Security hole in netcfg
Summary
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SuSE Security Announcement
Package: netcfg-x.x.x-x
Date: Tue Aug 25 07:10:09 MEST 1999
Affected: all Unix systems using auth daemon w/o resource control
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A security hole was discovered in the package mentioned above.
Please update as soon as possible or disable the service if you are using
this software on your SuSE Linux installation(s).
Other Linux distributions or operating systems might be affected as
well, please contact your vendor for information about this issue.
Please note, that that we provide this information on as "as-is" basis only.
There is no warranty whatsoever and no liability for any direct, indirect or
incidental damage arising from this information or the installation of
the update package.
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1. Problem Description
The way in.identd is started by inetd from a standard /etc/inetd.conf on
a SuSE Linux distribution may be exploited to mount a Denial-of-Service
attack against the system.
When inetd starts in.identd with the "wait" flag and the "-w -t120"
options, the in.identd will start to listen on the well known port
while inetd deactivates its own listener for the time in.identd
is alive.
2. Impact
If many requests (say more than a hundred or so) are sent to the
server at nearly the same time, in.identd will fork one child process
for every request. This will eventually lead to a shortage of system
resources and the computer will become unresponsive.
3. Solution
To prevent the described vulnerability, change the start flag
for in.identd in /etc/inetd.conf from "wait" to "nowait" and the
in.identd options from "-w -t120 -e" to "-i -e".
Many system administrators also decide not to run in.identd at all for
security reasons, so this may a viable alternative in its own right.
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Webpage for patches:
http://www.suse.de/patches/index.html
or try the following web pages for a list of mirrors:
http://www.suse.de/ftp.html
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References