CVE-2020-3929 in Door Access Control
Summary
by MITRE
GeoVision Door Access Control device family employs shared cryptographic private keys for SSH and HTTPS. Attackers may conduct MITM attack with the derived keys and plaintext recover of encrypted messages.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 10/24/2020
The vulnerability identified as CVE-2020-3929 affects the GeoVision Door Access Control device family, representing a critical weakness in the cryptographic implementation of these security devices. These devices are designed to control physical access to facilities and typically rely on secure communication protocols to maintain their integrity and prevent unauthorized access. The flaw lies in the improper implementation of cryptographic key management where the same private key is shared between SSH and HTTPS protocols, creating a fundamental security weakness that undermines the entire communication security model.
This cryptographic misconfiguration creates a severe attack vector that allows adversaries to perform man-in-the-middle attacks with significant operational impact. The shared private key compromise enables attackers to decrypt communications between the access control devices and authorized users, potentially allowing them to recover plaintext messages that were previously encrypted. This vulnerability directly violates the principle of key separation and isolation that is fundamental to secure cryptographic systems, as outlined in the CWE-327 weakness category for use of weak encryption algorithms and CWE-326 for inadequate encryption strength. The attack surface expands significantly because compromising a single key provides access to multiple communication channels simultaneously.
The operational impact of this vulnerability extends beyond simple data interception to potentially enable full system compromise and unauthorized physical access control. An attacker who successfully exploits this weakness could gain complete control over the door access systems, allowing them to open and close access points at will, potentially creating backdoors into secured facilities. This represents a critical failure in the defense-in-depth strategy of physical security systems, where the compromise of one security layer (network communication) can lead to complete physical access control failure. The vulnerability also aligns with ATT&CK technique T1046 for network service scanning and T1566 for credential harvesting, as attackers could use the compromised communications to gather additional system information and credentials.
Mitigation strategies for CVE-2020-3929 require immediate implementation of proper cryptographic key management practices. Organizations must ensure that separate, unique cryptographic keys are used for each communication protocol, with keys generated using strong random number generators and appropriate key lengths. The devices should be updated with firmware patches that implement proper key separation and secure key management practices. Network segmentation and monitoring should be implemented to detect anomalous communication patterns that might indicate exploitation attempts. Additionally, security assessments should include cryptographic vulnerability scanning to identify similar key management weaknesses in other networked security devices. The remediation process should also include regular key rotation policies and secure key storage mechanisms to prevent future occurrences of this type of vulnerability.