CVE-2019-5055 in N300
Summary
by MITRE
An exploitable denial-of-service vulnerability exists in the Host Access Point Daemon (hostapd) on the NETGEAR N300 (WNR2000v5 with Firmware Version V1.0.0.70) wireless router. A SOAP request sent in an invalid sequence to the <WFAWLANConfig:1#PutMessage> service can cause a null pointer dereference, resulting in the hostapd service crashing. An unauthenticated attacker can send a specially-crafted SOAP request to trigger this vulnerability.
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Analysis
by VulDB Data Team • 12/19/2023
The vulnerability identified as CVE-2019-5055 represents a critical denial-of-service weakness within the Host Access Point Daemon (hostapd) component of NETGEAR N300 wireless routers running firmware version V1.0.0.70. This flaw resides in the router's implementation of the Wireless Future Alliance (WFA) WLAN configuration service, specifically within the SOAP-based interface used for managing wireless network parameters. The issue manifests when an invalid sequence of SOAP requests is sent to the WFAWLANConfig:1#PutMessage service endpoint, creating a condition that leads to a null pointer dereference within the hostapd process. The vulnerability's exploitation requires no authentication credentials, making it particularly dangerous as any remote attacker can trigger the service disruption without prior access to the device. This represents a significant security gap in the router's web service implementation and demonstrates a fundamental flaw in input validation and request handling mechanisms.
The technical exploitation of this vulnerability occurs through a carefully crafted SOAP request that violates the expected sequence or structure of communication with the WFAWLANConfig service. When hostapd processes this malformed request, it attempts to dereference a null pointer during the message processing routine, causing the daemon to crash and terminate unexpectedly. This null pointer dereference falls under the common software vulnerability category classified as CWE-476, which specifically addresses null pointer dereference conditions that can lead to application crashes and service interruptions. The flaw demonstrates poor error handling practices in the SOAP message processing code where the application fails to properly validate incoming request parameters or verify that required pointers are initialized before use. The service crash results in complete loss of wireless functionality for the affected router, effectively rendering the device unable to provide network access to connected clients until manual intervention or device reboot occurs.
The operational impact of CVE-2019-5055 extends beyond simple service disruption to potentially compromise network availability and user productivity in both residential and enterprise environments. For end-users, this vulnerability can result in unexpected network outages during critical operations, while for network administrators managing multiple devices, it presents a significant risk of cascading failures across connected networks. The vulnerability's accessibility from any remote location without authentication makes it particularly attractive to malicious actors who could exploit it for network disruption attacks or as part of broader reconnaissance activities. The issue also aligns with ATT&CK technique T1499.002, which covers network disruption through service availability attacks, demonstrating how this vulnerability could be weaponized in coordinated denial-of-service campaigns. Additionally, the flaw contributes to the broader category of IoT device vulnerabilities where embedded systems lack proper input sanitization and robust error handling mechanisms.
Mitigation strategies for CVE-2019-5055 should focus on immediate firmware updates provided by NETGEAR to address the root cause of the null pointer dereference in the hostapd implementation. Network administrators should implement network segmentation and access controls to limit exposure of affected devices to untrusted networks, while also monitoring for unusual SOAP traffic patterns that might indicate exploitation attempts. The vulnerability highlights the importance of secure coding practices and proper input validation in embedded systems, particularly those handling network service communications. Organizations should also consider implementing intrusion detection systems that can identify and block malformed SOAP requests targeting the affected WFAWLANConfig service. Additionally, the issue underscores the necessity of regular security assessments of network infrastructure devices and the importance of maintaining up-to-date firmware to protect against known vulnerabilities. The vulnerability serves as a reminder of the critical need for robust error handling and input validation in network services, particularly in IoT and embedded systems where service availability is crucial for network operations.