You are running a version of OpenSSH which is older than 3.0.2. Versions prior than 3.0.2 are vulnerable to an environment variables export that can allow a local user to execute command with root privileges. This problem affect only versions prior than 3.0.2, and when the UseLogin feature is enabled (usually disabled by default)

Upgrade to OpenSSH 3.0.2 or apply the patch for prior versions. (Available at: ftp://ftp.openbsd.org/pub/OpenBSD/OpenSSH)