CVE-2021-45342 in LibreCAD
Summary
by MITRE • 01/25/2022
A buffer overflow vulnerability in CDataList of the jwwlib component of LibreCAD 2.2.0-rc3 and older allows an attacker to achieve Remote Code Execution using a crafted JWW document.
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Analysis
by VulDB Data Team • 01/28/2022
The vulnerability identified as CVE-2021-45342 represents a critical buffer overflow flaw within the jwwlib component of LibreCAD version 2.2.0-rc3 and earlier releases. This issue specifically affects the CDataList functionality where improper input validation leads to memory corruption during document processing. The vulnerability exists in the handling of JWW (LibreCAD native format) documents which are used for saving and loading drawing files within the application. When a maliciously crafted JWW document is processed by the vulnerable LibreCAD version, the buffer overflow occurs during parsing operations, potentially allowing attackers to execute arbitrary code on the target system.
The technical nature of this vulnerability aligns with CWE-121, which describes buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent memory locations. The flaw occurs in the memory management routines of the jwwlib library where the application fails to properly validate the size of incoming data before copying it into fixed-size buffers. This allows an attacker to craft a JWW document containing oversized data sequences that exceed the allocated buffer boundaries, leading to stack or heap corruption. The vulnerability is particularly concerning because it enables remote code execution without requiring user interaction beyond opening the malicious document, making it an attractive target for exploitation in targeted attacks.
Operationally, this vulnerability presents a significant risk to users who may unknowingly open malicious JWW files either through phishing campaigns, compromised websites, or malicious file sharing platforms. The remote code execution capability means that attackers can potentially gain full control of affected systems, install backdoors, steal sensitive data, or use the compromised machine as a launch point for further attacks within a network. The impact extends beyond individual users to organizations that rely on LibreCAD for engineering and architectural work, where the opening of a single malicious file could compromise entire design workflows. This vulnerability also demonstrates the importance of input validation in document processing libraries and highlights the potential for supply chain attacks when vulnerable third-party components are integrated into widely-used applications.
Mitigation strategies for CVE-2021-45342 primarily involve immediate upgrading to LibreCAD versions 2.2.0-rc4 or later where the buffer overflow has been patched. Users should also implement defensive measures such as restricting document file types that can be opened, implementing sandboxing techniques, and using automated malware scanning for incoming documents. Network administrators should consider implementing application whitelisting policies that restrict execution of vulnerable versions of LibreCAD and monitor for suspicious document handling activities. The vulnerability also underscores the need for regular security assessments of third-party libraries and components, particularly those handling user-provided data, as highlighted by ATT&CK technique T1203 which covers exploitation for privilege escalation through vulnerable software components. Organizations should also consider implementing security awareness training to prevent users from opening untrusted documents and establish procedures for verifying document integrity before processing.