CVE-2020-11580 in Pulse Connect Secure
Summary
by MITRE
An issue was discovered in Pulse Secure Pulse Connect Secure (PCS) through 2020-04-06. The applet in tncc.jar, executed on macOS, Linux, and Solaris clients when a Host Checker policy is enforced, accepts an arbitrary SSL certificate.
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Analysis
by VulDB Data Team • 05/17/2024
The vulnerability identified as CVE-2020-11580 affects Pulse Connect Secure appliances running versions through 2020-04-06, specifically targeting the tncc.jar applet component that operates on multiple operating systems including macOS, Linux, and Solaris. This issue resides within the Host Checker policy enforcement mechanism that is commonly deployed to verify client system compliance before granting network access. The vulnerability represents a critical security flaw that undermines the fundamental trust model of the secure access solution by allowing unauthorized certificate validation.
The technical flaw manifests in the tncc.jar applet's improper handling of SSL certificate validation during the Host Checker process. When a Host Checker policy is enforced, the applet executes on client systems and accepts any SSL certificate without proper validation, effectively bypassing the certificate pinning and trust verification mechanisms that should prevent man-in-the-middle attacks. This behavior creates a dangerous trust relationship where malicious actors can present forged certificates that will be accepted by the client application, potentially enabling credential theft, data interception, or further network exploitation. The vulnerability directly maps to CWE-295 which describes improper certificate validation and can be categorized under ATT&CK technique T1552.001 for credentials from password storage components.
The operational impact of this vulnerability extends beyond simple certificate validation failure, as it fundamentally compromises the security posture of organizations relying on Pulse Connect Secure for remote access. Attackers can exploit this weakness to perform SSL stripping attacks, intercept sensitive communications, or establish persistent access points within the network. The vulnerability affects all supported operating systems where the applet executes, making it particularly dangerous in heterogeneous environments. Organizations using this solution face increased risk of credential compromise, data breaches, and potential lateral movement within their networks, as the Host Checker mechanism that should enforce security compliance becomes ineffective. This vulnerability can be leveraged as a stepping stone for more sophisticated attacks, including privilege escalation and advanced persistent threat operations.
Mitigation strategies should focus on immediate patch application from Pulse Secure, as the vendor has released updates addressing this specific vulnerability. Organizations should also implement network monitoring to detect unusual certificate validation patterns and consider deploying additional security controls such as network segmentation and enhanced logging around the affected appliance. The solution architecture should incorporate certificate transparency monitoring and regular security assessments to identify similar trust relationship issues. Additionally, administrators should review and audit existing Host Checker policies to ensure they are properly configured and monitor for any unauthorized certificate acceptance patterns. Given the nature of the vulnerability, organizations should also consider implementing alternative secure access solutions or additional authentication mechanisms to reduce dependency on potentially compromised components. The remediation process should include comprehensive testing of patched environments to ensure that legitimate certificate validation continues to function properly while eliminating the arbitrary certificate acceptance behavior.