Executive Summary

Informations
Name TA14-013A First vendor Publication 2014-01-13
Vendor US-CERT Last vendor Modification 2014-01-14
Severity (Vendor) N/A Revision N/A

Security-Database Scoring CVSS v3

Cvss vector : N/A
Overall CVSS Score NA
Base Score NA Environmental Score NA
impact SubScore NA Temporal Score NA
Exploitabality Sub Score NA
 
Calculate full CVSS 3.0 Vectors scores

Security-Database Scoring CVSS v2

Cvss vector : (AV:N/AC:L/Au:N/C:N/I:N/A:P)
Cvss Base Score 5 Attack Range Network
Cvss Impact Score 2.9 Attack Complexity Low
Cvss Expoit Score 10 Authentication None Required
Calculate full CVSS 2.0 Vectors scores

Detail

Overview

A Network Time Protocol (NTP) Amplification attack is an emerging form of Distributed Denial of Service (DDoS) that relies on the use of publically accessible NTP servers to overwhelm a victim system with UDP traffic.

Description

The NTP service supports a monitoring service that allows administrators to query the server for traffic counts of connected clients. This information is provided via the “monlist” command. The basic attack technique consists of an attacker sending a "get monlist" request to a vulnerable NTP server, with the source address spoofed to be the victim’s address.

Impact

The attack relies on the exploitation of the 'monlist' feature of NTP, as described in CVE-2013-5211, which is enabled by default on older NTP-capable devices. This command causes a list of the last 600 IP addresses which connected to the NTP server to be sent to the victim. Due to the spoofed source address, when the NTP server sends the response it is sent instead to the victim. Because the size of the response is typically considerably larger than the request, the attacker is able to amplify the volume of traffic directed at the victim. Additionally, because the responses are legitimate data coming from valid servers, it is especially difficult to block these types of attacks. The solution is to disable “monlist” within the NTP server or to upgrade to the latest version of NTP (4.2.7) which disables the “monlist” functionality.

Solution

Detection

On a UNIX-platform, the command “ntpdc” will query existing NTP servers for monitoring data. If the system is vulnerable to exploitation, it will respond to the “monlist” command in interactive mode. By default, most modern UNIX and Linux distributions allow this command to be used from localhost, but not from a remote host. To test for monlist support, execute the following command at the command line:

/usr/sbin/ntpdc <remote server>

monlist

Additionally, the “ntp-monlist” script is available for NMap, which will automatically display the results of the monlist command. If the system does not support the monitor query, and is therefore not vulnerable to this attack type, NMap will return an error type 4 (No Data Available) or no reply at all.

 

Recommended Course of Action

As all versions of ntpd prior to 4.2.7 are vulnerable by default, the simplest recommended course of action is to upgrade all versions of ntpd that are publically accessible to at least 4.2.7. However, in cases where it is not possible to upgrade the version of the service, it is possible to disable the monitor functionality in earlier versions of the software.

To disable “monlist” functionality on a public-facing NTP server that cannot be updated to 4.2.7, add the “noquery” directive to the “restrict default” line in the system’s ntp.conf, as shown below:

restrict default kod nomodify notrap nopeer noquery

restrict -6 default kod nomodify notrap nopeer noquery

Original Source

Url : http://www.us-cert.gov/cas/techalerts/TA14-013A.html

CWE : Common Weakness Enumeration

% Id Name
100 % CWE-20 Improper Input Validation

OVAL Definitions

Definition Id: oval:org.mitre.oval:def:24449
 
Oval ID: oval:org.mitre.oval:def:24449
Title: Network Time Protocol (NTP) vulnerability in AIX
Description: The monlist feature in ntp_request.c in ntpd in NTP before 4.2.7p26 allows remote attackers to cause a denial of service (traffic amplification) via forged (1) REQ_MON_GETLIST or (2) REQ_MON_GETLIST_1 requests, as exploited in the wild in December 2013.
Family: unix Class: vulnerability
Reference(s): CVE-2013-5211
Version: 6
Platform(s): IBM AIX 6.1
IBM AIX 7.1
Product(s):
Definition Synopsis:
Definition Id: oval:org.mitre.oval:def:26210
 
Oval ID: oval:org.mitre.oval:def:26210
Title: SUSE-SU-2014:0937-1 -- Security update for ntp
Description: The NTP time service could have been used for remote denial of service amplification attacks.
Family: unix Class: patch
Reference(s): SUSE-SU-2014:0937-1
CVE-2013-5211
Version: 3
Platform(s): SUSE Linux Enterprise Server 11
SUSE Linux Enterprise Desktop 11
Product(s): ntp
Definition Synopsis:

CPE : Common Platform Enumeration

TypeDescriptionCount
Application 1
Os 1

ExploitDB Exploits

id Description
2014-04-28 NTP ntpd monlist Query Reflection - Denial of Service

Snort® IPS/IDS

Date Description
2018-05-23 SSDP M-SEARCH ssdp-all potential amplified distributed denial-of-service attempt
RuleID : 45157-community - Revision : 4 - Type : SERVER-OTHER
2018-01-11 SSDP M-SEARCH ssdp-all potential amplified distributed denial-of-service attempt
RuleID : 45157 - Revision : 4 - Type : SERVER-OTHER
2015-05-19 NTP mode 6 UNSETTRAP denial of service attempt
RuleID : 34114 - Revision : 4 - Type : SERVER-OTHER
2015-05-19 NTP mode 6 REQ_NONCE denial of service attempt
RuleID : 34112 - Revision : 4 - Type : SERVER-OTHER
2014-02-15 ntp monlist denial of service attempt
RuleID : 29393 - Revision : 6 - Type : SERVER-OTHER

