RHSA-2005:550 - Security Advisory

Topic

Updated openssh packages that fix a potential security vulnerability and
various other bugs are now available.

This update has been rated as having low security impact by the Red Hat
Security Response Team.

Description

OpenSSH is OpenBSD's SSH (Secure SHell) protocol implementation. This
includes the core files necessary for both the OpenSSH client and server.

A bug was found in the way the OpenSSH server handled the MaxStartups and
LoginGraceTime configuration variables. A malicious user could connect to
the SSH daemon in such a way that it would prevent additional logins from
occuring until the malicious connections are closed. The Common
Vulnerabilities and Exposures project (cve.mitre.org) has assigned the name
CAN-2004-2069 to this issue.

Additionally, the following issues are resolved with this update:

• The -q option of the ssh client did not suppress the banner message sent

by the server, which caused errors when used in scripts.

• The sshd daemon failed to close the client connection if multiple X

clients were forwarded over the connection and the client session exited.

• The sftp client leaked memory if used for extended periods.
• The sshd daemon called the PAM functions incorrectly if the user was

unknown on the system.

All users of openssh should upgrade to these updated packages, which
contain backported patches and resolve these issues.

Solution

Before applying this update, make sure that all previously-released
errata relevant to your system have been applied. Use Red Hat
Network to download and update your packages. To launch the Red Hat
Update Agent, use the following command:

up2date

For information on how to install packages manually, refer to the
following Web page for the System Administration or Customization
guide specific to your system:

http://www.redhat.com/docs/manuals/enterprise/

Affected Products

• Red Hat Enterprise Linux Server 3 x86_64
• Red Hat Enterprise Linux Server 3 ia64
• Red Hat Enterprise Linux Server 3 i386
• Red Hat Enterprise Linux Workstation 3 x86_64
• Red Hat Enterprise Linux Workstation 3 ia64
• Red Hat Enterprise Linux Workstation 3 i386
• Red Hat Enterprise Linux Desktop 3 x86_64
• Red Hat Enterprise Linux Desktop 3 i386
• Red Hat Enterprise Linux for IBM z Systems 3 s390x
• Red Hat Enterprise Linux for IBM z Systems 3 s390
• Red Hat Enterprise Linux for Power, big endian 3 ppc

Fixes

• BZ - 129289 - [PATCH] SSH -q flag does not suppress banner text
• BZ - 151080 - sftp over a persistent connection (days/weeks) develops a memory leak.
• BZ - 156996 - CAN-2004-2069 openssh DoS issue

CVEs

• CVE-2004-2069

References

(none)