CVE-2018-3892 in Home Camera 27US
Summary
by MITRE
An exploitable firmware downgrade vulnerability exists in the time syncing functionality of Yi Home Camera 27US 1.8.7.0D. A specially crafted packet can cause a buffer overflow, resulting in code execution. An attacker can intercept and alter network traffic to trigger this vulnerability.
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Analysis
by VulDB Data Team • 06/04/2023
The vulnerability identified as CVE-2018-3892 represents a critical firmware downgrade flaw in the Yi Home Camera 27US model running firmware version 1.8.7.0D. This issue resides within the time synchronization functionality of the device, which is typically used to maintain proper system time across networked devices. The flaw enables an attacker to manipulate the camera's firmware update process through malicious network traffic interception, creating a significant security risk for users who rely on these devices for surveillance purposes.
The technical implementation of this vulnerability involves a buffer overflow condition that occurs when the camera processes specially crafted network packets designed to manipulate the time synchronization protocol. When the device receives these malformed packets, the insufficient input validation and bounds checking in the time syncing module allows an attacker to overflow a fixed-size buffer, potentially leading to arbitrary code execution within the device's firmware environment. This buffer overflow vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent memory locations and potentially execute malicious code.
The operational impact of this vulnerability extends beyond simple code execution, as it enables attackers to perform complete firmware downgrades of the affected cameras. This capability allows adversaries to install malicious firmware versions that could provide persistent backdoors, disable security features, or completely compromise the device's functionality. The attack requires only network interception capabilities, making it particularly dangerous as it can be executed remotely without physical access to the device. This aligns with ATT&CK technique T1059.007 for command and scripting interpreter, where attackers can execute code through firmware manipulation.
The exploitation of this vulnerability demonstrates a fundamental flaw in the device's security architecture, particularly in how it handles firmware update processes and network communication protocols. The time synchronization functionality, which should be a simple and secure process, becomes a vector for privilege escalation and persistent access. Network traffic interception can be achieved through various means including man-in-the-middle attacks on unencrypted connections or by compromising network infrastructure. This vulnerability essentially allows attackers to downgrade the camera to a less secure firmware version, potentially removing security patches or introducing malicious code that persists across device reboots.
Mitigation strategies for this vulnerability should include immediate firmware updates from the manufacturer, network segmentation to prevent unauthorized access to camera communication channels, and implementation of encrypted communication protocols where possible. Network administrators should also consider monitoring for unusual time synchronization patterns and implement intrusion detection systems that can identify malformed packets targeting this specific vulnerability. The device should be configured to use secure communication protocols and authentication mechanisms to prevent unauthorized firmware modifications. Organizations should also establish procedures for monitoring and managing firmware versions across all networked devices to prevent exploitation of similar vulnerabilities in other equipment.