Nessus® Vulnerability Scanner

Date Description
2017-10-27 Name : The remote OracleVM host is missing one or more security updates.
File : oraclevm_OVMSA-2017-0165.nasl - Type : ACT_GATHER_INFO
2017-02-08 Name : The remote OracleVM host is missing one or more security updates.
File : oraclevm_OVMSA-2017-0038.nasl - Type : ACT_GATHER_INFO
2016-09-13 Name : The remote Oracle Linux host is missing one or more security updates.
File : oraclelinux_ELSA-2016-3613.nasl - Type : ACT_GATHER_INFO
2016-09-13 Name : The remote Oracle Linux host is missing one or more security updates.
File : oraclelinux_ELSA-2016-3612.nasl - Type : ACT_GATHER_INFO
2015-12-30 Name : The remote VMware ESX / ESXi host is missing a security-related patch.
File : vmware_VMSA-2014-0002_remote.nasl - Type : ACT_GATHER_INFO
2015-05-22 Name : The remote VMware ESXi 5.5 host is affected by multiple vulnerabilities.
File : vmware_esxi_5_5_build_1623387_remote.nasl - Type : ACT_GATHER_INFO
2015-01-29 Name : The remote VMware ESXi 5.1 host is affected by multiple vulnerabilities.
File : vmware_esxi_5_1_build_1743201_remote.nasl - Type : ACT_GATHER_INFO
2015-01-29 Name : The remote VMware ESXi 5.0 host is affected by multiple vulnerabilities.
File : vmware_esxi_5_0_build_1749766_remote.nasl - Type : ACT_GATHER_INFO
2015-01-19 Name : The remote Solaris system is missing a security patch for third-party software.
File : solaris11_ntp_20140417.nasl - Type : ACT_GATHER_INFO
2014-09-19 Name : The remote device is missing a vendor-supplied security patch.
File : juniper_jsa10613.nasl - Type : ACT_GATHER_INFO
2014-08-01 Name : The remote openSUSE host is missing a security update.
File : openSUSE-2014-474.nasl - Type : ACT_GATHER_INFO
2014-07-31 Name : The remote openSUSE host is missing a security update.
File : suse_12_3_openSUSE-2014--140722.nasl - Type : ACT_GATHER_INFO
2014-07-31 Name : The remote openSUSE host is missing a security update.
File : suse_13_1_openSUSE-2014--140722.nasl - Type : ACT_GATHER_INFO
2014-07-30 Name : The remote SuSE 11 host is missing one or more security updates.
File : suse_11_ntp-140721.nasl - Type : ACT_GATHER_INFO
2014-06-17 Name : The remote AIX host is missing a security patch.
File : aix_IV59636.nasl - Type : ACT_GATHER_INFO
2014-06-17 Name : The remote AIX host is missing a security patch.
File : aix_IV58413.nasl - Type : ACT_GATHER_INFO
2014-06-17 Name : The remote AIX host is missing a security patch.
File : aix_IV58068.nasl - Type : ACT_GATHER_INFO
2014-06-17 Name : The remote AIX host is missing a security patch.
File : aix_IV56575.nasl - Type : ACT_GATHER_INFO
2014-06-17 Name : The remote AIX host is missing a security patch.
File : aix_IV56324.nasl - Type : ACT_GATHER_INFO
2014-06-17 Name : The remote AIX host is missing a security patch.
File : aix_IV56213.nasl - Type : ACT_GATHER_INFO
2014-06-17 Name : The remote AIX host is missing a security patch.
File : aix_IV55365.nasl - Type : ACT_GATHER_INFO
2014-03-12 Name : The remote VMware ESXi / ESX host is missing one or more security-related pat...
File : vmware_VMSA-2014-0002.nasl - Type : ACT_GATHER_INFO
2014-02-14 Name : The remote Slackware host is missing a security update.
File : Slackware_SSA_2014-044-02.nasl - Type : ACT_GATHER_INFO
2014-01-20 Name : The remote Gentoo host is missing one or more security-related patches.
File : gentoo_GLSA-201401-08.nasl - Type : ACT_GATHER_INFO
2014-01-15 Name : The remote FreeBSD host is missing a security-related update.
File : freebsd_pkg_3d95c9a77d5c11e3a8c1206a8a720317.nasl - Type : ACT_GATHER_INFO
2014-01-02 Name : The remote NTP server is affected by a denial of service vulnerability.
File : ntp_monlist_enabled.nasl - Type : ACT_GATHER_INFO

Alert History

If you want to see full details history, please login or register.
0
1
Date Informations
2014-03-06 13:30:16
  • Multiple Updates
2014-01-14 17:18:19
  • First insertion