CVE-2017-7936 in i.MX 50
Summary
by MITRE
A stack-based buffer overflow issue was discovered in NXP i.MX 50, i.MX 53, i.MX 6ULL, i.MX 6UltraLite, i.MX 6SoloLite, i.MX 6Solo, i.MX 6DualLite, i.MX 6SoloX, i.MX 6Dual, i.MX 6Quad, i.MX 6DualPlus, i.MX 6QuadPlus, Vybrid VF3xx, Vybrid VF5xx, and Vybrid VF6xx. When the device is configured in security enabled configuration, SDP could be used to download a small section of code to an unprotected region of memory.
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Analysis
by VulDB Data Team • 01/07/2021
The vulnerability identified as CVE-2017-7936 represents a critical stack-based buffer overflow affecting multiple NXP i.MX processor families including the i.MX 50, i.MX 53, i.MX 6ULL, and various other models in the i.MX 6 and Vybrid series. This flaw exists within the secure digital programming (SDP) functionality that is designed to enable secure firmware updates and code loading operations. The vulnerability specifically manifests when devices operate in security-enabled configurations where the SDP protocol is active and accessible. The issue stems from inadequate bounds checking during memory allocation operations within the processor's boot and initialization routines. When an attacker can leverage SDP to download code to an unprotected memory region, the system's stack becomes vulnerable to overflow conditions that can be exploited to execute arbitrary code with elevated privileges.
The technical implementation of this vulnerability involves the exploitation of memory management weaknesses in the device's secure boot process. The buffer overflow occurs because the system does not properly validate the size of data being written to stack memory locations during SDP operations. This allows an attacker to overwrite adjacent stack memory contents including return addresses and control data structures. The vulnerability is particularly dangerous because it can be triggered through legitimate SDP interfaces that are enabled in security-sensitive configurations, making it accessible to attackers who might gain physical access to the device or who can communicate with it through the SDP protocol. According to CWE classification, this represents a classic stack buffer overflow vulnerability (CWE-121) that falls under the category of memory corruption flaws, which are among the most common and dangerous classes of vulnerabilities in embedded systems.
The operational impact of CVE-2017-7936 extends beyond simple code execution to potentially compromise the entire device security posture. When successfully exploited, the vulnerability can allow attackers to bypass security mechanisms and gain unauthorized access to the device's secure execution environment. This could lead to complete system compromise, firmware modification, or the ability to extract sensitive cryptographic keys and security credentials stored within the device. The affected processors are commonly used in automotive systems, industrial control equipment, and other security-critical applications where such vulnerabilities could have severe consequences. The vulnerability's exploitation requires minimal privileges since it targets the secure boot process itself, which typically operates with high-level security permissions. From an ATT&CK framework perspective, this vulnerability maps to techniques involving privilege escalation and execution of malicious code within secure environments, specifically targeting the boot process and secure firmware loading mechanisms.
Mitigation strategies for CVE-2017-7936 require a multi-layered approach combining firmware updates, configuration hardening, and operational security measures. The primary solution involves applying NXP's official security patches and firmware updates that address the buffer overflow conditions in the SDP implementation. Organizations should disable SDP functionality when it is not required for legitimate operations, particularly in production environments where the risk of exploitation is higher. Physical security controls should be implemented to prevent unauthorized access to devices that might allow exploitation through SDP interfaces. Network segmentation and access controls should limit who can communicate with devices using SDP protocols. Additionally, monitoring systems should be deployed to detect unusual SDP activity patterns that might indicate exploitation attempts. The vulnerability highlights the importance of secure boot implementations and proper memory management in embedded systems, emphasizing that even security-critical features like SDP must be rigorously validated against buffer overflow attacks. Regular security assessments and vulnerability scanning should be conducted to identify and remediate similar issues in other embedded components within the same device ecosystem.