The remote Debian host is missing a security-related update.
Two vulnerabilities were discovered in OpenSSH, an implementation of the SSH protocol suite. The Common Vulnerabilities and Exposures project identifies the following problems : - CVE-2014-2532 Jann Horn discovered that OpenSSH incorrectly handled wildcards in AcceptEnv lines. A remote attacker could use this issue to trick OpenSSH into accepting any environment variable that contains the characters before the wildcard character. - CVE-2014-2653 Matthew Vernon reported that if a SSH server offers a HostCertificate that the ssh client doesn't accept, then the client doesn't check the DNS for SSHFP records. As a consequence a malicious server can disable SSHFP-checking by presenting a certificate. Note that a host verification prompt is still displayed before connecting.
Upgrade the openssh packages. For the oldstable distribution (squeeze), these problems have been fixed in version 1:5.5p1-6+squeeze5. For the stable distribution (wheezy), these problems have been fixed in version 1:6.0p1-4+deb7u1.