CVE-2021-38435 in Connext DDS Professional
Summary
by MITRE • 05/05/2022
RTI Connext DDS Professional and Connext DDS Secure Versions 4.2x to 6.1.0 not correctly calculate the size when allocating the buffer, which may result in a buffer overflow.
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Analysis
by VulDB Data Team • 02/05/2025
The vulnerability identified as CVE-2021-38435 affects RTI Connext DDS Professional and Connext DDS Secure versions ranging from 4.2x through 6.1.0. This issue represents a critical buffer management flaw that resides within the data distribution service implementation. The vulnerability stems from improper buffer size calculation during memory allocation processes, creating a scenario where insufficient memory is allocated for data handling operations. This fundamental flaw in the memory management system allows for potential exploitation through carefully crafted data inputs that exceed the allocated buffer boundaries. The affected RTI Connext DDS implementations are widely used in industrial control systems, aerospace applications, and automotive networks where reliable data communication is paramount for system safety and operational integrity.
The technical root cause of this vulnerability manifests as a buffer overflow condition resulting from inadequate input validation and memory allocation calculations. When the DDS service processes incoming data streams, it computes buffer sizes based on certain assumptions about data length and structure that prove incorrect in specific scenarios. This miscalculation leads to scenarios where data exceeding the allocated buffer space is written beyond the intended memory boundaries. The flaw operates at the memory management layer of the DDS implementation, where the system fails to properly account for all potential data expansion factors including padding, alignment requirements, and protocol overhead. This type of vulnerability falls under CWE-129, which specifically addresses insufficient size checks, and can be classified as a memory safety issue within the context of the ATT&CK framework under the technique of memory corruption vulnerabilities.
The operational impact of CVE-2021-38435 extends significantly across industries that rely on RTI Connext DDS for mission-critical communications. In industrial control systems, this vulnerability could potentially allow attackers to execute arbitrary code on affected systems, leading to complete system compromise and potential physical safety hazards. The automotive industry, where DDS is extensively used for vehicle communication networks, faces risks of unauthorized vehicle control or data manipulation that could result in serious safety incidents. Aerospace applications using RTI Connext DDS for flight control and telemetry communications could experience system failures or unauthorized access that threatens mission success and passenger safety. The vulnerability's exploitation potential increases when considering that DDS services often run with elevated privileges and handle sensitive operational data, making the buffer overflow a serious threat to system integrity and availability.
Mitigation strategies for CVE-2021-38435 must address both immediate remediation and long-term architectural improvements. Organizations should immediately upgrade to RTI Connext DDS versions that contain the patched buffer allocation logic, typically versions beyond 6.1.0 where the memory management has been corrected. System administrators should implement network segmentation and access controls to limit exposure of DDS services to untrusted networks. Input validation should be enhanced at all communication boundaries to prevent malformed data from reaching the vulnerable buffer allocation code. Additionally, monitoring systems should be deployed to detect anomalous data patterns that might indicate exploitation attempts. The ATT&CK framework suggests implementing defensive measures such as address space layout randomization and stack canaries to make exploitation more difficult. Organizations should also conduct thorough security assessments of their DDS deployments to identify other potential vulnerabilities in related components and ensure proper configuration management practices are followed.