CVE-2018-16602 in Amazon Web Services FreeRTOS
Summary
by MITRE
An issue was discovered in Amazon Web Services (AWS) FreeRTOS through 1.3.1, FreeRTOS up to V10.0.1 (with FreeRTOS+TCP), and WITTENSTEIN WHIS Connect middleware TCP/IP component. Out of bounds memory access during parsing of DHCP responses in prvProcessDHCPReplies can be used for information disclosure.
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Analysis
by VulDB Data Team • 04/18/2020
The vulnerability identified as CVE-2018-16602 represents a critical memory safety issue affecting multiple embedded networking components including AWS FreeRTOS versions through 1.3.1, FreeRTOS up to V10.0.1 with FreeRTOS+TCP, and the WITTENSTEIN WHIS Connect middleware. This flaw manifests during the processing of DHCP responses within the prvProcessDHCPReplies function, where improper bounds checking allows for out-of-bounds memory access. The vulnerability stems from insufficient validation of DHCP response packet structures, particularly when handling variable-length options fields that may exceed expected buffer boundaries. The root cause aligns with CWE-129, which specifically addresses insufficient bounds checking in software systems, and more broadly with CWE-787, concerning out-of-bounds write operations that can lead to information disclosure and potential system compromise. The issue is particularly concerning in embedded environments where memory corruption can lead to system instability or complete device failure.
The operational impact of this vulnerability extends beyond simple information disclosure, as the out-of-bounds memory access can potentially reveal sensitive data from adjacent memory regions including cryptographic keys, network credentials, or system configuration details. Attackers exploiting this vulnerability could gain unauthorized access to confidential information stored in memory, potentially enabling further exploitation through techniques such as information leakage that could aid in bypassing security controls or conducting more sophisticated attacks. The vulnerability affects networked embedded devices that rely on DHCP for IP address assignment, making it particularly dangerous in IoT deployments where such devices may be deployed in sensitive environments or critical infrastructure. The attack surface is broad given the widespread use of these networking components across various industrial and consumer devices, creating potential for widespread impact across multiple sectors including automotive, healthcare, and industrial control systems.
Mitigation strategies for CVE-2018-16602 should prioritize immediate patching of affected systems, with vendors releasing updated versions of FreeRTOS and related middleware components that include proper bounds checking mechanisms. Organizations should implement network segmentation and monitoring to detect anomalous DHCP traffic patterns that might indicate exploitation attempts. The fix should incorporate defensive programming practices such as validating DHCP option lengths before processing, implementing proper buffer management, and adding bounds checking routines that prevent memory access beyond allocated boundaries. Security teams should also consider implementing runtime protections including memory protection units, address space layout randomization, and stack canaries to mitigate potential exploitation scenarios. The vulnerability highlights the importance of adhering to security standards such as those outlined in the MITRE ATT&CK framework, particularly in the context of privilege escalation and information gathering techniques that attackers might employ when exploiting memory safety vulnerabilities in embedded systems. Organizations should also conduct thorough vulnerability assessments of their embedded device fleets to identify other potential memory safety issues that could be exploited in similar fashion, ensuring comprehensive security coverage across all networked embedded components.