Zero-day vulnerability in Citrix NetScaler Gateway

Buffer overflow
CVE-2023-6549

Vulnerability details

Advisory: SB2024011635 - Multiple vulnerabilities in Citrix NetScaler ADC and NetScaler Gateway

Vulnerable component: Citrix NetScaler Gateway

CVE-ID: CVE-2023-6549

CVSSv3 score: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:H/RL:O/RC:C

CWE-ID: CWE-119 - Memory corruption

Description:

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to a boundary error. A remote attacker can send specially crated packets to the system, trigger memory corruption and perform a denial of service (DoS) attack.

Successful exploitation of this vulnerability requires that the device is configured as a Gateway (VPN virtual server, ICA Proxy, CVPN, RDP Proxy) OR AAAvirtualserver.

Note, the vulnerability is being actively exploited in the wild.

External links:

https://support.citrix.com/article/CTX584986

About zero-day vulnerabilities

Zero-day vulnerability is an undisclosed vulnerability in software that hackers can exploit to compromise computer programs, gain unauthorized access to sensitive data, penetrate networks, etc. We consider vulnerability a zero-day when there is no solution provided from software vendor and the vulnerability is being actively exploited by malicious actors.

Zero-day candidate is a potential zero-day vulnerability in software which might have been used in targeted attacks, however there is no evidence to support this suggestion.