The Network Time Protocol (NTP) package contains a vulnerability that could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition. The vulnerability is due to an error in handling certain malformed messages. An unauthenticated, remote attacker could send a malicious NTP packet with a spoofed source IP address to a vulnerable host. Once the host processes the packet, it could send a similar packet to another NTP host. This action could start a message loop between both hosts that could cause them to consume excessive CPU resources and disk space writing messages to log files. These two conditions could cause a DoS condition on the affected hosts. Functional exploit code is available. NTP.org has confirmed this vulnerability in a changelog and released updated software. This vulnerability can be exploited in one of two ways. It can be used to attack a single system running NTP and cause it to send packets to itself. Alternatively, it could be used to target two systems running NTP. In this case, the two systems would rapidly send messages back and forth between each other, causing a DoS condition on each system as well as consuming network bandwidth to carry the messages.
The vulnerability is due to an error in handling certain malformed messages. An unauthenticated, remote attacker could send a malicious NTP packet with a spoofed source IP address to a vulnerable host. Once the host processes the packet, it could send a similar packet to another NTP host. This action could start a message loop between both hosts that could cause them to consume excessive CPU resources and disk space writing messages to log files. These two conditions could cause a DoS condition on the affected hosts.
Functional exploit code is available.
NTP.org has confirmed this vulnerability in a changelog and released updated software.
IBM has released APARs at the following links: IZ68659 and IZ71047
FreeBSD has released a security advisory at the following link: FreeBSD-SA-10:02
HP has released security bulletins c01961959, c01961950, c02737553, and c03714526 at the following links: HPSBOV02497 SSRT090245, HPSBTU02496 SSRT090245, HPSBUX02639 SSRT100293, and HPSBUX02859 SSRT101144
MontaVista Software has re-released a security alert for registered users on March 2, 2010, at the following link: MontaVista Security Fixes
NetBSD has released a security advisory at the following FTP link: NetBSD-SA2010-005
Nortel has released a security bulletin at the following link: 2009009932
Red Hat has released security advisories at the following links: RHSA-2009:1648 and RHSA-2009:1651
Sun has re-released an alert notification at the following link: 275590
US-CERT has released a vulnerability note at the following link: VU#568372
VMware has re-released security advisories at the following links: VMSA-2010-0009 and VMSA-2010-0004
Administrators are advised to take measures against spoofing at the perimeter firewall.
Administrators are advised to monitor affected systems.
CentOS packages can be updated using the up2date or yum command.
Cisco customers with active contracts can obtain updates through the Software Center at the following link: Cisco. Cisco customers without contracts can obtain upgrades by contacting the Cisco Technical Assistance Center at 1-800-553-2447 or 1-408-526-7209 or via email at tac@cisco.com.
FreeBSD has released patches at the following HTTP link: ntpd.patch
HP has released updated software at the following links:
Itanium Images
V55_ECO3 (NTP Patch)
V56_ECO4 (NTP Patch)Alpha Images
V55_ECO3 (NTP Patch)
V56_ECO4 (NTP Patch)Tru64 UNIX
v5.1B-5 PK7 (NTP Patch)
v5.1B-4 PK6 (NTP Patch)
HP-UX
HP-UX B.11.31 NTP version 4
HP customers are advised to acquire the patches via normal HP support channels.
MontaVista Software has released updated software for registered users at the following links:
PRO 5.0.24
PRO 5.0
PRO 4.0.1
CGE 4.0.1
MOBILINUX 5.0.24
MOBILINUX 4.1
MOBILINUX 4.0.2
MVL 5
MOBILINUX 5.0
CGE 5.1
NetBSD has released information on obtaining source code patches at the following FTP link: NetBSD
Nortel has released information about updated software at the following link: 2009009932
Red Hat packages can be updated using the up2date or yum command.
Sun has released updated software for registered users at the following links:
SPARC
Solaris 9 with patch 117143-02 or later
Solaris 10 xntpd (SUNWntpu) with patch 127724-02 or later
Solaris 10 ntpd (SUNWntp4u) with patch 143725-01 or laterIntel
Solaris 9 with patch 117144-02 or later
Solaris 10 xntpd (SUNWntpu) with patch 127725-02 or later
Solaris 10 ntpd (SUNWntp4u) with patch 143726-01 or later
VMware has released updated software at the following links:
ESXi 4.0
ESXi400-201005401-SGESXi 3.5
ESXe350-201006401-I-SGESX 4.0
ESX400-201005404-SGESX 3.5
ESX350-201006407-SG
VMware vMA 4.0 can be updated to Patch 3 using the sudo /usr/sbin/vima-update update command.
The Cisco Product Security Incident Response Team (PSIRT) is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory.
To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy. This document also contains instructions for obtaining fixed software and receiving security vulnerability information from Cisco.
| Version | Description | Section | Status | Date |
| 19.0 | HP has released an additional security bulletin and updated software to address the Network Time Protocol package remote message loop denial of service vulnerability. | NA | Final | 2013-Mar-28 |
| 18.0 | HP has released an additional security bulletin and updated software to address the Network Time Protocol package remote message loop denial of service vulnerability. | NA | Final | 2011-Apr-04 |
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