CVE-2018-3890 in Home Camera 27US
Summary
by MITRE
An exploitable code execution vulnerability exists in the firmware update functionality of Yi Home Camera 27US 1.8.7.0D. A specially crafted file can cause a logic flaw and command injection, resulting in code execution. An attacker can insert an SD card to trigger this vulnerability.
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Analysis
by VulDB Data Team • 06/04/2023
The vulnerability identified as CVE-2018-3890 represents a critical security flaw within the firmware update mechanism of Yi Home Camera 27US version 1.8.7.0D. This camera model, widely deployed for home surveillance purposes, contains a logic error that manifests when processing firmware update files, creating a pathway for remote code execution. The flaw specifically resides in how the device handles firmware updates inserted via SD card, making it particularly concerning given the physical accessibility of this update method. The vulnerability stems from inadequate input validation and sanitization within the firmware update handler, allowing attackers to craft malicious files that exploit the device's update process.
The technical exploitation of this vulnerability involves a command injection attack vector that leverages the camera's firmware update functionality. When an attacker inserts a specially crafted SD card containing a malicious firmware update file, the device's processing logic fails to properly validate the file contents, leading to arbitrary command execution with the privileges of the firmware update process. This represents a classic command injection vulnerability that aligns with CWE-77 and follows patterns consistent with ATT&CK technique T1059.007 for command and scripting interpreter. The flaw operates at the firmware level, bypassing traditional network-based security controls and exploiting the device's physical update interface, which typically operates with elevated privileges.
The operational impact of this vulnerability extends beyond simple code execution, as it provides attackers with complete control over the affected camera devices. Once exploited, adversaries can access the device's file system, modify firmware components, install backdoors, and potentially use the compromised camera as a pivot point for accessing the broader home network. The physical nature of the attack vector makes this vulnerability particularly dangerous because it requires no network connectivity or specialized tools beyond an SD card with malicious content. This allows for covert deployment of attacks in environments where network-based detection might be absent, and the attacker can maintain persistent access through the compromised device's storage mechanisms.
Mitigation strategies for CVE-2018-3890 should focus on both immediate and long-term security measures. Immediate actions include disabling firmware update functionality when not actively required, implementing strict physical security controls around camera deployment locations, and regularly monitoring device logs for suspicious activity. Organizations should also consider firmware version updates from the vendor if available, though the specific nature of this vulnerability suggests that the firmware update mechanism itself is compromised. Network segmentation and monitoring of SD card insertion events can provide additional detection capabilities, while regular security assessments of IoT devices should include physical attack surface evaluation. The vulnerability highlights the importance of secure firmware update mechanisms and proper input validation, as outlined in industry standards such as NIST SP 800-148 for secure device lifecycle management and ISO/IEC 27030 for security in IoT environments.