin.pl and users.pl by moving them elsewhere or disabling the execution bits (Apache may need to be restarted following this).
Further, site administrators should change their passwords, and check the "seclev" field in the users table to make sure no one has a seclev greater to or equal than "100" who should not have administrator privileges:
mysql> SELECT uid, nickname, seclev FROM users WHERE seclev >= 100;
That should list only users with some administrator privileges.
Site administrators should subscribe to the slashcode-general or slashcode-announce mailing lists, to keep up to date on the latest releases and security notices. Subscription information is on the Slashcode site at http://slashcode.com/.
