Passwd entry

[Bob Kinne]

Thanks to the many people who responded to my request for information
about the /etc/passwd entry 

	::0:0:::

This is a large security hole, allowing anyone on the machine to
become root.  In BSD 4.2 (at least), a blank line or corrupted
entry in the /etc/passwd file can be changed to such an entry by
such programs as passwd, yppasswd, chsh, chfn.  This problem exists
in ULTRIX 3.0, which we run.  I don't know if it has been corrected
in 3.1, or what other flavors of UNIX it exists in.

My main concern was to find out how this entry could have gotten
into a /etc/passwd file.  Since this was apparently due to a security
hole in ULTRIX, I do not suspect any deliberate attempt to attack
the system.  Thanks for your help.

Bob Kinne	 	Optoelectronics Computing Center    
UCB, Campus Box 525	VOICE		(303) 492-3330
Boulder, CO 80309	INTERNET	bobk at boulder.Colorado.EDU