CVE-2022-24938 in Ember ZNet
Summary
by MITRE • 11/14/2022
A malformed packet causes a stack overflow in the Ember ZNet stack. This causes an assert which leads to a reset, immediately clearing the error.
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Analysis
by VulDB Data Team • 12/18/2022
The vulnerability identified as CVE-2022-24938 represents a critical stack overflow condition within the Ember ZNet stack implementation that affects embedded networking systems. This flaw manifests when the system processes a malformed network packet, triggering an exploitable buffer overflow scenario that fundamentally compromises system stability and operational integrity. The Ember ZNet stack serves as a foundational component for Zigbee-based wireless communication networks, particularly in smart home and industrial automation environments where reliable network operation is paramount for security and functionality.
The technical mechanism behind this vulnerability involves the improper handling of packet data structures within the Ember ZNet protocol implementation. When a specially crafted malformed packet is received by a device running the affected stack, the system's packet parsing routine fails to properly validate input boundaries before copying data into fixed-size stack buffers. This classic buffer overflow condition occurs because the implementation does not enforce adequate bounds checking on incoming packet payloads, allowing maliciously formatted data to overwrite adjacent stack memory regions. The vulnerability specifically targets the stack-based memory allocation pattern where local variables and function call metadata are stored, making it particularly dangerous as it can potentially corrupt program execution flow and control structures.
The operational impact of this vulnerability extends beyond simple system instability, creating a significant security risk for deployed IoT and embedded systems. When the malformed packet is processed, the stack overflow triggers an assertion failure that results in immediate system reset, effectively clearing all error states and preventing any meaningful forensic analysis of the incident. This behavior creates a covert attack vector where malicious actors can repeatedly disrupt network operations without leaving detectable traces, as the system automatically recovers from the assert condition. The reset mechanism prevents any opportunity for security personnel to analyze the overflow condition or extract valuable threat intelligence from the system state, making this vulnerability particularly concerning for network monitoring and incident response capabilities.
The vulnerability aligns with CWE-121 Stack-based Buffer Overflow, which specifically addresses buffer overflows occurring in stack memory regions due to inadequate bounds checking of user-supplied data. From an adversarial perspective, this weakness maps to multiple ATT&CK techniques including T1499.001 for network disruption and T1566.001 for phishing attacks that could be leveraged to deliver the malformed packets. The affected systems typically include various IoT devices, smart home appliances, and industrial automation controllers that utilize Ember's ZNet stack for wireless communication, creating a substantial attack surface across multiple industry sectors. Organizations deploying these systems face potential operational disruptions, data integrity issues, and increased risk of cascading failures in interconnected networks where multiple devices rely on the same wireless protocol stack.
Mitigation strategies for this vulnerability should prioritize immediate firmware updates from manufacturers, as the primary fix involves implementing proper bounds checking in packet parsing routines. Network administrators should also consider implementing ingress filtering rules to prevent malformed packets from reaching vulnerable systems, though this approach may not fully address the issue given the nature of the vulnerability. Additionally, system monitoring should be enhanced to detect unusual reset patterns that could indicate exploitation attempts, while maintaining proper logging capabilities to capture pre-reset system states. The vulnerability underscores the critical importance of robust input validation in embedded systems and highlights the necessity of comprehensive security testing for network protocol implementations in IoT environments.