CVE-2020-6149 in OpenUSD
Summary
by MITRE • 11/13/2020
A heap overflow vulnerability exists in Pixar OpenUSD 20.05 when the software parses compressed sections in binary USD files. To trigger this vulnerability, the victim needs to open an attacker-provided malformed file in an instance in USDC file format PATHS section.
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Analysis
by VulDB Data Team • 12/07/2020
The heap overflow vulnerability identified as CVE-2020-6149 represents a critical security flaw within Pixar OpenUSD version 20.05, specifically affecting the parsing of compressed sections within binary USD files. This vulnerability resides in the software's handling of USDC file format PATHS sections, where improper input validation leads to memory corruption. The flaw manifests when the application attempts to process attacker-controlled malformed files that contain specially crafted compressed data structures. The vulnerability is classified under CWE-121 as a heap-based buffer overflow, which occurs when the software writes data beyond the allocated heap memory boundaries. This type of vulnerability falls within the ATT&CK technique T1203 known as "Exploitation for Client Execution" where adversaries leverage software vulnerabilities to execute arbitrary code on target systems.
The technical implementation of this vulnerability stems from insufficient bounds checking during the decompression and parsing process of USDC files. When the application encounters a malformed compressed section within the PATHS section of a binary USD file, it fails to properly validate the size parameters of the compressed data before attempting to decompress and copy it into heap-allocated buffers. The parsing logic does not account for potential integer overflows or maliciously crafted size indicators that could cause the decompression routine to write beyond the intended buffer boundaries. This allows an attacker to control the amount of data written to heap memory, potentially overwriting adjacent memory structures including function pointers, return addresses, or other critical program state information. The vulnerability specifically affects the USDC file format which is designed for efficient binary storage of USD data, making it particularly dangerous as it can be exploited through standard file opening operations without requiring special privileges or complex attack chains.
The operational impact of CVE-2020-6149 extends beyond simple code execution, as successful exploitation can lead to complete system compromise through various attack vectors. An attacker who successfully triggers this vulnerability can potentially achieve remote code execution on systems running affected versions of Pixar OpenUSD, particularly those used in animation studios, visual effects production pipelines, or content creation environments where USD files are routinely processed. The vulnerability is particularly concerning in enterprise environments where USD files are shared across teams, as a single malicious file could compromise multiple systems. The exploitation requires minimal user interaction beyond opening the malicious file, making it suitable for phishing campaigns or supply chain attacks where adversaries distribute compromised USD assets. The heap overflow can result in denial of service conditions, data corruption, or more severe outcomes including privilege escalation depending on the execution environment and system configuration.
Mitigation strategies for CVE-2020-6149 should focus on both immediate defensive measures and long-term architectural improvements. Organizations should immediately update to Pixar OpenUSD versions that have patched this vulnerability, typically those released after the vulnerability disclosure date. The patch implementation addresses the core issue by introducing proper bounds checking and input validation mechanisms during the decompression process of compressed sections. System administrators should implement file validation procedures that scan USD files for potential malformed structures before processing them in production environments. Network-level defenses can include implementing file type restrictions and content inspection for USD files received through email attachments, file transfers, or web downloads. The security controls should also consider implementing sandboxing mechanisms for USD file processing to limit the potential impact of successful exploitation attempts. Additionally, monitoring for unusual file access patterns or system behavior that might indicate exploitation attempts can provide early warning of potential attacks targeting this vulnerability. Organizations should also consider implementing principle of least privilege access controls for USD file processing systems and ensure that the affected software runs with minimal required privileges to reduce the potential impact of any successful exploitation.