CVE-2011-4501 in 6114wg Router
Summary
by MITRE
The UPnP IGD implementation in Edimax EdiLinux on the Edimax BR-6104K with firmware before 3.25, Edimax 6114Wg, Canyon-Tech CN-WF512 with firmware 1.83, Canyon-Tech CN-WF514 with firmware 2.08, Sitecom WL-153 with firmware before 1.39, and Sweex LB000021 with firmware 3.15 allows remote attackers to establish arbitrary port mappings by sending a UPnP AddPortMapping action in a SOAP request to the WAN interface, related to an "external forwarding" vulnerability.
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Analysis
by VulDB Data Team • 08/08/2024
The vulnerability described in CVE-2011-4501 represents a critical security flaw in Universal Plug and Play Internet Gateway Device implementations across multiple network hardware vendors. This issue affects several Edimax and third-party router models including the Edimax BR-6104K, Edimax 6114Wg, Canyon-Tech CN-WF512, Canyon-Tech CN-WF514, Sitecom WL-153, and Sweex LB000021 devices. The vulnerability stems from improper validation of UPnP SOAP requests, specifically within the AddPortMapping action that allows external port forwarding operations. This flaw enables remote attackers to manipulate the router's port mapping configuration without proper authentication, effectively bypassing the device's security controls.
The technical nature of this vulnerability falls under CWE-284, which describes improper access control in software systems. The flaw exists in the UPnP IGD implementation where the device fails to properly authenticate and validate incoming SOAP requests destined for the WAN interface. When attackers send a specially crafted AddPortMapping action request, the router processes this request without sufficient verification of the sender's authorization, allowing arbitrary port mappings to be established. This creates a persistent backdoor that can be exploited to forward traffic to internal network services, effectively circumventing the router's firewall protections.
The operational impact of this vulnerability is severe and multifaceted. Attackers can establish persistent port mappings that allow them to access internal services such as web servers, SSH daemons, or other network applications running on the internal network. This creates a significant risk for organizations where these devices serve as the primary network gateway, as it enables attackers to perform network reconnaissance, establish persistent access, and potentially pivot to other systems within the internal network. The vulnerability is particularly dangerous because it affects multiple vendors and device models, suggesting a widespread implementation flaw that has remained unpatched in numerous firmware versions.
The attack vector for this vulnerability is straightforward yet effective, as it requires only a remote network connection to the device's WAN interface to send a malicious SOAP request. The UPnP service typically operates on port 1900 or uses the device's default HTTP port, making it accessible from external networks if the device is exposed to the internet. This vulnerability aligns with ATT&CK technique T1021.001 for remote services and T1071.004 for application layer protocols, as attackers can leverage UPnP to establish persistent network access. The affected devices represent a significant attack surface for threat actors seeking to establish long-term access to networks, particularly in environments where these devices are deployed without proper network segmentation or firewall rules.
Mitigation strategies for this vulnerability include immediate firmware updates from vendors, network segmentation to isolate affected devices, and disabling UPnP functionality when not required. Organizations should implement network monitoring to detect unauthorized port mapping changes and establish proper firewall rules to restrict access to UPnP ports. The most effective long-term solution involves updating all affected devices to firmware versions that properly validate UPnP requests and implement proper authentication mechanisms. Network administrators should also consider disabling UPnP entirely unless specifically required for legitimate business purposes, as the protocol inherently introduces security risks that are difficult to properly control in enterprise environments.