SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityAnalyzed

CVE-2023-4966

Citrix NetScaler ADC and NetScaler Gateway Buffer Overflow Vulnerability

KEVHIGH 7.5EPSS 100.0%

Does this matter?

Known to be exploited in the wild (CISA KEV, CISA remediation deadline 8 November 2023). Treat as an emergency change: patch or isolate now, then hunt for prior compromise.

Description

Sensitive information disclosure in NetScaler ADC and NetScaler Gateway when configured as a Gateway (VPN virtual server, ICA Proxy, CVPN, RDP Proxy) or AAA  virtual server.

CVSS 3.1
7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
EPSS
100.00% probability · 100th percentile
CISA KEV
Listed 18 October 2023 · due 8 November 2023 · used in ransomware campaigns
Weakness
CWE-119
Affected
citrix/netscaler application delivery controller · citrix/netscaler gateway
Source
secure@citrix.com

CISA notes

Apply mitigations and kill all active and persistent sessions per vendor instructions [https://www.netscaler.com/blog/news/cve-2023-4966-critical-security-update-now-available-for-netscaler-adc-and-netscaler-gateway/] OR discontinue use of the product if mitigations are unavailable. https://www.netscaler.com/blog/news/cve-2023-4966-critical-security-update-now-available-for-netscaler-adc-and-netscaler-gateway/, https://support.citrix.com/article/CTX579459/netscaler-adc-and-netscaler-gateway-security-bulletin-for-cve20234966-and-cve20234967 ; https://nvd.nist.gov/vuln/detail/CVE-2023-4966

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.