Increased Traffic to 7100/udp

US-CERT is aware of a dramatic increase in inbound traffic to port 7100/udp over the past 48 hours.

7100/udp is used by multiple applications, most commonly X Font Server. X Font Server provides a mechanism for the X server to communicate with a font renderer and is commonly used on the X Window System. This increase in traffic is unusual as remote access to the X Font Server is not typically required for normal operations

US-CERT encourages administrators to block inbound traffic to port 7100/udp at the network perimeter. Please note, proper risk and impact analysis procedures should be followed prior to taking defensive measures.

US-CERT is currently investigating the nature of this activity and will provide updates as needed.