Updated openssh packages that fix two security flaws are now available for CentOS Linux 3 and 4. This update has been rated as having important security impact by the CentOS Security Response Team.
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 CentOS 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.
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