Q

Are rogue DHCP servers a serious network risk?

Rogue DHCP servers can cause everything from a network outage to an outright interception of network traffic. In this SearchSecurity.com Q&A, network security expert Mike Chapple explains the seriousness of the threat and reveals which tools can detect rogue servers.

What risk does a rogue DHCP server pose to a network? Is it a security issue or a nuisance?
Rogue Dynamic Host Configuration Protocol ( DHCP) servers are definitely a security issue. Networks use DHCP servers to provide systems with network configuration information. For example, a host might contact a DHCP server to obtain an IP address, default gateway and domain name system (DNS) server information.

Suppose an individual were able to introduce a malicious DHCP server into your environment. That server could then

wreak all sorts of havoc on your network. In the best case, it could simply offer every client an identical IP address, resulting in a network outage when all hosts believe they were leased the same address. In the worst case, the rogue server could set the default gateway to be the IP address of an attacker's proxy server. In such a scenario, an attacker could intercept all traffic leaving the host.

For this reason, it's important to ensure that you don't have rogue DHCP servers on your network. Microsoft's DHCP Server Location Utility is a great tool that allows you to search your network for active DHCP servers. You can also provide it with a list of authorized DHCP servers and configure it to alert you immediately if a rogue server is detected. Due to the risks described above, you should take action to immediately disconnect any rogue servers on your network.

More information:

  • In this new Intrusion Defense School lesson, Tom Bowers explains how SIMs can increase your network visibility.
  • Learn other ways to detect a rogue DHCP server.
  • This was first published in April 2007

    Dig deeper on Monitoring Network Traffic and Network Forensics

    Pro+

    Features

    Enjoy the benefits of Pro+ membership, learn more and join.

    Have a question for an expert?

    Please add a title for your question

    Get answers from a TechTarget expert on whatever's puzzling you.

    You will be able to add details on the next page.

    0 comments

    Oldest 

    Forgot Password?

    No problem! Submit your e-mail address below. We'll send you an email containing your password.

    Your password has been sent to:

    SearchCloudSecurity

    SearchNetworking

    SearchCIO

    SearchConsumerization

    SearchEnterpriseDesktop

    SearchCloudComputing

    ComputerWeekly

    Close