CVE-2023-50763 in SIMATIC CP 1542SP-1
Summary
by MITRE • 06/11/2024
A vulnerability has been identified in SIMATIC CP 1542SP-1 (6GK7542-6UX00-0XE0) (All versions < V2.3), SIMATIC CP 1542SP-1 IRC (6GK7542-6VX00-0XE0) (All versions < V2.3), SIMATIC CP 1543SP-1 (6GK7543-6WX00-0XE0) (All versions < V2.3), SIPLUS ET 200SP CP 1542SP-1 IRC TX RAIL (6AG2542-6VX00-4XE0) (All versions < V2.3), SIPLUS ET 200SP CP 1543SP-1 ISEC (6AG1543-6WX00-7XE0) (All versions < V2.3), SIPLUS ET 200SP CP 1543SP-1 ISEC TX RAIL (6AG2543-6WX00-4XE0) (All versions < V2.3), SIPLUS TIM 1531 IRC (6AG1543-1MX00-7XE0) (All versions < V2.4.8), TIM 1531 IRC (6GK7543-1MX00-0XE0) (All versions < V2.4.8). The web server of affected products, if configured to allow the import of PKCS12 containers, could end up in an infinite loop when processing incomplete certificate chains.
This could allow an authenticated remote attacker to create a denial of service condition by importing specially crafted PKCS12 containers.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 06/11/2024
This vulnerability affects several Siemens industrial communication products including SIMATIC CP 1542SP-1, CP 1543SP-1, and related SIPLUS and TIM series devices. The flaw exists in the web server component of these devices when they are configured to accept PKCS12 container imports. The vulnerability manifests as an infinite loop during processing of incomplete certificate chains, representing a critical denial of service condition that can be exploited remotely by authenticated attackers. This issue impacts all versions prior to the specified patches including V2.3 for most models and V2.4.8 for TIM 1531 IRC devices. The affected products are widely deployed in industrial control systems and critical infrastructure environments where reliability and availability are paramount. The vulnerability directly relates to CWE-835, which describes infinite loops or iterations that can lead to system resource exhaustion and denial of service conditions. From an operational perspective, this weakness can severely impact industrial automation and control systems where these communication processors serve as critical network interfaces for device connectivity and data exchange. The attack vector requires authentication to the web interface, which means that an attacker must first obtain valid credentials to exploit this vulnerability. However, in industrial environments where physical access or network monitoring may be limited, the ability to perform a denial of service attack can have cascading effects on operational technology networks and potentially disrupt critical processes.
The technical implementation of this vulnerability stems from insufficient input validation within the certificate processing logic of the web server component. When a PKCS12 container is imported and contains incomplete certificate chains, the processing routine enters an infinite loop rather than properly handling the malformed data. This behavior occurs because the certificate validation code lacks proper boundary checks and termination conditions when encountering certificate chain inconsistencies. The processing logic appears to recursively iterate through certificate references without adequate safeguards against circular or malformed references within the PKCS12 structure. This flaw represents a classic example of improper error handling and input validation that can be exploited to consume system resources and render the affected device non-responsive. The vulnerability aligns with ATT&CK technique T1499.004, which describes network denial of service attacks targeting industrial control systems. The affected devices typically operate in environments where continuous availability is critical, making this vulnerability particularly dangerous for operational technology infrastructure.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromise industrial process control and monitoring systems. When affected devices become unresponsive due to the infinite loop condition, they may fail to process critical communication protocols or maintain network connectivity to other industrial components. This can lead to cascading failures in distributed control systems where multiple devices depend on communication through the affected processors. The vulnerability affects devices that serve as communication gateways between different network segments in industrial environments, making them prime targets for attackers seeking to disrupt operations. The authentication requirement does not prevent exploitation in environments where credentials may be compromised through social engineering, credential theft, or insider threats. Organizations using these devices should consider the potential for extended downtime and the difficulty of recovery from such a condition, especially in environments where physical access to the devices may be limited or require specialized procedures. The vulnerability also highlights the importance of secure configuration practices and the need for regular firmware updates in industrial control systems. The affected products are commonly used in process automation, manufacturing, and critical infrastructure applications where the consequences of service interruption can be severe and may include production losses, safety risks, or regulatory compliance issues. The specific versions affected indicate that this vulnerability has existed for some time and likely affects a significant portion of deployed industrial infrastructure.
Mitigation strategies for this vulnerability should prioritize immediate firmware updates to the latest available versions as provided by Siemens. Organizations should implement strict access controls and network segmentation to limit exposure of these devices to untrusted networks. The web server configuration should be reviewed to disable PKCS12 container import functionality when not required for operational purposes. Network monitoring should be enhanced to detect unusual resource consumption patterns that may indicate exploitation attempts. Security teams should conduct comprehensive vulnerability assessments of their industrial control system environments to identify all affected devices and prioritize remediation efforts. The implementation of network access controls and authentication policies should be strengthened to reduce the attack surface for authenticated exploitation. Regular security awareness training for personnel who have access to these systems should be conducted to prevent credential compromise. Additionally, organizations should consider implementing intrusion detection systems specifically configured to monitor for exploitation attempts targeting industrial control system vulnerabilities. The remediation process should include thorough testing of updated firmware in controlled environments before deployment to production systems to ensure compatibility and prevent unintended operational disruptions. Given the industrial nature of these devices, rollback procedures should be carefully planned and tested to maintain operational continuity during the remediation process.