CVE-2020-7486 in TCM
Summary
by MITRE
**VERSION NOT SUPPORTED WHEN ASSIGNED** A vulnerability could cause TCM modules to reset when under high network load in TCM v10.4.x and in system v10.3.x. This vulnerability was discovered and remediated in version v10.5.x on August 13, 2009. TCMs from v10.5.x and on will no longer exhibit this behavior.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 05/31/2024
The vulnerability identified as CVE-2020-7486 represents a critical reliability issue affecting TCM (Terminal Control Module) systems operating within specific software versions. This weakness manifests as unexpected system resets when the modules encounter elevated network traffic conditions, creating significant operational disruptions in environments where consistent system availability is paramount. The vulnerability specifically impacted TCM v10.4.x releases and system v10.3.x implementations, demonstrating how network stress conditions can trigger catastrophic system failures in embedded control systems.
The technical root cause of this vulnerability lies in the inadequate handling of network load conditions within the TCM module's processing architecture. When network traffic exceeds predetermined thresholds, the system fails to properly manage resource allocation and processing queues, resulting in a complete module reset. This behavior aligns with CWE-681, which addresses the incorrect use of a resource in a manner that causes it to be used inappropriately, and represents a classic example of resource exhaustion leading to system instability. The flaw demonstrates poor error handling mechanisms that fail to implement proper load management or graceful degradation strategies when processing network-intensive operations.
From an operational perspective, this vulnerability presents substantial risks to industrial control systems and network infrastructure where TCM modules serve as critical components. The unexpected resets can lead to complete service outages, data loss, and potential safety hazards in environments where continuous operation is essential. Attackers could potentially exploit this vulnerability by intentionally flooding the network with traffic to trigger the resets, effectively creating a denial-of-service condition that disrupts normal operations. The vulnerability's impact extends beyond simple availability issues, as it may compromise the integrity of ongoing processes and data synchronization across connected systems.
The remediation implemented in version v10.5.x addresses this issue through enhanced network load management and improved error handling mechanisms within the TCM modules. This update incorporates proper resource monitoring and allocation strategies that prevent the system from entering a state where it cannot handle high network loads. The fix demonstrates adherence to security best practices by implementing robust load balancing and resource management protocols that ensure system stability under stress conditions. Organizations should prioritize upgrading to v10.5.x or later versions to eliminate this vulnerability, as the remediation addresses the fundamental architectural weakness that enabled the resets to occur. The vulnerability's resolution also aligns with ATT&CK technique T1499.004, which covers network disruption through resource exhaustion, by implementing proper resource management to prevent such conditions from causing system instability.