Updated openssh packages that fix several security issues in sshd are now
available for CentOS Linux 2.1.
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
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)
An arbitrary command execution flaw was discovered in the way scp copies
files locally. It is possible for a local attacker to create a file with a
carefully crafted name that could execute arbitrary commands as the user
running scp to copy files locally. (CVE-2006-0225)
The SSH daemon, when restricting host access by numeric IP addresses and
with VerifyReverseMapping disabled, allows remote attackers to bypass
"from=" and "user@host" address restrictions by connecting to a host from a
system whose reverse DNS hostname contains the numeric IP address.
All users of openssh should upgrade to these updated packages, which
contain backported patches that resolve these issues.