CVE-2020-9502 in Dahua
Summary
by MITRE
Some Dahua products with Build time before December 2019 have Session ID predictable vulnerabilities. During normal user access, an attacker can use the predicted Session ID to construct a data packet to attack the device.
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Analysis
by VulDB Data Team • 05/14/2020
The vulnerability identified as CVE-2020-9502 affects various Dahua security products that were built prior to December 2019, representing a significant weakness in the authentication mechanisms of these devices. This issue stems from the predictable nature of session identifiers used by the affected systems, which creates a pathway for unauthorized access and potential exploitation. The vulnerability is particularly concerning because it allows attackers to construct malicious data packets using predicted session IDs, effectively bypassing normal authentication procedures. The predictable session ID generation mechanism represents a fundamental flaw in the cryptographic implementation used for session management within these security devices.
The technical flaw manifests in the session ID generation algorithm which fails to incorporate sufficient entropy and randomness required for secure session management. This predictable behavior enables attackers to compute valid session identifiers without requiring legitimate credentials or prior knowledge of active sessions. The vulnerability operates at the application layer and can be exploited through network-based attacks where an attacker can intercept and analyze session creation patterns to predict subsequent session identifiers. This weakness directly violates security best practices outlined in industry standards such as CWE-330, which addresses insufficient entropy in random number generation, and aligns with ATT&CK technique T1566 for phishing and credential harvesting. The predictable session ID generation creates a persistent vulnerability that can be exploited across multiple sessions and potentially across different devices within the same network segment.
The operational impact of this vulnerability extends beyond simple unauthorized access, as it can enable attackers to perform a wide range of malicious activities including but not limited to unauthorized configuration changes, data exfiltration, and potential privilege escalation within the affected systems. Attackers can leverage this vulnerability to maintain persistent access to security devices without detection, potentially compromising the entire security infrastructure. The vulnerability affects the integrity and confidentiality of data processed by these devices, as well as their availability since attackers can disrupt normal operations. Organizations using affected Dahua products face significant risk of security breaches, particularly in environments where these devices are deployed for critical security functions such as video surveillance, access control, and network monitoring.
Mitigation strategies for CVE-2020-9502 should prioritize immediate firmware updates from Dahua to address the predictable session ID generation issue. Organizations must conduct comprehensive inventory assessments to identify all affected devices and implement network segmentation to limit the attack surface. Security monitoring should be enhanced to detect unusual session creation patterns and potential exploitation attempts. The implementation of additional authentication layers such as two-factor authentication and secure session management protocols can provide additional protection. Organizations should also consider implementing network access controls and intrusion detection systems to monitor for suspicious traffic patterns that may indicate exploitation attempts. The vulnerability underscores the importance of proper session management implementation and adherence to security standards such as those outlined in NIST SP 800-63B for authentication and session management practices. Regular security assessments and vulnerability scanning should be conducted to identify similar weaknesses in other networked security devices and ensure comprehensive protection against similar threats.