Vulnerability Note VU#865833

Microsoft Windows Remote Desktop Protocol (RDP) uses weak algorithm for encrypting packets

Original Release date: 06 Dec 2002 | Last revised: 06 Dec 2002

Overview

Microsoft Windows Remote Desktop Protocol (RDP) uses a weak algorithm for encrypting packets.

Description

Microsoft describes RDP as follows.

    RDP is based on, and is an extension of, the T.120 protocol family standards. It is a multichannel-capable protocol that allows for separate virtual channels for carrying device communication and presentation data from the server, as well as encrypted client mouse and keyboard data.

Microsoft's implementation of RDP does not encrypt the checksums of the session data. Therefore, a determined attacker could apply cryptanalytic techniques to recover encrypted session traffic. Note that Microsoft has listed the following mitigating factors:
    An attacker would need the ability to capture an RDP session in order to exploit this vulnerability. In most cases, this would require that the attacker have physical access to the network media.

    Because encryption keys are negotiated on a per-session basis, a successful attack would allow an attacker to decrypt only a single session and not multiple sessions. Thus, the attacker would need to conduct a separate cryptanalytic attack against each session he or she wished to compromise.

Impact

A remote attacker could apply cryptanalytic techniques to recover encrypted session traffic.

Solution

Apply a patch.

Systems Affected (Learn More)

VendorStatusDate NotifiedDate Updated
Microsoft CorporationAffected-06 Dec 2002
If you are a vendor and your product is affected, let us know.

CVSS Metrics (Learn More)

Group Score Vector
Base N/A N/A
Temporal N/A N/A
Environmental N/A N/A

References

Credit

Ben Cohen & Pete Chown of Skygate Technology Ltd. discovered this vulnerability.

This document was written by Ian A Finlay.

Other Information

  • CVE IDs: CAN-2002-0863
  • Date Public: 18 Sep 2002
  • Date First Published: 06 Dec 2002
  • Date Last Updated: 06 Dec 2002
  • Severity Metric: 6.30
  • Document Revision: 16

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