Security researchers have discovered a set of vulnerabilities in several vendors' implementations of the SSHv2 protocol that could give an attacker the ability to execute code on remote machines. The new flaws are especially dangerous in that they occur before authentication takes place.

The SSH (secure shell) protocol is a transport layer protocol that enables clients to connect securely to a remote server. It's often used for remote administration purposes.

Although the results of exploiting one of these vulnerabilities varies by vendor and vulnerability, attackers could, in some cases, run code on remote machines or launch denial-of-service attacks. Rapid 7 Inc., the New York-based security company that found the vulnerabilities, only tested SSHv2 implementations but said that some SSHv1 implementations may be vulnerable as well.

eWeek