DoS and Root Compromise Kernel Bug?

Jeremy Andrews (jeremy@kerneltrap.com)
Fri, 19 Oct 2001 14:08:53 -0400


Hello,

Yesterday Rafal Wojtczuk posted to BugTraq regarding two kernel bugs:

http://www.securityfocus.com/cgi-bin/archive.pl?id=1&mid=221337&start=2001-10-15&end=2001-10-21

I'm curious to understand more about these bugs. I.E., are they real? And,
are they fixed in 2.4.12 as claimed? How about in the -ac series?

The first kernel bug is regarding symbolic links. Rafal says it is partially
fixed in 2.4.10, and completely fixed in 2.4.12. This bug allows for a local
user to carry out a Denial of Service attack.

The second bug allows for a root compromise via ptrace. The requirements are
that /usr/bin/newgrp be suid root (as in my RedHat 7.0 server), and that newgrp
not prompt for a password when run without arguments (again, as is the case with
my RedHat 7.0 server). Rafal says the attack only appears to work on Linux.

Thanks,
-Jeremy

--
 Jeremy Andrews    <mailto:jeremy@kerneltrap.com>
 PGP Key ID: 8F8B617A  http://www.kerneltrap.com/
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