CVE-2021-32994 in OPC UA C++ SDK
Summary
by MITRE • 04/05/2022
Softing OPC UA C++ SDK (Software Development Kit) versions from 5.59 to 5.64 exported library functions don't properly validate received extension objects, which may allow an attacker to crash the software by sending a variety of specially crafted packets to access several unexpected memory locations.
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Analysis
by VulDB Data Team • 04/06/2022
The vulnerability identified as CVE-2021-32994 affects Softing OPC UA C++ SDK versions 5.59 through 5.64, representing a critical memory corruption issue that stems from inadequate input validation within the SDK's library functions. This flaw specifically manifests when the software processes extension objects received from remote endpoints, creating a pathway for malicious actors to exploit memory access violations through crafted network packets. The issue falls under the category of improper input validation as classified by CWE-20, where the system fails to adequately validate data structures received from external sources before processing them.
The technical implementation of this vulnerability involves the SDK's failure to properly validate the structure and content of extension objects during the OPC UA communication process. When the software receives these objects, it does not perform sufficient checks on their internal structure, size, or data types, allowing attackers to construct malicious packets that trigger unexpected memory access patterns. The vulnerability is particularly concerning because it can lead to arbitrary code execution or complete system crashes, as the improperly validated extension objects cause the application to access memory locations that were not intended to be accessed by the legitimate software flow.
From an operational perspective, this vulnerability poses significant risks to industrial control systems and automation environments that rely on Softing OPC UA C++ SDK for communication between devices and applications. The impact extends beyond simple service disruption, as attackers could potentially leverage this vulnerability to gain unauthorized access to critical infrastructure components. The attack surface is particularly wide given that OPC UA is commonly used in manufacturing, energy, and other industrial sectors where system reliability and security are paramount. The vulnerability's exploitation requires minimal network access and can be performed remotely, making it especially dangerous in environments where industrial networks may not have robust network segmentation controls.
The exploitability of this vulnerability aligns with techniques described in the ATT&CK framework under the T1210 - Exploitation of Remote Services tactic, where adversaries leverage vulnerabilities in network services to gain unauthorized access or execute arbitrary code. Organizations using affected SDK versions should implement immediate mitigation strategies including network segmentation to limit access to OPC UA services, deployment of intrusion detection systems to monitor for suspicious packet patterns, and application-level firewalls to filter malformed extension objects. Additionally, the affected software should be updated to versions that have patched this validation flaw, as the vendor has released updated SDK versions that properly validate received extension objects. The vulnerability also highlights the importance of implementing proper input validation controls in industrial communication protocols and adheres to security best practices outlined in NIST SP 800-144 and ISO/IEC 27030 standards for secure communication in industrial environments.