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Stable Release NEWS

Focus: Security Fixes

Severity: HIGH

This release fixes the following high-severity vulnerability:

• [Sec 1331] DoS with mode 7 packets - CVE-2009-3563.

See http://support.ntp.org/security for more information.

NTP mode 7 (MODE_PRIVATE) is used by the ntpdc query and control utility. In contrast, ntpq uses NTP mode 6 (MODE_CONTROL), while routine NTP time transfers use modes 1 through 5. Upon receipt of an incorrect mode 7 request or a mode 7 error response from an address which is not listed in a restrict ... noquery or restrict ... ignore statement, ntpd will reply with a mode 7 error response (and log a message). In this case:

• If an attacker spoofs the source address of ntpd host A in a mode 7 response packet sent to ntpd host B, both A and B will continuously send each other error responses, for as long as those packets get through.

• If an attacker spoofs an address of ntpd host A in a mode 7 response packet sent to ntpd host A, A will respond to itself endlessly, consuming CPU and logging excessively.

Credit for finding this vulnerability goes to Robin Park and Dmitri Vinokurov of Alcatel-Lucent.

Complete NEWS file
Complete Change Log

About the NTP Source Releases and Patches

The NTP (R&D) Project only produces source code releases of NTP; users needing precompiled versions of NTP should see the links page. These releases may be installed using the standard Unix "make" command in conjunction with a compiler and all necessary libraries.

Please contact your operating system vendor for binary packages or assistance with your package-management system.

The NTP version numbering page explains the version numbering scheme.

NTP Archives from the NTP (R&D) Project at www.ntp.org

Tarballs (for both the release and development versions) and patch files are available from the:

• NTP (R&D) Project HTTP archive.
• NTP (R&D) Project FTP archive

Obsolete versions of NTP are available from the:

• NTP (R&D) Project Deprecated HTTP archive.
• NTP (R&D) Project Deprecated FTP archive

Access to the FTP archive is restricted; incoming connections from certain IP addresses are blocked by the organization hosting the NTP (R&D) Project archives. Please try the HTTP archive if you are unable to access the FTP archive.

Precompiled packages and ports to other operating systems

Third-party implementations, including pre-compiled versions for operating systems such as Microsoft Windows, and some ports of the NTP package are linked to on the links page.

Receiving Notifications about new releases

Please visit ReleaseNotifications for more information about the many options available for receiving notifications about new NTP releases.