CVE-2021-40417 in DaVinci Resolve
Summary
by MITRE • 12/22/2021
When parsing a file that is submitted to the DPDecoder service as a job, the service will use the combination of decoding parameters that were submitted with the job along with fields that were parsed for the submitted video by the R3D SDK to calculate the size of a heap buffer. Due to an integer overflow with regards to this calculation, this can result in an undersized heap buffer being allocated. When this heap buffer is written to, a heap-based buffer overflow will occur. This can result in code execution under the context of the application.
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Analysis
by VulDB Data Team • 12/26/2021
The vulnerability identified as CVE-2021-40417 resides within the DPDecoder service component of a multimedia processing system that handles video file submissions. This service operates by receiving job requests that include decoding parameters alongside metadata extracted from video files using the R3D SDK. The core flaw manifests during the buffer allocation phase where the system calculates memory requirements based on a combination of user-provided parameters and parsed video metadata fields. The integer overflow occurs when the mathematical calculation combining these parameters exceeds the maximum representable value for the integer type used in the memory allocation routine, resulting in an unexpectedly small buffer size being allocated in memory.
The technical implementation of this vulnerability follows a classic heap-based buffer overflow pattern that aligns with CWE-190, which specifically addresses integer overflow conditions. When the system attempts to write data to the incorrectly sized heap buffer, the write operations extend beyond the allocated memory boundaries, potentially overwriting adjacent memory structures including function pointers, return addresses, or other critical control data. This memory corruption directly enables arbitrary code execution under the privileges of the DPDecoder service process, representing a significant elevation of privilege threat. The attack vector requires a malicious video file submission that triggers the specific parsing and buffer calculation sequence, making this vulnerability exploitable through file-based attack methods.
The operational impact of CVE-2021-40417 extends beyond simple code execution capabilities as it represents a critical remote code execution vulnerability that could allow attackers to compromise systems running the vulnerable DPDecoder service. The vulnerability affects the integrity and confidentiality of the system since successful exploitation could lead to full system compromise, data exfiltration, or persistent backdoor installation. The service context under which the code executes determines the scope of potential damage, as any privileges granted to the DPDecoder service would be available to the attacker upon successful exploitation. This vulnerability particularly impacts organizations using the affected multimedia processing software in enterprise environments where video processing services are exposed to untrusted inputs.
Mitigation strategies for CVE-2021-40417 should focus on immediate patching of the vulnerable software component to address the integer overflow condition in the buffer calculation logic. System administrators should implement input validation measures that restrict the size parameters and metadata fields processed by the DPDecoder service, particularly limiting the range of values that can contribute to the buffer size calculation. Network segmentation and access controls should be enforced to limit exposure of the vulnerable service to untrusted users or external networks. Additionally, monitoring solutions should be deployed to detect anomalous file processing patterns or unexpected memory allocation behaviors that could indicate exploitation attempts. The ATT&CK framework categorizes this vulnerability under T1203, which covers Exploitation for Client Execution, and T1059, which addresses Command and Scripting Interpreter, as exploitation would likely involve command execution within the compromised system. Organizations should also consider implementing application whitelisting controls to restrict execution of unauthorized code and establish robust incident response procedures for potential exploitation events.