CVE-2021-43390 in Drawings SDK
Summary
by MITRE • 11/15/2021
An Out-of-Bounds Write vulnerability exists when reading a DGN file using Open Design Alliance Drawings SDK before 2022.11. The specific issue exists within the parsing of DGN files. Crafted data in a DGN file and lack of proper validation of input data can trigger a write operation past the end of an allocated buffer. An attacker can leverage this vulnerability to execute code in the context of the current process.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 11/16/2021
The vulnerability CVE-2021-43390 represents a critical out-of-bounds write flaw within the Open Design Alliance Drawings SDK, specifically affecting versions prior to 2022.11. This issue manifests during the parsing of DGN (Design Graphics Network) files, which are widely used in computer-aided design and engineering applications. The flaw stems from insufficient input validation mechanisms that fail to properly sanitize or verify the structure and content of DGN file data before processing. When a maliciously crafted DGN file is processed by the vulnerable SDK, the parsing routine attempts to write data beyond the boundaries of allocated memory buffers, creating a condition that can be exploited by attackers to gain unauthorized code execution privileges.
The technical exploitation of this vulnerability occurs through careful manipulation of DGN file structures to trigger buffer overflow conditions during the parsing phase. The flaw operates at the intersection of improper input validation and memory management errors, creating a pathway for arbitrary code execution within the context of the current process. This type of vulnerability aligns with CWE-787, which specifically addresses out-of-bounds write conditions that can result in memory corruption and potential privilege escalation. The attack vector is particularly concerning because it leverages legitimate file processing functionality, making it difficult to detect through traditional security monitoring approaches. The vulnerability demonstrates a classic buffer overflow pattern where crafted input data bypasses normal validation checks and causes memory corruption that can be leveraged for code execution.
The operational impact of this vulnerability extends beyond simple code execution, as it can enable attackers to gain persistent access to systems running vulnerable applications. When exploited successfully, the vulnerability allows attackers to execute malicious code with the privileges of the affected process, potentially leading to complete system compromise. This risk is amplified in environments where the Drawings SDK is used to process untrusted DGN files from external sources, such as in design collaboration platforms or document management systems. The vulnerability affects applications that rely on Open Design Alliance SDK for DGN file processing, including CAD software, engineering design platforms, and document viewing applications. Security professionals should consider this vulnerability in the context of ATT&CK technique T1059, which covers command and scripting interpreter usage, as the successful exploitation could enable attackers to establish persistent command execution capabilities.
Mitigation strategies for CVE-2021-43390 primarily focus on immediate version updates to Open Design Alliance Drawings SDK 2022.11 or later, which contain fixed parsing routines with proper input validation. Organizations should also implement defensive measures such as input sanitization for DGN files, restricted file access controls, and network segmentation to limit potential attack surfaces. Additionally, deploying intrusion detection systems that monitor for anomalous file processing activities and implementing application whitelisting policies can provide additional layers of protection. Security teams should conduct comprehensive vulnerability assessments to identify all systems utilizing the affected SDK and establish monitoring procedures for suspicious file processing activities. The vulnerability highlights the importance of proper input validation in file parsing libraries and underscores the need for regular security updates in third-party software components used in enterprise environments.