CVE-2021-33889 in wpantund
Summary
by MITRE • 07/03/2021
OpenThread wpantund through 2021-07-02 has a stack-based Buffer Overflow because of an inconsistency in the integer data type for metric_len.
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Analysis
by VulDB Data Team • 07/09/2021
The vulnerability identified as CVE-2021-33889 affects OpenThread wpantund versions up to 2021-07-02 and represents a critical stack-based buffer overflow condition that stems from an inconsistent integer data type handling for metric_len parameter. This flaw exists within the wireless peripheral network tunneling daemon that facilitates communication between Thread network nodes and external networks. The issue manifests when the system processes network metrics data where the length field is improperly managed, creating a scenario where attacker-controlled input can cause memory corruption through stack buffer overflow conditions.
The technical root cause of this vulnerability lies in the improper handling of integer data types during metric length calculations within the wpantund component. When processing network metrics, the system fails to properly validate or convert the metric_len parameter, leading to a situation where a smaller integer type is used in one context while a larger type is expected in another. This type inconsistency allows an attacker to manipulate the length value in such a way that it exceeds the allocated buffer space on the stack, enabling arbitrary code execution or system crashes. The vulnerability operates at the application layer and requires local or network access to exploit, making it particularly dangerous in environments where untrusted network traffic is processed.
The operational impact of this vulnerability extends beyond simple system instability, as it provides potential attackers with a pathway for privilege escalation and persistent access to affected systems. When exploited successfully, the buffer overflow can lead to complete system compromise, allowing adversaries to execute arbitrary code with the privileges of the wpantund process. This poses significant risks in IoT environments where Thread networks are deployed, as these networks often control critical infrastructure components including smart home devices, industrial sensors, and networked security systems. The vulnerability affects systems running OpenThread wpantund implementations across various embedded platforms and operating systems where Thread networking protocols are utilized.
Mitigation strategies for CVE-2021-33889 should prioritize immediate patching of affected wpantund versions to the latest releases that contain proper integer type handling and bounds checking for metric_len parameters. Organizations should implement network segmentation to limit access to Thread network interfaces and deploy intrusion detection systems to monitor for anomalous network traffic patterns that might indicate exploitation attempts. Additionally, input validation should be strengthened at all network protocol layers to prevent malformed metric data from reaching vulnerable components. This vulnerability aligns with CWE-121 Stack-based Buffer Overflow and represents a technique that could be categorized under ATT&CK tactic TA0002 Execution and TA0004 Privilege Escalation. System administrators should also consider implementing automated patch management solutions and conducting regular vulnerability assessments to identify similar type conversion issues in other network components. The fix typically involves proper type casting and bounds checking mechanisms that ensure metric_len values are validated against expected buffer sizes before processing, preventing the overflow condition from occurring.