Title: Invalid RDP Data Can Cause Memory Leak in Terminal
Services
Date: 25 July 2001
Software: Windows 2000 Server and Windows NT 4.0, Terminal Server
Edition
Impact: Denial of Service
Bulletin: MS01-040

Microsoft encourages customers to review the Security Bulletin at:
http://www.microsoft.com/technet/security/bulletin/MS01-040.asp.

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.

Mitigating Factors:

• Normal firewalling could be used to prevent an attacker from
  exploiting
  this vulnerability from the Internet. Specifically, blocking port
  3389
  would prevent an attacker from delivering data to the affected
  service,
  thereby preventing him from exploiting the vulnerability.

• There is no capability to compromise data or usurp privileges via
  the
  vulnerability.

Patch Availability:

• A patch is available to fix this vulnerability. Please read the
  Security Bulletin
  http://www.microsoft.com/technet/security/bulletin/ms01-040.asp
  for information on obtaining this patch.

Acknowledgment:

• Peter Grundl

THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED
"AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL
WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT
SHALL
MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES
WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL,
LOSS
OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION
OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH
DAMAGES.
SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR
CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY
NOT
APPLY.