CVE-2021-21772 in lib3mf
Summary
by MITRE • 03/11/2021
A use-after-free vulnerability exists in the NMR::COpcPackageReader::releaseZIP() functionality of 3MF Consortium lib3mf 2.0.0. A specially crafted 3MF file can lead to code execution. An attacker can provide a malicious file to trigger this vulnerability.
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Analysis
by VulDB Data Team • 03/31/2021
The vulnerability CVE-2021-21772 represents a critical use-after-free condition within the 3MF Consortium lib3mf 2.0.0 library, specifically within the NMR::COpcPackageReader::releaseZIP() function. This flaw resides in the handling of 3D manufacturing files that follow the 3D Manufacturing Format standard, which is widely adopted for additive manufacturing processes. The 3MF format, designed to represent 3D manufacturing data including geometry, materials, and process parameters, becomes a vector for exploitation when processed through vulnerable implementations of the lib3mf library.
The technical implementation of this vulnerability stems from improper memory management during the release of ZIP archive resources within the 3MF package reader. When a malformed 3MF file is processed, the library attempts to release memory associated with ZIP decompression operations without proper validation of resource states. This creates a scenario where freed memory locations may be accessed or reused before the application has completed its reference to the memory block, leading to undefined behavior that can be exploited for arbitrary code execution. The vulnerability manifests as a classic use-after-free condition, which is categorized under CWE-416 as "Use After Free" and falls within the broader category of memory safety issues.
The operational impact of this vulnerability extends beyond simple code execution, as it can enable attackers to gain full control over affected systems that process 3MF files. This is particularly concerning in environments where 3MF files are automatically processed, such as 3D printing service providers, design collaboration platforms, or manufacturing automation systems. The attack vector requires only the delivery of a malicious 3MF file, making it highly accessible for exploitation. The vulnerability affects systems that rely on lib3mf 2.0.0 for processing 3D manufacturing data, potentially compromising entire supply chain processes where 3D models are shared and processed across different platforms and organizations.
Mitigation strategies for CVE-2021-21772 primarily focus on immediate remediation through library updates, as the 3MF Consortium has released patched versions of lib3mf that address the memory management issues in the releaseZIP function. Organizations should conduct comprehensive vulnerability assessments to identify all systems and applications that utilize lib3mf 2.0.0, particularly those that process untrusted 3MF files from external sources. Additional defensive measures include implementing strict file validation procedures, deploying sandboxing mechanisms for 3MF file processing, and establishing secure coding practices that prevent similar memory safety issues. From an ATT&CK perspective, this vulnerability maps to T1059.007 for command and scripting interpreter and T1203 for Exploitation for Client Execution, representing the typical attack patterns associated with use-after-free exploits in software libraries.