CVE-2015-9550 in A850R-V1
Summary
by MITRE • 11/25/2020
An issue was discovered on TOTOLINK A850R-V1 through 1.0.1-B20150707.1612 and F1-V2 through 1.1-B20150708.1646 devices. By sending a specific hel,xasf packet to the WAN interface, it is possible to open the web management interface on the WAN interface.
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Analysis
by VulDB Data Team • 12/10/2020
The vulnerability identified as CVE-2015-9550 represents a critical security flaw affecting TOTOLINK A850R-V1 and F1-V2 wireless routers running specific firmware versions. This issue stems from improper access control mechanisms that fail to adequately validate incoming network traffic on the WAN interface. The vulnerability allows unauthorized remote access to the device's web management interface through a specifically crafted network packet, effectively bypassing normal authentication and authorization protocols that should protect administrative access to network devices.
The technical implementation of this vulnerability involves the transmission of a malformed hel,xasf packet to the WAN interface of affected devices. This particular packet structure triggers a flaw in the router's packet processing logic, causing the device to inadvertently expose its web management interface to external network connections. The vulnerability operates at the network protocol level, specifically targeting the device's handling of incoming packets on the WAN interface, which should normally be restricted to legitimate traffic from the internet service provider. This flaw creates an unintended access path that allows remote attackers to gain administrative privileges without proper authentication.
The operational impact of this vulnerability is severe as it provides attackers with complete administrative control over affected devices. Once exploited, unauthorized users can modify router configurations, change network settings, implement malicious firewall rules, and potentially redirect network traffic to compromise connected devices. The exposure of the web management interface on the WAN interface means that attackers can access the device from anywhere on the internet, eliminating the need for physical access or local network presence. This creates a significant risk for enterprise and home network environments where these devices are deployed, as they become potential entry points for broader network infiltration attempts.
Security professionals should note that this vulnerability aligns with CWE-284, which addresses improper access control issues in network devices. The flaw demonstrates a classic case of insufficient input validation and inadequate network interface protection mechanisms. From an attack framework perspective, this vulnerability maps to ATT&CK technique T1071.001 for application layer protocol usage and T1046 for network service scanning, as attackers can use this vulnerability to identify and exploit exposed management interfaces. Organizations should prioritize immediate firmware updates from TOTOLINK to address this vulnerability, as the affected firmware versions represent a known security risk that can be exploited remotely without requiring specialized tools or significant technical expertise.
The broader implications of this vulnerability extend beyond immediate exploitation, as it demonstrates the importance of network device security hardening and proper interface configuration. Network administrators should implement additional security measures including firewall rules to restrict access to management interfaces, regular firmware updates, and network monitoring to detect unusual traffic patterns that might indicate exploitation attempts. This vulnerability serves as a reminder of the critical need for proper security testing of network device firmware and the implementation of defense-in-depth strategies to protect network infrastructure from unauthorized access.