The remote host is missing an update to hylafax announced via advisory DSA 634-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%20634-1

Patrice Fournier discovered a vulnerability in the authorisation subsystem of hylafax, a flexible client/server fax system. A local or remote user guessing the contents of the hosts.hfaxd database could gain unauthorised access to the fax system. Some installations of hylafax may actually utilise the weak hostname and username validation for authorized uses. For example, hosts.hfaxd entries that may be common are 192.168.0 username:uid:pass:adminpass user@host After updating, these entries will need to be modified in order to continue to function. Respectively, the correct entries should be 192.168.0.[0-9]+ username@:uid:pass:adminpass user@host Unless such maching of username with otherusername and host with hostname is desired, the proper form of these entries should include the delimiter and markers like this @192.168.0.[0-9]+$ ^username@:uid:pass:adminpass ^user@host$ For the stable distribution (woody) this problem has been fixed in version 4.1.1-3.1. For the unstable distribution (sid) this problem has been fixed in version 4.2.1-1. We recommend that you upgrade your hylafax packages.