*BSD News Article 5165


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From: tom@usblues.rt.com (Tom Markson)
Newsgroups: comp.bugs.4bsd,comp.unix.bsd
Subject: ktrace security hole in net/2?
Message-ID: <32@usblues.UUCP>
Date: 17 Sep 92 08:49:55 GMT
Organization: /dev/null, Inc
Lines: 18

When using ktrace, I found that I could trace setuid processeses even
if I don't have read permission on the binary. I am running BSDI bsd/386.

I know that in SVR4, the truss command will not allow you to trace setuid 
processes due to security implications.

Is this a security hole?  I ran su under ktrace and kdump happily dumped
out several encrypted user passwords for me.  I was not in the "wheel"
group so the su failed, but I was still able to draw out some passwords
using ktrace/kdump.

Is the solution to check if the user invoking ktrace has "read" permission
on the file before allowing a trace?  Is the SVR4 solution of disallowing
the tracing of setuid programs correct?

-- 
Tom Markson		
tom@usblues.rt.com