Synopsis
A remote control service is running on this port.
Description
UltraVNC seems to be running on the remote port.
Upon connection, the remote service on this port always sends the same 12 pseudo-random bytes.
It is probably UltraVNC with the old DSM encryption plugin. This plugin tunnels the RFB protocol into a RC4-encrypted stream.
This old protocol does not use a random IV so the RC4 pseudo random flow is reused from one session to another. An authenticated user could leverage this issue to decrypt other users' sessions.
Solution
If this service is not needed, disable it or filter incoming traffic to this port. Otherwise, upgrade UltraVNC and use one of the new and safer plugins which implement a random IV.
Plugin Details
File Name: ultravnc_dsm_detect.nasl
Configuration: Enable thorough checks
Supported Sensors: Nessus
Vulnerability Information
CPE: cpe:/a:uvnc:ultravnc