Buffer overflow in Citrix Netscaler ADC and Citrix NetScaler Gateway - CVE-2023-4966

Detailed vulnerability description

The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to a boundary error. A remote non-authenticated attacker can send specially crafted data to the device, trigger memory corruption and execute arbitrary code on the target system.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system but requires that the appliance is configured as a Gateway (VPN virtual server, ICA Proxy, CVPN, RDP Proxy) or as AAAvirtualserver.

Note, the vulnerability is being actively exploited in the wild since August 2023.

How to mitigate CVE-2023-4966

Install updates from vendor's website.

For FIPS releases install the following versions:

• NetScaler ADC 13.1-FIPS version 13.1-37.164
• NetScaler ADC 12.1-FIPS version 12.1-55.300
• NetScaler ADC 12.1-NDcPP version 12.1-55.300

Sources

• https://support.citrix.com/article/CTX579459
• https://www.mandiant.com/resources/blog/remediation-netscaler-adc-gateway-cve-2023-4966