News

Flaw Found in Microsoft Enterprise Firewall

Microsoft's enterprise firewall contains a security hole that attackers could use to cause denial-of-service conditions in internal Domain Name Service servers. The security flaw with Internet Security & Acceleration Server rates as a "moderate" security risk, Microsoft security officials determined.

The security bulletin and patch were posted Wednesday night and are available at www.microsoft.com/technet/security/bulletin/MS03-009.asp.

The bulletin makes clear that the flaw cannot be used to take control of the ISA Server 2000 machine or servers behind the firewall that it protects. The flaw involves a feature of ISA Server that provides application-specific processing of incoming traffic. The feature is designed to protect against invalid URLs that are common to attacks against internal DNS servers.

The flaw involves ISA's DNS intrusion application filter, which improperly handles a specific type of request when scanning incoming DNS requests, the Microsoft bulletin states. An attacker could send a specially malformed request to the ISA Server that is publishing a DNS server. In turn, the attack could result in a denial of service to the published DNS server.

"DNS requests arriving at the ISA Server would be stopped at the firewall, and not passed through to the internal DNS server. All other ISA Server functionality would be unaffected," the bulletin states.

One important mitigating factor is that DNS servers are not published by default -- DNS publishing must be manually enabled in ISA Server.

About the Author

Scott Bekker is editor in chief of Redmond Channel Partner magazine.

Featured

  • How To Use .CSV Files with PowerShell, Part 1

    When it comes to bulk administration, few things are handier than .CSV files. In this two-part series, Brien demos his top techniques for working with .CSV files in PowerShell. First up: How to create a .CSV file.

  • SameSite Cookie Changes Rolled Back Until Summer

    The Chromium Project announced on Friday that it's delaying enforcement of SameSite cookie changes, and is temporarily rolling back those changes, because of the COVID-19 turmoil.

  • Basic Authentication Extended to 2H 2021 for Exchange Online Users

    Microsoft is now planning to disable Basic Authentication use with its Exchange Online service sometime in the "second half of 2021," according to a Friday announcement.

  • Microsoft Offers Endpoint Configuration Manager Advice for Keeping Remote Clients Patched

    Microsoft this week offered advice for organizations using Microsoft Endpoint Configuration Manager with remote Windows systems that need to get patched, and it also announced Update 2002.

comments powered by Disqus

Office 365 Watch

Sign up for our newsletter.

Terms and Privacy Policy consent

I agree to this site's Privacy Policy.