Bugtraq mailing list archives
Re: overwrite any file with updatedb
From: jcmurphy () SMURFLAND CIT BUFFALO EDU (Jeff Murphy)
Date: Mon, 2 Mar 1998 16:40:54 -0500
this is actually the sort command (which uses the qsort()) call that is making this files. one work around is to set the TMPDIR environment variable to a directory that only root can access. sort will then write its temporary files to that directory instead of /tmp jeff Cain <cain () TASAM COM> writes:
If this is already known, my apologies. It seemed very strange that this worked, so I thought it would be mentionable. On many linux systems(Redhat imparticularly) updatedb is run nightly around 1:00. When it sorts the files that find gets, it creats a few files in /tmp called sort0<pid>000{1,2,etc}. Each is around 512k. The first file is created and filled, then if necassary, another is created and so on until it has your whole filesystem into a nice database. Well, once the first file is created you can easily guess what the next filename will be called as only the last character will change. If you create a link to say, the shadow password file, updatedb will kindly overwrite it for you. Ex: <assuming updatedb is running in the background> $ ls /tmp sort012340000 sort012340001 $ ln -s /etc/shadow /tmp/sort012340002 <wait for awhile to give updatedb time to write to our link> $ ls /tmp sort012340000 sort012340001 sort012340002 sort012340003 It's done, it will now clear out it's files from /tmp. Now go look at the shadow password file. It will be quite larger then it was before. About 512k is it's new size. I played with this for awhile but couldn't find anyway to write anything useful to any file except /etc/shells so you can ftp into the system no matter what your specified shell is.
Current thread:
- overwrite any file with updatedb Cain (Mar 01)
- Re: overwrite any file with updatedb Kragen (Mar 02)
- Re: overwrite any file with updatedb Kragen (Mar 02)
- Re: overwrite any file with updatedb Dave G. (Mar 02)
- Re: overwrite any file with updatedb Jeff Murphy (Mar 02)
- Re: overwrite any file with updatedb Bryan Andregg (Mar 02)
- updatedb stuff Cain (Mar 02)