CVE-2021-38363 in ONOS
Summary
by MITRE • 04/20/2023
An issue was discovered in ONOS 2.5.1. In IntentManager, the install-requested intent (which causes an exception) remains in pendingMap (in memory) forever. Deletion is possible neither by a user nor by the intermittent Intent Cleanup process.
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Analysis
by VulDB Data Team • 05/14/2023
The vulnerability identified as CVE-2021-38363 represents a critical memory management flaw within the ONOS 2.5.1 network operating system platform. This issue specifically affects the IntentManager component which is responsible for handling network intents and their lifecycle management. The problem manifests when an install-requested intent fails to complete successfully, resulting in an exception being thrown during the installation process. Despite the failure, the system does not properly remove this malformed intent from the pendingMap data structure, which exists in volatile memory storage. This represents a fundamental failure in the intent cleanup mechanism that was designed to maintain system stability and resource utilization efficiency.
The technical nature of this vulnerability stems from improper exception handling and memory management within the IntentManager's internal state tracking mechanisms. When an intent installation fails, the system should automatically transition the intent to a failed state and remove it from active memory management structures. However, the current implementation fails to execute this cleanup routine, causing the failed intent to persist indefinitely in the pendingMap. This memory leak occurs at the application level within the ONOS framework's intent management subsystem, specifically affecting the in-memory data structures used to track pending network intents. The vulnerability is classified as a memory leak or resource leak according to CWE-404, which deals with improper resource management and the failure to release resources properly.
The operational impact of this vulnerability is significant for network operators relying on ONOS 2.5.1 for their software-defined networking operations. As failed intents accumulate in memory without proper cleanup, the system experiences gradual degradation in performance and resource utilization. The memory consumption increases continuously over time, potentially leading to system instability, application crashes, or complete service outages. Network administrators may not immediately notice the issue as it develops gradually, making it particularly dangerous for production environments where continuous operation is critical. The persistence of these failed intents can also interfere with legitimate intent processing, as the system may become overwhelmed with stale entries that consume memory resources that should be available for active network operations.
The vulnerability affects the ATT&CK framework's T1490 technique related to "Inhibit System Recovery" through memory exhaustion and resource depletion attacks. This issue can be exploited to create a denial-of-service condition by allowing attackers to repeatedly submit failing intents, causing the system to consume all available memory resources. Additionally, this vulnerability aligns with T1566 technique for "Phishing with Social Engineering" as it can be triggered through legitimate network operations that generate intent failures, making detection more difficult. The lack of user-initiated deletion capability and the failure of the automatic cleanup process creates a persistent state that can be maintained indefinitely, representing a failure in the system's self-healing capabilities. Organizations should implement monitoring solutions to detect memory usage patterns and establish automated alerting when memory consumption exceeds normal thresholds, as this indicates the presence of the memory leak.
Mitigation strategies for CVE-2021-38363 should include immediate upgrade to a patched version of ONOS that addresses the intent cleanup mechanism. System administrators should implement regular monitoring of memory usage patterns and establish automated alerts for unusual memory consumption increases. The current workaround involves manual intervention by restarting the ONOS service to clear the pendingMap, though this is not a sustainable long-term solution. Organizations should also implement network intent validation mechanisms to reduce the likelihood of malformed intents reaching the problematic state. The fix should ensure proper exception handling that automatically transitions failed intents to a terminated state and removes them from the pendingMap, implementing the correct memory management patterns as specified in industry best practices for software-defined networking platforms. Security teams should also consider implementing network segmentation and access controls to limit the exposure of vulnerable ONOS instances to potential abuse.