Thus, ingress filtering should be performed at the border to prohibit externally initiated inbound traffic to non-authorized servicesĥ For SNMP, ingress filtering of the following ports listed below can prevent attackers outside of your network from impacting vulnerable devices in the local network that are not explicitly authorized to provide public SNMP services. In the typical network operation of many sites, there are few reasons for external hosts to initiate inbound traffic to machines that provide no public services. Servers are typically the only machines that need to accept inbound traffic from the public Internet. Ingress filtering manages the flow of traffic as it enters a network that is under your administrative control. Figure 2 Ingress Network Protection You can further limit SNMP vulnerabilities by blocking access to SNMP services at the network perimeter or firewall. By clicking on the Filter IP link (see highlight in Figure 2 for link location) you can view the Direction, Action, Destination IP, and Default for Dial-in settings recommended by Patton. The diagram below shows the Filter IP window of the RAS management software. #Download Smartnode Discovery Tool download#For additional information about using filters in the Patton RAS click on the link below to download our IP Filters overview. Creating filters for this purpose is sound practice for any installation and highly recommended by Patton. #Download Smartnode Discovery Tool software#Figure 1 Using Patton s web-based management system, under the SNMP page shown in Figure 1, Network Managers can identify possible denial-of-service (DOS) attacks by monitoring the following items: # Number of inbound packets ( Packets In ) # Bad Community Names # Bad Community Uses # Error Status Too Big - 3 -Ĥ Prevention Dial-in Users The Patton RAS software suite enables filters to be applied to dial-in users that will prevent any type of IP access to the RAS. Figure 1 shows the results of the test and demonstrates the Patton RAS s ability to withstand a serious SNMP attack. The Patton RAS under test logged over 3.5 million SNMP transactions without compromised operation. The free-running batch file used in the test sent 19,000 GET requests, invalid OID requests, and improper community strings every 5 seconds for several hours. Test results indicated that the Patton RAS products are not vulnerable to SNMP attacks. # Model 2800 # Model 2810 # Model 2860 # Model Port RAS # Model Port RAS # Model Port RAS # Model Port RAS # Model Port RAS # Model Port RAS # Model Port RAS - 2 -ģ Initial Determination The Patton technical support team performed initial testing using Solarwinds SNMP Brute Force Attack software with a free-running batch file. The following models of Patton RAS servers employ SNMP V1. Patton Electronics chassis-based Remote Access Server (RAS) products which are Layer-3 Internet appliances are equipped with SNMP. As such, they are not susceptible to upper-layer attacks. Patton Technical Support contact info: Tel: Fax: WWW:Ģ Products Affected Most of Patton s products are Layer-1 or Layer-2 devices. As a Patton customer, our Technical Services Team is available to help you implement the recommended configuration changes. In addition to this advisory, we recommend reading the following FAQ available at It is very important that you take the steps described in this document to address SNMP security vulnerabilities. The following provisions recommended by CERT and Patton Electronics Company should be employed in the operation of Patton s chassis-based RAS. If your site uses SNMP in any capacity, the CERT/CC encourages you to read this advisory and follow the advice provided in the Solutions section. These vulnerabilities may allow unauthorized privileged access, denial-of-service attacks, or cause system instability. Vulnerabilities have been reported in multiple vendors SNMP implementations. Patton is working with CERT to assess and address this issue. 1 SECURITY ADVISORY FROM PATTON ELECTRONICS Potential Security Vulnerabilities Identified in Simple Network Management Protocol (SNMP) Revision 1.0 For Public Release MaLast Updated MaContact Information Patton Electronics Co Rickenbacker drive Gaithersburg, MD Phone Fax Summary The CERT Coordination Center (CERT/CC) has issued a broad-based Alert to the technology industry regarding potential security vulnerabilities identified in the Simple Network Management Protocol (SNMP).
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