The remote host is missing an update to hanterm announced via advisory DSA 112-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%20112-1

A set of buffer overflow problems have been found in hanterm, a Hangul terminal for X11 derived from xterm, that will read and display Korean characters in its terminal window. The font handling code in hanterm uses hard limited string variables but didn't check for boundaries. This problem can be exploited by a malicious user to gain access to the utmp group which is able to write the wtmp and utmp files. These files record login and logout activities. This problem has been fixed in version 3.3.1p17-5.2 for the stable Debian distribution. A fixed package for the current testing/unstable distribution is not yet available but will have a version number higher than 3.3.1p18-6.1. We recommend that you upgrade your hanterm packages immediately if you