The remote host is missing an update to xonix announced via advisory DSA 484-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%20484-1

Steve Kemp discovered a vulnerability in xonix, a game, where an external program was invoked while retaining setgid privileges. A local attacker could exploit this vulnerability to gain gid 'games'. For the current stable distribution (woody) this problem will be fixed in version 1.4-19woody1. For the unstable distribution (sid), this problem will be fixed soon. We recommend that you update your xonix package.