The remote host is missing an update to the system as announced in the referenced advisory.
The following package is affected: squid
CVE-2005-0173 squid_ldap_auth in Squid 2.5 and earlier allows remote authenticated users to bypass username-based Access Control Lists (ACLs) via a username with a space at the beginning or end, which is ignored by the LDAP server.
Solution: Update your system with the appropriate patches or software upgrades.