CVE-2018-3934 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 set of UDP packets can cause a logic flaw, resulting in an authentication bypass. An attacker can sniff network traffic and send a set of packets to trigger this vulnerability.
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Analysis
by VulDB Data Team • 06/04/2023
The vulnerability identified as CVE-2018-3934 represents a critical security flaw in the Yi Home Camera 27US firmware version 1.8.7.0D, specifically within its firmware update mechanism. This issue falls under the category of authentication bypass vulnerabilities that can lead to full system compromise. The flaw manifests through a logic error in how the camera processes firmware update requests, creating an exploitable condition that allows unauthorized users to bypass the normal authentication procedures required for firmware modifications.
The technical implementation of this vulnerability involves a specific logic flaw that occurs when the camera receives UDP packets during the firmware update process. The camera's firmware update functionality does not properly validate the authenticity of incoming packets or verify the source of update requests, creating a pathway for malicious actors to manipulate the update process. This weakness stems from inadequate input validation and insufficient authentication checks within the network communication protocol handling code.
Network traffic sniffing capabilities enable attackers to observe and capture the specific UDP packet sequences required to exploit this vulnerability. The attack vector relies on the ability to intercept legitimate update traffic and craft malicious packets that exploit the authentication bypass logic flaw. This approach demonstrates a classic example of man-in-the-middle attack patterns where network monitoring and packet manipulation combine to create unauthorized access conditions.
The operational impact of this vulnerability extends beyond simple unauthorized access to encompass complete system compromise and potential data exfiltration. Once authenticated through this bypass mechanism, attackers can install malicious firmware, modify camera settings, access stored video footage, and potentially use the compromised device as a pivot point for further network attacks. The vulnerability affects all devices running the vulnerable firmware version, creating widespread exposure across affected deployments.
This vulnerability aligns with CWE-284, which describes improper access control issues, and demonstrates characteristics consistent with ATT&CK technique T1072, which involves software deployment via network shared folders or similar mechanisms. The flaw represents a critical weakness in the device's security architecture that fails to implement proper access control measures during firmware update operations. The authentication bypass allows attackers to execute arbitrary code on the device, potentially leading to persistent backdoors or complete system takeover.
Mitigation strategies for this vulnerability require immediate firmware updates from the manufacturer to address the specific logic flaw in the firmware update handling code. Network administrators should implement strict firewall rules to restrict UDP traffic to and from the affected devices, particularly blocking unauthorized firmware update communication ports. Additionally, network segmentation and monitoring should be enhanced to detect unusual traffic patterns that might indicate exploitation attempts. The recommended approach involves both immediate patching and network-level controls to prevent exploitation while awaiting official firmware updates from the vendor.