Zero-Day Advisory

Fortinet Discovers Microsoft Windows Server WINS Server Remote Memory Corruption Vulnerability

Summary

Fortinet's FortiGuard Labs has discovered a memory corruption vulnerability in WINS Server service running in Microsoft Windows Server.

Windows Internet Name Service (WINS) is a legacy computer name registration and resolution service that maps computer NetBIOS names to IP addresses. When WINS servers are deployed on the network, end users can access network resources by name rather than by harder-to-remember IP addresses.

The memory corruption vulnerability exists due to incorrectly handling of multiple pending WINS-Replication sessions. An attacker can exploit this vulnerability to launch denial-of-service attack by sending crafted network packets to crash WINS Server service.

Solutions

FortiGuard Labs released the following FortiGate IPS signature which covers this specific vulnerability:

MS.Windows.WINS.Server.Remote.Memory.Corruption
Released Feb 21, 2017

Microsoft will not patch this vulnerability due to the amount of work that would be required. Instead, Microsoft is recommending users replace WINS with DNS.

Additional Information

Following products are affected by the vulnerability:

Windows Server 2008

Windows Server 2012

Windows Server 2016

References

• https://docs.microsoft.com/en-us/windows-server/networking/technologies/wins/wins-top
  

Acknowledgement

This vulnerability was discovered by Honggang Ren of Fortinet's FortiGuard Labs.

IPS Subscription

Fortinet customers who subscribe to Fortinet's intrusion prevention (IPS) service should be protected against this vulnerability with the appropriate configuration parameters in place. Fortinet's IPS service is one component of FortiGuard Subscription Services, which also offer comprehensive solutions such as antivirus, Web content filtering and antispam capabilities. These services enable protection against threats on both application and network layers. FortiGuard Services are continuously updated by FortiGuard Labs, which enables Fortinet to deliver a combination of multi-layered security intelligence and true zero-day protection from new and emerging threats. These updates are delivered to all FortiGate, FortiMail and FortiClient products. Fortinet strictly follows responsible disclosure guidelines to ensure optimum protection during a threat's lifecycle.