CVE-2018-6692 in Wemo Insight Smart Plug
Summary
by MITRE
Stack-based Buffer Overflow vulnerability in libUPnPHndlr.so in Belkin Wemo Insight Smart Plug allows remote attackers to bypass local security protection via a crafted HTTP post packet.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 05/04/2023
The CVE-2018-6692 vulnerability represents a critical stack-based buffer overflow flaw within the libUPnPHndlr.so library component of Belkin Wemo Insight Smart Plug devices. This vulnerability exists in the Universal Plug and Play handling functionality that governs how these IoT devices communicate and respond to network requests. The flaw specifically manifests when processing crafted HTTP POST packets, enabling remote attackers to exploit the device's communication stack without requiring physical access or local network credentials. The vulnerability stems from inadequate input validation and bounds checking within the UPnP handler module, which fails to properly sanitize incoming data before processing it in a fixed-size stack buffer. This allows malicious actors to overwrite adjacent stack memory locations, potentially leading to arbitrary code execution or system compromise.
The technical implementation of this vulnerability aligns with CWE-121 Stack-based Buffer Overflow, which occurs when a program writes data beyond the bounds of a fixed-length stack buffer. The attack vector leverages the UPnP protocol's HTTP POST handling mechanism where the Belkin Wemo device receives and processes network requests containing malformed data. When an attacker crafts a specific HTTP POST packet with oversized payload data, the vulnerable library function fails to validate the input length against the allocated buffer size, causing a buffer overflow condition. The exploitation process typically involves sending a carefully constructed HTTP request that overflows the stack buffer and potentially overwrites return addresses or other critical stack variables, enabling remote code execution. This vulnerability affects the device's ability to maintain secure communication channels and represents a significant threat to the overall security posture of IoT deployments.
The operational impact of CVE-2018-6692 extends beyond simple remote code execution, as it fundamentally undermines the security model of IoT devices that rely on UPnP for device discovery and control. Compromised Wemo Insight Smart Plugs could be leveraged as entry points for broader network infiltration, potentially allowing attackers to access connected devices, monitor network traffic, or use the compromised device as a pivot point for attacking other systems within the local network. The vulnerability's remote exploitability means that attackers can target these devices from anywhere on the internet without requiring physical access or local network knowledge. Organizations deploying these devices face significant risk exposure, particularly in environments where IoT security is not properly segmented or monitored. The vulnerability also highlights the broader challenges in securing IoT ecosystems, where legacy protocols and insufficient input validation create persistent security weaknesses that can be exploited by threat actors with minimal technical expertise. This type of vulnerability directly impacts the principle of least privilege and can lead to complete device compromise, potentially affecting user privacy and network security.
Mitigation strategies for CVE-2018-6692 should prioritize immediate firmware updates from Belkin, as the vendor would have released patches addressing the specific buffer overflow condition in libUPnPHndlr.so. Network segmentation and firewall rules should be implemented to restrict access to UPnP ports and services, particularly when these devices are not actively needed. Organizations should consider disabling UPnP functionality entirely on affected devices when possible, as this reduces the attack surface and eliminates the vulnerability vector. Security monitoring should include detection of unusual HTTP POST traffic patterns and malformed requests targeting UPnP services. Additionally, implementing network intrusion detection systems can help identify exploitation attempts. The vulnerability underscores the importance of secure coding practices, particularly around input validation and buffer management, as recommended by the OWASP Secure Coding Practices and MITRE ATT&CK framework's defense evasion techniques. Regular security assessments of IoT deployments should include vulnerability scanning for known weaknesses in UPnP implementations and other IoT-specific protocols to prevent similar issues from affecting other networked devices.