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Line 1: − + + − It is important to note that the same exploits may well apply to IPv4 hosts running the same protocols.+ + + + + + + + + − + − + − 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 version 4.2.7, add the “noquery” directive to the “restrict default” line in the system’s ntpd.conf, as shown below: Line 24:
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→Links to other material
==IPv6 Special Tests==
==IPv6 Special Tests==
IPscan includes the following tests to exercise known weak protocols, or protocols which when poorly configured, can be exploited.
IPscan includes the following tests to identify known weak protocols or poorly configured services, which may be exploited.
It is important to note that the same exploits may well apply to IPv4 hosts running the same protocols.
===Links to other material===
* [[IPv6]] - an overview of IPscan (IPv6 Port Scanner)
* [[IPv6_Firewalls]] - some observations on IPv6 firewalls and address selections
* [[IPv6_Ports]] - a list of the default TCP/IP and UDP/IP ports which IPscan will test
* [[ScanStatus]] - a description of the reportable states for each tested TCP/IP or UDP/IP port
* [[ScanAutomation]] - a quick overview of IPv6 TCP/UDP port scan automation using wget
* [[IPv6_DEBUG]] - some steps for debugging IPv6 access to the IPscan IPv6 Port Scanner
* [[IPv6_Windows7]] - some useful Win7 IPv6-related commands
* [[Raspberry_Pi_IPv6_firewall_tester]] - a quick HowTo describing the steps to make your own RasPi-powered IPv6 firewall tester.
===NTP Monitor List Query '''UDP/161[1]'''===
===NTP Monitor List Query '''UDP/123[1]'''===
The NTP protocol, in earlier versions, supported a feature which reported a list of up to 600 clients which had used the queried NTP server as their time reference.
The NTP protocol daemon, in versions prior to 4.2.7, supported a feature which reported a list of up to 600 clients which had used the queried NTP server as their time reference.
If an attacker uses a spoofed source address then a victim can be flooded with considerable NTP traffic. The size of the response is typically considerably larger than the request and consequently 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.
If an attacker uses a spoofed source address then a victim can be flooded with considerable NTP traffic. The size of the response is typically considerably larger than the request and consequently 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.
To prevent your NTP daemon being used in DDoS attacks it is necessary to disable “monlist” functionality. On a public-facing NTP server that cannot be updated to version 4.2.7 or later, add the “noquery” directive to the “restrict default” line in the system’s ntpd.conf, as shown below:
<pre>
<pre>
See [http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-5211 CVE-2013-5211] for further details.
See [http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-5211 CVE-2013-5211] for further details.
===SNMP Queries '''UDP/161'''===
IPscan performs three SNMP queries. SNMP supports a variety of versions and authentication methods and since IPscan cannot know the credentials to use to test your system it defaults to using commonly-used, and therefore '''''insecure''''', community strings.
<TABLE border="1" style="width:300px">
<TR><TH>Port/Special Case</TH><TH>SNMP version</TH><TH>Test performed, credentials used</TH></TR>
<TR><TD>UDP/161</TD><TD>v1</TD><TD>GET with 'public' community string</TD></TR>
<TR><TD>UDP/161[1]</TD><TD>v2c</TD><TD>GET with 'private' community string</TD></TR>
<TR><TD>UDP/161[2]</TD><TD>v3</TD><TD>EngineID Discovery, credentials not required</TD></TR>
</TABLE>
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