Citrix SD-WAN Security Update

Multiple denial of service vulnerabilities have been identified in the Citrix SD-WAN Appliance and Citrix SD-WAN Center Management Console. These vulnerabilities could permit a remote attacker to cause a denial of service by causing a host crash or by causing reduced service capacity due to resource exhaustion. The vulnerabilities have been assigned the following CVE numbers.

• CVE-2019-11477: SACK Panic 
• CVE-2019-11478: SACK Slowness or Excess Resource Usage
• CVE-2019-11479: Excess Resource Consumption Due to Low MSS Values

In order to protect against these vulnerabilities and web application related issues, Citrix recommends access to the management console be restricted. In situations where customers have deployed their management console in line with industry best practice, network access to this interface should already be restricted.

Security Best Practices:

10.x - https://docs.citrix.com/en-us/netscaler-sd-wan/10/best-practices/security-best-practices.html

These vulnerabilities have been addressed in the following software versions: 

• NetScaler SD-WAN 10.0.8

• Citrix SD-WAN 10.2.4

• Citrix SD-WAN 11.0.1

Citrix recommends that customers using vulnerable software upgrade their management console to the new version or later as soon as possible.

Customers using versions of the product that will not contain a fix (i.e. 9.3.x) are advised to consider upgrading to a version that does contain the fix (i.e. 11.0.1)

The new software versions will be available on the Citrix website. Information on the available versions can be found at the following location:

https://www.citrix.com/downloads/netscaler-sd-wan/

In line with general best practice, Citrix also recommends that customers limit access to the management console of the Citrix SD-WAN Appliance and Citrix SD-WAN Center Management Console to trusted network traffic only.