A Citrix server is running on this machine. Citrix servers allow a Windows user to remotely obtain a graphical login (and therefore act as a local user on the remote host). NOTE: by default the Citrix Server application utilizes a weak 40 bit obfuscation algorithm (not even a true encryption). If the default settings have not been changed, there already exists tools which can be used to passively ferret userIDs and passwords as they traverse a network. If this server is located within your DMZ, the risk is substantially higher, as Citrix necessarily requires access into the internal network for applications like SMB browsing, file sharing, email synchronization, etc. If an attacker gains a valid login and password, he may be able to use this service to gain further access on the remote host or remote network. This protocol has also been shown to be vulnerable to a man-in-the-middle attack.
Disable this service if you do not use it. Also, make sure that the server is configured to utilize strong encryption.