CVE-2016-20009 in VxWorks
Summary
by MITRE • 03/12/2021
** UNSUPPORTED WHEN ASSIGNED ** A DNS client stack-based buffer overflow in ipdnsc_decode_name() affects Wind River VxWorks 6.5 through 7. NOTE: This vulnerability only affects products that are no longer supported by the maintainer.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 08/06/2024
This vulnerability represents a critical stack-based buffer overflow within the DNS client implementation of Wind River VxWorks operating systems. The flaw specifically resides in the ipdnsc_decode_name() function which processes DNS name decoding operations. The vulnerability affects VxWorks versions 6.5 through 7, indicating it has been present across multiple generations of this real-time operating system. The buffer overflow occurs when the DNS client processes malformed or specially crafted DNS responses, potentially allowing remote attackers to execute arbitrary code on affected systems. This type of vulnerability falls under CWE-121 Stack-based Buffer Overflow, which is classified as a fundamental memory safety issue where data written to a buffer exceeds the allocated stack space. The vulnerability's impact is particularly concerning in embedded systems environments where VxWorks is commonly deployed, including industrial control systems, automotive applications, and network infrastructure devices.
The technical exploitation of this vulnerability requires an attacker to craft malicious DNS responses that trigger the buffer overflow during name decoding operations. When the ipdnsc_decode_name() function processes these malformed responses, it fails to properly validate input lengths against allocated buffer boundaries, leading to memory corruption that can be leveraged for code execution. This attack vector aligns with ATT&CK technique T1071.004 for Application Layer Protocol: DNS, where attackers manipulate DNS traffic to achieve their objectives. The vulnerability's presence in VxWorks 6.5 through 7 indicates it was likely introduced during the development lifecycle and persisted across versions, making it a legacy issue that affects systems in production environments where upgrading is not feasible. The fact that this vulnerability only affects unsupported products significantly reduces the likelihood of vendor patches being available, leaving affected organizations with limited remediation options.
The operational impact of this vulnerability extends beyond simple code execution to potentially compromise entire embedded systems and industrial control networks. Given that VxWorks is widely used in critical infrastructure applications, a successful exploitation could lead to system crashes, unauthorized access, or complete system compromise. The vulnerability's nature makes it particularly dangerous in environments where system stability and security are paramount, such as power grids, water treatment facilities, and transportation systems. Organizations relying on these unsupported systems face significant risk exposure, as the lack of vendor support means no security updates or patches are available. The vulnerability demonstrates the importance of maintaining proper lifecycle management for embedded operating systems and highlights the risks associated with using unsupported software in production environments. The absence of vendor support also means that security researchers and organizations cannot rely on official channels for vulnerability disclosure or mitigation guidance.
Mitigation strategies for this vulnerability are severely limited due to the unsupported nature of the affected VxWorks versions. Organizations should implement network-level controls such as DNS filtering and monitoring to detect and prevent exploitation attempts. Network segmentation and access controls can help reduce the attack surface by limiting which systems can interact with DNS services. Physical security measures and system hardening practices become crucial for protecting systems that cannot be upgraded. The vulnerability serves as a reminder of the importance of maintaining supported software versions and implementing proper vulnerability management processes. Organizations should conduct comprehensive risk assessments to identify all systems running unsupported VxWorks versions and develop contingency plans for potential exploitation. Due to the lack of official patches, defensive measures should focus on network monitoring and anomaly detection to identify potential exploitation attempts. The vulnerability also underscores the need for organizations to establish clear software lifecycle policies that prevent the deployment of unsupported operating systems in critical environments.