The remote host is missing an update to maildrop announced via advisory DSA 1981-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%201981-1

Christoph Anton Mitterer discovered that maildrop, a mail delivery agent with filtering abilities, is prone to a privilege escalation issue that grants a user root group privileges. For the stable distribution (lenny), this problem has been fixed in version 2.0.4-3+lenny1. For the oldstable distribution (etch), this problem has been fixed in version 2.0.2-11+etch1. For the testing distribution (squeeze) and the unstable distribution (sid), this problem will be fixed soon. We recommend that you upgrade your maildrop packages.