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Red Hat, Inc. Security Advisory
Synopsis: Denial of service attack in syslogd
Advisory ID: RHSA-1999:055-01
Issue date: 1999-11-19
Updated on: 1999-11-19
Keywords: syslogd sysklogd stream socket
Cross references: bugtraq id #809
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1. Topic:
A denial of service attack exists in the system log daemon, syslogd.
2. Relevant releases/architectures:
Red Hat Linux 4.x, all architectures
Red Hat Linux 5.x, all architectures
Red Hat Linux 6.0, all architectures
Red Hat Linux 6.1 is not vulnerable to this security issue. However,
users of Red Hat Linux 6.1/Intel may wish to upgrade to the latest
package to fix a problem in the syslog daemon where log connections
would be reset after the syslog daemon is restarted.
3. Problem description:
The syslog daemon by default used unix domain stream sockets for receiving
local log connections. By opening a large number of connections to
the log daemon, the user could make the system unresponsive.
Thanks go to Olaf Kirch (okir@monad.swb.de) for noting the vulnerability
and providing patches.
4. Solution:
For each RPM for your particular architecture, run:
rpm -Uvh <filename>
where filename is the name of the RPM.
libc updates are needed for Red Hat Linux 4.2 for the Intel and Sparc
architectures so that logging will work correctly with the upgraded sysklogd
packages.
Note: Upgrading to these sysklogd packages may impair the logging abilities
of some software that does not use the standard C library syslog(3) interface
to the system logs. Such software may have to be changed to use datagram
connections instead of stream connections to the log socket.
You can verify each package with the following command:
rpm --checksig <filename>
If you only wish to verify that each package has not been corrupted or
tampered with, examine only the md5sum with the following command:
rpm --checksig --nogpg <filename>
10. References:
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