CVE-2020-11490 in Load Balancer
Summary
by MITRE
Manage::Certificates in Zen Load Balancer 3.10.1 allows remote authenticated admins to execute arbitrary OS commands via shell metacharacters in the index.cgi cert_issuer, cert_division, cert_organization, cert_locality, cert_state, cert_country, or cert_email parameter.
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Analysis
by VulDB Data Team • 05/13/2024
The vulnerability identified as CVE-2020-11490 represents a critical command injection flaw within Zen Load Balancer version 3.10.1's certificate management functionality. This issue resides in the Manage::Certificates module which handles certificate-related operations through the index.cgi interface. The vulnerability specifically affects authenticated administrators who can leverage shell metacharacters within various certificate parameter fields to execute arbitrary operating system commands on the underlying system. The affected parameters include cert_issuer, cert_division, cert_organization, cert_locality, cert_state, cert_country, and cert_email, all of which are processed without proper input sanitization or validation.
This vulnerability maps directly to CWE-77 which defines improper neutralization of special elements used in OS commands, and aligns with ATT&CK technique T1059.001 for command and script injection. The flaw stems from inadequate input validation and sanitization within the certificate management module where user-supplied data flows directly into system command execution contexts without proper escaping or encoding. When an authenticated administrator submits malicious input containing shell metacharacters such as semicolons, ampersands, or backticks within any of the specified certificate fields, the application fails to properly sanitize this input before incorporating it into OS command invocations.
The operational impact of this vulnerability is severe as it provides authenticated attackers with complete system compromise capabilities. An attacker with administrative privileges can execute arbitrary commands with the privileges of the web application process, typically running as root or a high-privilege user. This allows for complete system takeover including data exfiltration, persistence establishment, privilege escalation, and lateral movement within the network. The vulnerability is particularly dangerous because it requires only authentication, making it accessible to any user with administrative access to the Zen Load Balancer interface. The attack surface is further expanded since certificate management is a common administrative function that requires regular updates and modifications.
Mitigation strategies should focus on immediate input validation and sanitization implementation across all certificate parameter fields. Organizations should apply the vendor-provided patch or upgrade to a version that addresses this vulnerability. Input validation should include strict whitelisting of allowed characters and proper escaping of shell metacharacters before any processing occurs. The system should implement proper parameter binding or use of secure APIs that prevent command injection. Network segmentation and principle of least privilege should be enforced to limit the impact of potential exploitation. Security monitoring should be enhanced to detect unusual command execution patterns, and regular security audits should be conducted to identify similar vulnerabilities in other applications. Additionally, implementing web application firewalls and input validation rules can provide additional layers of protection against such injection attacks.