CVE-2020-8247 in ADC
Summary
by MITRE
Citrix ADC and Citrix Gateway 13.0 before 13.0-64.35, Citrix ADC and NetScaler Gateway 12.1 before 12.1-58.15, Citrix ADC 12.1-FIPS before 12.1-55.187, Citrix ADC and NetScaler Gateway 12.0, Citrix ADC and NetScaler Gateway 11.1 before 11.1-65.12, Citrix SD-WAN WANOP 11.2 before 11.2.1a, Citrix SD-WAN WANOP 11.1 before 11.1.2a, Citrix SD-WAN WANOP 11.0 before 11.0.3f, Citrix SD-WAN WANOP 10.2 before 10.2.7b are vulnerable to escalation of privileges on the management interface.
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Analysis
by VulDB Data Team • 09/19/2020
Citrix ADC and Citrix Gateway appliances represent critical components in enterprise network infrastructure, serving as application delivery controllers and secure access gateways that manage traffic flow and authentication for organizations worldwide. These systems handle sensitive network operations including load balancing, SSL offloading, and secure remote access through VPN capabilities. The vulnerability described in CVE-2020-8247 specifically targets the management interface of these appliances, creating a severe security risk that could allow attackers to gain elevated privileges and potentially compromise entire network infrastructures. The affected versions span multiple Citrix product lines including ADC, NetScaler Gateway, and SD-WAN WANOP appliances across several major release versions, indicating a widespread impact across the Citrix product portfolio. This vulnerability represents a critical escalation of privileges flaw that undermines the fundamental security model of these network devices.
The technical flaw underlying CVE-2020-8247 stems from insufficient access controls and privilege validation mechanisms within the management interface of affected Citrix appliances. Attackers can exploit this weakness to escalate their privileges from standard user access to administrative level permissions without proper authentication or authorization checks. The vulnerability likely involves improper input validation or insufficient privilege verification during administrative operations, allowing malicious actors to bypass normal security boundaries. This type of flaw typically falls under CWE-284 which addresses improper access control, and aligns with ATT&CK technique T1068 which covers local privilege escalation. The vulnerability enables attackers to gain root-level access to the management interface, potentially allowing them to modify system configurations, extract sensitive data, or establish persistent access points within the network infrastructure. The exploitation requires minimal privileges initially but provides the attacker with full administrative control over the affected appliances.
The operational impact of this vulnerability extends far beyond simple privilege escalation, as Citrix ADC and Gateway appliances serve as critical network chokepoints that control access to internal resources and applications. When compromised, these appliances can enable attackers to perform man-in-the-middle attacks, intercept and modify network traffic, or establish backdoors for continued access. The vulnerability affects not just individual appliances but entire network segments that rely on these devices for secure access and traffic management. Organizations using these appliances may experience complete loss of network security posture, as attackers can manipulate load balancing configurations, disable security features, or redirect traffic to malicious endpoints. The potential for data exfiltration increases significantly since these appliances often handle sensitive information including user credentials, application data, and network traffic patterns. This vulnerability particularly impacts organizations with distributed workforces relying on remote access capabilities, as it undermines the security of VPN connections that these appliances typically protect.
Mitigation strategies for CVE-2020-8247 require immediate action to patch affected systems and implement additional security controls. Organizations should prioritize updating all affected Citrix ADC and Gateway appliances to the latest available versions, specifically targeting the patches released by Citrix for each affected version line. The vulnerability affects multiple release versions, requiring careful inventory management to identify all impacted devices across the network infrastructure. Network segmentation should be implemented to isolate management interfaces from general network traffic, reducing the attack surface available to potential exploiters. Additional security controls including multi-factor authentication, strict access control policies, and monitoring of management interface activities should be deployed to detect unauthorized access attempts. Security teams should implement network monitoring solutions to detect unusual activity patterns that may indicate exploitation attempts, particularly around management interface access and privilege escalation events. Regular security assessments and vulnerability scanning should be conducted to identify any remaining unpatched systems within the organization's infrastructure. The remediation process should also include reviewing and updating access control policies to ensure that only authorized personnel have access to management interfaces, implementing principle of least privilege for administrative accounts, and establishing robust audit trails for all management activities.