CVE-2018-4027 in A1 Dashcam
Summary
by MITRE
An exploitable denial-of-service vulnerability exists in the XML_UploadFile Wi-Fi command of the NT9665X Chipset firmware, running on the Anker Roav A1 Dashcam, version RoavA1SWV1.9. A specially crafted packet can cause a semaphore deadlock, which prevents the device from receiving any physical or network inputs. An attacker can send a specially crafted packet to trigger this vulnerability.
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Analysis
by VulDB Data Team • 09/17/2023
The CVE-2018-4027 vulnerability represents a critical denial-of-service flaw within the NT9665X chipset firmware powering the Anker Roav A1 Dashcam device. This vulnerability specifically targets the XML_UploadFile Wi-Fi command implementation, exposing a fundamental weakness in the device's network processing capabilities. The flaw manifests as a semaphore deadlock condition that fundamentally cripples the device's operational integrity by preventing it from processing any subsequent physical or network inputs. The vulnerability's exploitable nature stems from insufficient input validation and improper synchronization mechanisms within the firmware's wireless communication stack, creating a scenario where malicious actors can disrupt device functionality through crafted network packets.
The technical implementation of this vulnerability involves a race condition or improper semaphore handling within the Wi-Fi command processing logic. When the XML_UploadFile command receives a specially crafted packet, the firmware's semaphore management system enters a deadlock state where critical resources become permanently unavailable. This semaphore deadlock prevents the device from maintaining its normal operational flow, effectively rendering the dashcam non-responsive to legitimate network traffic or physical inputs. The vulnerability's design flaw aligns with CWE-362, which catalogs race conditions and synchronization issues in concurrent programming, and represents a classic example of how improper resource management can lead to complete system unavailability. The specific context of this vulnerability within the NT9665X chipset demonstrates how embedded wireless communication processors can contain fundamental flaws that affect device reliability and availability.
The operational impact of CVE-2018-4027 extends beyond simple service disruption to encompass complete device compromise and potential safety implications for users. When a semaphore deadlock occurs, the dashcam becomes completely unresponsive to network commands, rendering features like firmware updates, configuration changes, or remote monitoring impossible. Physical inputs such as button presses or connection events also cease to function, leaving users unable to interact with their device. This vulnerability can be exploited remotely without requiring physical access, making it particularly dangerous for connected devices in automotive environments. The ATT&CK framework categorizes this vulnerability under T1499.004 for Network Denial of Service, as it specifically targets network availability through resource exhaustion or system lockup mechanisms. The device's operational failure creates a security risk where legitimate users cannot access their dashcam functionality, while malicious actors can maintain persistent disruption of service.
Mitigation strategies for CVE-2018-4027 must address both immediate protective measures and long-term firmware improvements. Users should implement network segmentation and firewall rules to prevent unauthorized access to the device's wireless interface, while network administrators should monitor for unusual traffic patterns that might indicate exploitation attempts. The most effective long-term solution involves firmware updates from the vendor that address the semaphore deadlock condition through proper synchronization mechanisms and input validation. Security researchers recommend implementing watchdog timers to detect and recover from deadlock conditions automatically, as well as incorporating proper resource cleanup procedures to prevent resource exhaustion. The vulnerability demonstrates the importance of robust concurrency control in embedded systems and highlights the need for comprehensive security testing of network interfaces in IoT devices. Organizations should also consider implementing network access controls and monitoring solutions to detect and respond to potential exploitation attempts. Device manufacturers should adopt secure coding practices that prevent race conditions and implement proper error handling for network communication protocols to prevent similar vulnerabilities from manifesting in future firmware releases.