The remote host is missing an update to proftpd-dfsg announced via advisory DSA 1727-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%201727-1

Two SQL injection vulnerabilities have been found in proftpd, a virtual-hosting FTP daemon. The Common Vulnerabilities and Exposures project identifies the following problems: CVE-2009-0542 Shino discovered that proftpd is prone to an SQL injection vulnerability via the use of certain characters in the username. CVE-2009-0543 TJ Saunders discovered that proftpd is prone to an SQL injection vulnerability due to insufficient escaping mechanisms, when multybite character encodings are used. For the stable distribution (lenny), these problems have been fixed in version 1.3.1-17lenny1. For the oldstable distribution (etch), these problems will be fixed soon. For the testing distribution (squeeze), these problems will be fixed soon. For the unstable distribution (sid), these problems have been fixed in version 1.3.2-1. We recommend that you upgrade your proftpd-dfsg package.