CVE-2015-9551 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. There is Remote Code Execution in the management interface via the formSysCmd sysCmd parameter.
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Analysis
by VulDB Data Team • 12/10/2020
The vulnerability identified as CVE-2015-9551 represents a critical remote code execution flaw affecting TOTOLINK A850R-V1 and F1-V2 wireless routers. This issue resides within the web-based management interface of these devices, specifically through improper input validation of the formSysCmd parameter. The vulnerability allows attackers to execute arbitrary commands on the affected devices without requiring authentication, making it particularly dangerous for network security. The affected firmware versions span from A850R-V1 through 1.0.1-B20150707.1612 to F1-V2 through 1.1-B20150708.1646, indicating a widespread issue across multiple device models and firmware iterations.
The technical flaw stems from inadequate sanitization of user-supplied input within the sysCmd parameter of the formSysCmd function. When administrators or attackers submit commands through this parameter, the system fails to properly validate or escape the input before executing it within the system shell. This classic command injection vulnerability enables an attacker to execute any command that the device's operating system would normally permit. The vulnerability is categorized under CWE-77 as Command Injection, which is a well-documented weakness that has been exploited in numerous network device attacks. The lack of authentication requirements makes this vulnerability particularly severe as it can be exploited from any network location without prior access credentials.
The operational impact of this vulnerability extends beyond simple unauthorized access, as it provides complete control over the affected network devices. Attackers can leverage this vulnerability to modify device configurations, install malicious software, redirect network traffic, or use the compromised devices as entry points for further attacks within the network. The vulnerability creates a persistent backdoor that remains active until the device is rebooted or the firmware is updated. This type of vulnerability aligns with ATT&CK technique T1059.001 for Command and Scripting Interpreter, specifically focusing on the execution of commands through the device's shell interface. Network administrators face significant risks including potential data breaches, man-in-the-middle attacks, and the compromise of entire local networks that depend on these devices for connectivity.
Mitigation strategies for CVE-2015-9551 should prioritize immediate firmware updates from TOTOLINK, as the vendor has likely released patches addressing this specific vulnerability. Organizations should implement network segmentation to isolate these devices from critical infrastructure and apply firewall rules to restrict access to the management interfaces. Additionally, network monitoring should be enhanced to detect unusual command execution patterns or unauthorized access attempts. The vulnerability highlights the importance of secure coding practices and input validation in embedded systems, particularly those with web interfaces. Security teams should also consider implementing network access control lists to prevent external access to administrative ports and ensure that default credentials are changed immediately upon device deployment. Regular vulnerability assessments and penetration testing should be conducted to identify similar issues in other network equipment within the organization's infrastructure.