CVE-2018-3898 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. The trans_info call can overwrite a buffer of size 0x104, which is more than enough to overflow the return address from the ssid_dst field.
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Analysis
by VulDB Data Team • 06/04/2023
The vulnerability described in CVE-2018-3898 represents a critical buffer overflow flaw within the Yi Home Camera 27US firmware version 1.8.7.0D, specifically affecting the QR code scanning functionality. This issue stems from inadequate input validation and memory management within the camera's software implementation, creating a pathway for remote code execution through maliciously crafted QR codes. The vulnerability manifests when the device processes a specially designed QR code that triggers a buffer overflow condition, potentially allowing attackers to execute arbitrary code on the affected device. The flaw is particularly concerning as it enables remote exploitation without requiring physical access to the device, making it a significant security risk for users of this particular camera model.
The technical implementation of this vulnerability involves a specific memory corruption scenario where the trans_info function handles QR code data processing. The buffer allocated for ssid_dst field measures 0x104 bytes, which is insufficient to contain the data being written during QR code parsing. This buffer overflow directly impacts the return address stored on the stack, allowing an attacker to overwrite critical execution flow information. The vulnerability is classified as a classic stack-based buffer overflow, which can be exploited to redirect program execution to malicious code locations. This type of vulnerability is commonly categorized under CWE-121 Stack-based Buffer Overflow, representing a well-documented attack vector that has been extensively studied in cybersecurity literature. The attack surface is further expanded by the fact that the vulnerability can be triggered through network-based interactions via QR code scanning, aligning with ATT&CK technique T1189 for exploitation through remote access.
The operational impact of this vulnerability extends beyond simple code execution, as it fundamentally compromises the security posture of the affected devices. Once successfully exploited, attackers gain complete control over the camera's operational capabilities, including access to video feeds, configuration settings, and potentially the ability to use the device as a pivot point for accessing other network resources. The implications are particularly severe for home security systems where these cameras are commonly deployed, as they could be used for unauthorized surveillance or as entry points for broader network compromise. The vulnerability affects a specific firmware version, making it crucial for users to understand their device's firmware status and implement appropriate remediation measures. The device's network connectivity and the fact that QR code scanning is a user-facing feature create multiple potential attack vectors, including social engineering scenarios where users might scan malicious QR codes presented in public or untrusted environments.
Mitigation strategies for CVE-2018-3898 should focus on both immediate firmware updates and operational security measures. The primary recommendation involves updating to the latest firmware version provided by Yi to address the underlying buffer overflow issue. Security researchers and users should also implement network segmentation and monitoring to detect unusual QR code scanning activities that might indicate exploitation attempts. Additional defensive measures include disabling QR code scanning functionality when not required, implementing network access controls, and monitoring for unauthorized device modifications. The vulnerability highlights the importance of input validation and memory safety practices in embedded systems, particularly in IoT devices where security updates may be infrequent or unavailable. Organizations should consider the broader implications of this vulnerability within their security frameworks, as it demonstrates how seemingly benign features like QR code scanning can become attack vectors in poorly implemented software. The incident underscores the necessity of secure coding practices and thorough security testing for IoT devices, particularly those with network connectivity and user interaction capabilities, aligning with industry standards for embedded system security and secure software development practices.