About nixCraft

Topics

Security Alert: Debian OpenSSH packages Fix Denial of Service

Posted by Vivek Gite [Last updated: September 16, 2008]

Debian Linux project released the OpenSSH security updates for computers powered by its Debian Linux operating systems. The Openssh package has remote unsafe signal handler DoS Vulnerability. It has been discovered that the signal handler implementing the login timeout in Debian's version of the OpenSSH server uses functions which are not async-signal-safe, leading to a denial of service vulnerability.

Systems affected by this issue suffer from lots of zombie sshd processes. Processes stuck with a "[net]" process title have also been observed. Over time, a sufficient number of processes may accumulate such that further login attempts are impossible. Presence of these processes does not indicate active exploitation of this vulnerability.

Package        : openssh
Vulnerability  : remote
Problem type   : unsafe signal handler
Debian-specific: no
CVE Id(s)      : CVE-2008-4109
Debian Bug     : 498678

How do I fix this problem?

Login as root and type the following commands to update the internal database, followed by corrected packages installation:
# apt-get update
# apt-get upgrade

E-mail this to a Friend    Printable Version

Linux Powered Asus EEE Laptop PC From $299

You may also be interested in other helpful articles:

Discussion on This Article:

  1. Didier Says:

    Thanks for this news. I don’t see it before.
    It’s true that on some servers, I don’t check every days for update.

    ;-)

Leave a Reply

We encourage your comments, and suggestions. But please stay on topic, be polite, and avoid spam. Thank you very much for stopping by our site!

XHTML: You can use these tags: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>

*
To prove you're a person (not a spam script), type the security word shown in the picture. Click on the picture to hear an audio file of the word.
Click to hear an audio file of the anti-spam word

Tags: , , , , , , , , , , ,

Copyright © 2004-2008 nixCraft. All rights reserved - TOS/Disclaimer - Privacy policy - Sitemap - Powered by Open source software.