CVE-2022-48121 in A7100RU
Summary
by MITRE • 01/20/2023
TOTOlink A7100RU V7.4cu.2313_B20191024 was discovered to contain a command injection vulnerability via the rsabits parameter in the setting/delStaticDhcpRules function.
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Analysis
by VulDB Data Team • 04/04/2025
The vulnerability identified as CVE-2022-48121 represents a critical command injection flaw within the TOTOlink A7100RU router firmware version V7.4cu.2313_B20191024. This issue resides in the web interface's backend processing logic where the rsabits parameter within the setting/delStaticDhcpRules function fails to properly sanitize user input before executing system commands. The vulnerability allows remote attackers to inject malicious commands that are subsequently executed with the privileges of the web server process, potentially leading to complete system compromise. The affected device operates under a typical router operating system environment where web interfaces communicate with underlying system binaries through command execution mechanisms.
This command injection vulnerability falls under the CWE-77 category known as "Command Injection" and aligns with ATT&CK technique T1059.001 for Command and Scripting Interpreter. The flaw manifests when the rsabits parameter receives unvalidated input from the web interface, bypassing proper input validation and sanitization mechanisms. The vulnerability is particularly dangerous because it allows arbitrary command execution without requiring authentication, making it accessible to remote attackers. The specific function setting/delStaticDhcpRules suggests this occurs within the dynamic host configuration protocol management subsystem, where the system processes static dhcp rules for network device management. The parameter rsabits likely controls cryptographic bit settings for security protocols, but the lack of input validation creates a direct pathway for command injection attacks.
The operational impact of this vulnerability extends beyond simple remote code execution to encompass complete network infrastructure compromise. An attacker could leverage this vulnerability to gain root access to the router, potentially enabling them to modify network configurations, redirect traffic through malicious proxies, or establish persistent backdoors. The router's role as a network gateway means that successful exploitation could provide attackers with access to all devices within the local network segment. Additionally, the vulnerability affects the device's security posture by allowing attackers to potentially manipulate DNS settings, modify firewall rules, or disable security features. The long-term implications include potential data exfiltration from networked devices and the ability to use the compromised router as a pivot point for attacking other systems within the network.
Mitigation strategies for CVE-2022-48121 should prioritize immediate firmware updates from TOTOlink to address the input validation deficiencies. Network administrators should implement network segmentation and monitoring to detect anomalous command execution patterns that might indicate exploitation attempts. The principle of least privilege should be enforced by ensuring that the web server process operates with minimal required permissions and that command execution capabilities are restricted. Additional protective measures include implementing web application firewalls to filter suspicious input patterns, conducting regular security audits of web interface parameters, and establishing network monitoring rules to detect command injection attempts. Organizations should also consider deploying intrusion detection systems that can identify the specific command patterns associated with this vulnerability. The vulnerability highlights the importance of input validation and secure coding practices, particularly in network device management interfaces where insufficient validation can lead to complete system compromise. Regular security assessments of embedded systems and firmware components remain essential to identify and remediate similar vulnerabilities before they can be exploited in real-world scenarios.