NTP: Denial of Service

1. Gentoo Linux Security Advisory

Advisory Reference	GLSA 201001-01 / ntp
Release Date	January 03, 2010
Latest Revision	January 03, 2010: 01
Impact	normal
Exploitable	remote

Package	Vulnerable versions	Unaffected versions	Architecture(s)
net-misc/ntp	< 4.2.4_p7-r1	>= 4.2.4_p7-r1	All supported architectures

Related bugreports: #290881

Synopsis

A Denial of Service condition in ntpd can cause excessive CPU or bandwidth consumption.

2. Impact Information

Background

NTP is a set of the Network Time Protocol programs.

Description

Robin Park and Dmitri Vinokurov discovered that ntp_request.c in ntpd does not handle MODE_PRIVATE packets correctly, causing a continuous exchange of MODE_PRIVATE error responses between two NTP daemons or causing high CPU load on a single host.

Impact

A remote, unauthenticated attacker could send a specially crafted MODE_PRIVATE packet, allowing for a Denial of Service condition (CPU and bandwidth consumption).

3. Resolution Information

Workaround

There is no known workaround at this time.

Resolution

All NTP users should upgrade to the latest version:

Code Listing 3.1: Resolution

# emerge --sync
# emerge --ask --oneshot --verbose ">=net-misc/ntp-4.2.4_p7-r1"

4. References

CVE-2009-3563

Page updated January 03, 2010

Summary: This is a Gentoo Linux Security Advisory

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