External risk intelligence

Citrix ADC and Gateway Information Disclosure

CVE advisoryKnown Exploit

CVE-2020-8196

This vulnerability affects Citrix ADC and Citrix Gateway, which are edge networking appliances designed to be deployed as internet-facing gateways, VPN entry points, and load balancers. These products are intended for public-facing use in normal enterprise operations to manage and secure network traffic, placing them directly on the internet edge.

Authentication Bypass

Citrix Application Delivery Controller Firmware

10.5 to before 10.5-70.1811.1 to before 11.1-64.1412.0 to before 12.0-63.2112.1 to before 12.1-57.1813.0 to before 13.0-58.3010.2 to before 10.2.711.0 to before 11.0.3d11.1 to before...

Halo Surface Signal: 5 out of 5 — more likely to be public-facing.

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

Citrix Application Delivery Controller and Citrix Gateway are vulnerable due to improper access controls. This flaw allows low-privileged users to access limited information that should not be disclosed. The primary business impact is the potential exposure of sensitive data to unauthorized individuals.

Vulnerable Citrix networking products
Improper access control flaw
Limited information disclosure

Attack Path

How an attacker could exploit the issue

This vulnerability impacts organizations using specific versions of Citrix ADC, Citrix Gateway, and Citrix SD-WAN WANOP appliances. Attackers with limited privileges can exploit this weakness to gain unauthorized access to sensitive information. This exposure could lead to a broader compromise of an organization's data and systems, increasing the overall business risk.

External network access required.
Attacker gains low-privileged access.
Limited information disclosure results.

Live Threat

Current exploitation, exposure, and threat context

This vulnerability allows limited information disclosure to low-privileged users. Attackers with a low skill level could exploit this issue. The potential for unauthorized access to sensitive information presents a significant business risk.

Likely attacker skill: Low
Required access: Limited privileges
Business risk: Significant

Operational Fix

Recommended remediation, mitigation, and detection steps

Organizations utilizing Citrix ADC, Citrix Gateway, or SD-WAN WANOP appliances face a potential risk of limited information disclosure to low-privileged users. This vulnerability, if exploited, could allow attackers to access sensitive data. Immediate attention to identifying and mitigating this risk is advised.

Identify exposed Citrix appliances.
Reduce exposure or isolate affected systems.
Apply vendor fixes, verify, and monitor.

Supplementary metadata

CVSS vector

Validate whether this threat affects your internet-facing exposure.

Halo Threat Intelligence helps prioritize remediation with Halo Surface Signal and H/A/L/O context. Start exposure validation with a free external attack surface trial.

Free EASM Trial See How Signal Works

Frequently asked questions

What are Citrix ADC and Citrix Gateway and what is their purpose in network management?

Citrix ADC (formerly NetScaler ADC) and Citrix Gateway are networking appliances used for managing, securing, and optimizing application and data delivery. They function as secure gateways, enabling users to access internal resources from any location, often utilized for VPN access and load balancing.

What type of weakness does CVE-2020-8196 represent, and which CWE applies?

CVE-2020-8196 is an improper access control vulnerability, classified under CWE-284. This weakness means the software did not properly enforce restrictions, allowing a user with minimal privileges to access information they should not be able to see.

How can an attacker exploit CVE-2020-8196 without network segmentation or significant privileges?

The vulnerability involves improper access control, allowing a low-privileged user to disclose limited information. The attack vector is the network (AV:N), requiring only low privileges (PR:L) with no user interaction (UI:N) and without changing security scope (S:U).

What is the relevance of CVE-2020-8196, as indicated by Halo Surface Signal?

Halo Surface Signal indicates this vulnerability is 'Very likely' to be relevant because it affects internet-facing appliances like Citrix ADC and Citrix Gateway, which are commonly deployed as gateways and VPN entry points on the network edge.

What are the recommended practical steps for organizations to address the CVE-2020-8196 vulnerability?

Organizations should identify any exposed Citrix appliances, reduce their exposure, or isolate affected systems. Applying vendor-provided fixes, verifying their implementation, and continuous monitoring are crucial steps to mitigate this risk.

References

support.citrix.com/article/CTX276688

Written by Nicholas Merritt

Nicholas Merritt is VP of Security Solutions at Halo Security. With more than 25 years across application security, vulnerability prioritization, and offensive security, he helps teams translate threat data into practical exposure validation and remediation focus. He authors Halo Threat Intelligence CVE advisories using Halo Surface Signal and H/A/L/O context to prioritize internet-facing risk.