RHSA-2006:0697 - Security Advisory

Topic

Updated openssh packages that fix two security flaws are now available for
Red Hat Enterprise Linux 3 and 4.

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

Description

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

Mark Dowd discovered a signal handler race condition in the OpenSSH sshd
server. A remote attacker could possibly leverage this flaw to cause a
denial of service (crash). (CVE-2006-5051) The OpenSSH project believes the
likelihood of successful exploitation leading to arbitrary code execution
appears remote. However, the Red Hat Security Response Team have not yet
been able to verify this claim due to lack of upstream vulnerability
information. We are therefore including a fix for this flaw and have rated
it important security severity in the event our continued investigation
finds this issue to be exploitable.

Tavis Ormandy of the Google Security Team discovered a denial of service
bug in the OpenSSH sshd server. A remote attacker can send a specially
crafted SSH-1 request to the server causing sshd to consume a large
quantity of CPU resources. (CVE-2006-4924)

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

Solution

Before applying this update, make sure all previously released errata
relevant to your system have been applied.

This update is available via Red Hat Network. To use Red Hat Network,
launch the Red Hat Update Agent with the following command:

up2date

This will start an interactive process that will result in the appropriate
RPMs being upgraded on your system.

Affected Products

• Red Hat Enterprise Linux Server 4 x86_64
• Red Hat Enterprise Linux Server 4 ia64
• Red Hat Enterprise Linux Server 4 i386
• 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 4 x86_64
• Red Hat Enterprise Linux Workstation 4 ia64
• Red Hat Enterprise Linux Workstation 4 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 4 x86_64
• Red Hat Enterprise Linux Desktop 4 i386
• Red Hat Enterprise Linux Desktop 3 x86_64
• Red Hat Enterprise Linux Desktop 3 i386
• Red Hat Enterprise Linux for IBM z Systems 4 s390x
• Red Hat Enterprise Linux for IBM z Systems 4 s390
• 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 4 ppc
• Red Hat Enterprise Linux for Power, big endian 3 ppc

Fixes

• BZ - 207955 - CVE-2006-4924 openssh DoS
• BZ - 208347 - CVE-2006-5051 unsafe GSSAPI signal handler

CVEs

• CVE-2006-4924
• CVE-2006-5051

References

• http://www.redhat.com/security/updates/classification/#important