Invalid RDP Data Can Cause Memory Leak in Terminal Services New

A security vulnerability exists in Windows 2000 and Windows NT 4.0 Terminal servers which could allow a malicious user to cause a denial of service attack by flooding port 3389.

Issue

The Windows 2000 Terminal Service and Windows NT 4.0 Terminal Server Edition contains a memory leak in one of the functions that processes incoming Remote Data Protocol data via port 3389. Each time an RDP packet containing a specific type of malformation is processed, the memory leak depletes overall server memory by a small amount.

If an attacker sent a sufficiently large quantity of such data to an affected machine, he could deplete the machine's memory to the point where response time would be slowed or the machine's ability to respond would be stopped altogether. All system services would be affected, including but not limited to terminal services. Normal operation could be restored by rebooting the machine.

Affected Products

• Microsoft® Windows® 2000 and Windows NT 4.0 Terminal servers

Solution

A software patch is available from the following locations:

• Windows NT 4.0, Terminal Server Edition
• Windows 2000

Further Details

Source: Microsoft Corporation

Reference: Microsoft Corporation

Updated: July 25, 2001

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