CVE-2018-3900 in Home Camera 27US
Summary
by MITRE
An exploitable code execution vulnerability exists in the QR code scanning functionality of Yi Home Camera 27US 1.8.7.0D. A specially crafted QR Code can cause a buffer overflow, resulting in code execution. An attacker can make the camera scan a QR code to trigger this vulnerability. Alternatively, a user could be convinced to display a QR code from the internet to their camera, which could exploit this vulnerability.
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Analysis
by VulDB Data Team • 06/04/2023
The vulnerability identified as CVE-2018-3900 represents a critical code execution flaw within the Yi Home Camera 27US firmware version 1.8.7.0D, specifically within its QR code scanning functionality. This issue falls under the category of buffer overflow vulnerabilities, which are classified as CWE-121 in the Common Weakness Enumeration system. The camera's firmware fails to properly validate the length of data processed during QR code interpretation, creating a pathway for malicious actors to inject and execute arbitrary code on the device. The vulnerability is particularly concerning due to its accessibility through legitimate camera functionality, making it a prime target for social engineering attacks.
The technical implementation of this flaw occurs when the camera's QR code scanner processes specially crafted input data that exceeds the allocated buffer space. This buffer overflow condition allows attackers to overwrite adjacent memory locations, potentially corrupting program execution flow and enabling code injection. The attack vector is facilitated through QR code generation, which can be delivered via physical presentation or remote internet sources, making the exploitation surface broad and accessible. The vulnerability demonstrates poor input validation practices and inadequate memory management within the camera's embedded software system, typical of firmware security weaknesses that are often overlooked during development phases.
The operational impact of this vulnerability extends beyond simple code execution, as it provides attackers with full control over the affected camera device. Once exploited, malicious actors can gain persistent access to the camera's network interface, potentially using it as a pivot point for broader network reconnaissance and lateral movement activities. This aligns with ATT&CK technique T1071.004 for application layer protocol usage and T1046 for network service scanning. The compromised device could serve as a persistent surveillance point, data exfiltration channel, or be used to launch further attacks against local network resources. Additionally, the vulnerability affects user privacy and security, as it allows unauthorized access to camera feeds and potentially sensitive network information.
Mitigation strategies for CVE-2018-3900 require both immediate firmware updates and operational security measures. Device manufacturers should implement proper input validation and bounds checking within the QR code processing module, ensuring all data is strictly validated against predetermined size limits. The firmware should be updated to include stack canaries, address space layout randomization, and other exploit mitigation techniques to prevent successful exploitation. Network administrators should consider isolating affected devices on separate network segments and implementing network monitoring to detect anomalous QR code scanning activities. Users should be educated about the risks of scanning unknown QR codes and the importance of verifying source authenticity before camera interaction with potentially malicious content. The vulnerability also highlights the need for secure coding practices and regular security assessments of embedded systems, particularly those with network connectivity and user interaction capabilities.