CVE-2016-2072 in Netscaler Application Delivery Controller
Summary
by MITRE
The Administrative Web Interface in Citrix NetScaler Application Delivery Controller (ADC) and NetScaler Gateway 11.x before 11.0 Build 64.34, 10.5 before 10.5 Build 59.13, 10.5.e before Build 59.1305.e, and 10.1 allows remote attackers to conduct clickjacking attacks via unspecified vectors.
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Analysis
by VulDB Data Team • 07/08/2022
The vulnerability identified as CVE-2016-2072 represents a critical security flaw in Citrix NetScaler Application Delivery Controller and NetScaler Gateway products across multiple versions. This issue specifically affects the administrative web interface component that administrators use to configure and manage the network infrastructure. The vulnerability enables remote attackers to execute clickjacking attacks, which exploit the trust relationship between a user's browser and the targeted web application. Clickjacking occurs when an attacker tricks a user into clicking on elements that appear to be part of a legitimate interface but actually perform malicious actions in the background. The affected versions include Citrix NetScaler ADC and Gateway 11.x before 11.0 Build 64.34, 10.5 before 10.5 Build 59.13, 10.5.e before Build 59.1305.e, and 10.1, indicating this vulnerability spans across several major release lines of the Citrix product suite. This widespread impact suggests the flaw was present in core architectural components that remained consistent across different versions, making it particularly concerning for organizations with diverse Citrix deployments.
The technical nature of this vulnerability stems from the lack of proper clickjacking protection mechanisms within the administrative web interface. When users access the Citrix NetScaler administrative console, they are exposed to potential manipulation through malicious web pages that overlay transparent or semi-transparent elements on top of legitimate interface components. This allows attackers to capture user interactions intended for the legitimate administration interface and redirect them to malicious actions without the user's knowledge or consent. The unspecified vectors mentioned in the description suggest that the vulnerability could be exploited through various attack methods including framing techniques, CSS positioning manipulations, or JavaScript-based approaches that leverage the browser's lack of proper security controls. The flaw essentially undermines the security model of the administrative interface by failing to implement necessary protections such as X-Frame-Options headers or similar frame-busting mechanisms that would prevent the interface from being embedded within other web pages.
The operational impact of CVE-2016-2072 extends far beyond simple user inconvenience, as it provides attackers with a potential pathway to gain unauthorized administrative access to critical network infrastructure. Successful exploitation could enable attackers to modify configuration settings, add or remove users, alter security policies, and potentially compromise the entire network delivery infrastructure managed by the affected Citrix appliances. Organizations relying on Citrix NetScaler for application delivery and gateway services face significant risk, as this vulnerability could be leveraged to establish persistent access points within their network environments. The administrative interface typically contains sensitive configuration data and control mechanisms that, if compromised, could lead to service disruption, data breaches, or unauthorized network access. The remote nature of the attack means that exploitation does not require physical access to the network or direct network connection to the affected appliances, making it particularly dangerous in environments where network segmentation may not be sufficient to prevent lateral movement.
Organizations affected by this vulnerability should prioritize immediate remediation through official Citrix security patches and updates. The recommended mitigation strategy involves upgrading to the latest supported versions of Citrix NetScaler ADC and Gateway that contain fixes for the clickjacking vulnerability. Security administrators should also implement additional protective measures such as deploying web application firewalls, implementing proper HTTP security headers, and monitoring for suspicious administrative access patterns. Network segmentation and access control policies should be reviewed to limit exposure of administrative interfaces to only necessary personnel and systems. The vulnerability aligns with CWE-1021, which specifically addresses improper restriction of rendering of components, and maps to ATT&CK technique T1071.004 for application layer protocol: web protocols, as it involves manipulation of web-based administrative interfaces. Organizations should also consider implementing security awareness training to help users recognize and avoid potential clickjacking attacks that might attempt to exploit similar vulnerabilities in other systems. Regular security assessments and vulnerability scanning should be conducted to identify any remaining instances of the vulnerable software within the organization's infrastructure.