Messages in this thread | | | From | Jakob Lell <> | Subject | Re: hard links create local DoS vulnerability and security problems | Date | Mon, 24 Nov 2003 19:24:51 +0100 |
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On Monday 24 November 2003 19:13, Richard B. Johnson wrote: > On Mon, 24 Nov 2003 splite@purdue.edu wrote: > > On Mon, Nov 24, 2003 at 06:57:41PM +0100, Jakob Lell wrote: > > > [...] > > > Setuid-root binaries also work in a home directory. > > > You can try it by doing this test: > > > ln /bin/ping $HOME/ping > > > $HOME/ping localhost > > > [...] > > > > That's why you don't put user-writable directories on the root or /usr > > partitions. (For extra points, mount your /tmp and /var/tmp partitions > > nodev,nosuid.) Seriously guys, this is Unix Admin 101, not a major new > > security problem. > > And if the inode that was referenced in the root-owned directory > was deleted, it would no longer function as setuid root. Hello, I've just checked it out. It still works as setuid root. Just try this (as root): cp /bin/ping /tmp/ping chmod 4755 /tmp/ping su user ln /tmp/ping $HOME/ping exit rm /tmp/ping su user $HOME/ping localhost rm $HOME/ping
Regards Jakob
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