CVE-2021-45531 in D6220
Summary
by MITRE • 12/26/2021
NETGEAR D6220 devices before 1.0.0.76 are affected by command injection by an authenticated user.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 12/28/2021
The vulnerability identified as CVE-2021-45531 affects NETGEAR D6220 wireless routers and is categorized as a command injection flaw that can be exploited by authenticated users. This issue resides within the device's web-based management interface where improper input validation allows malicious commands to be executed with the privileges of the authenticated user. The vulnerability stems from insufficient sanitization of user-supplied input parameters that are subsequently passed to system commands without adequate filtering or encoding mechanisms.
The technical implementation of this vulnerability involves the exploitation of a classic command injection vector where user-controllable data is directly incorporated into system command execution flows. When an authenticated user submits specific input through the web interface, the application fails to properly validate or sanitize this data before using it in shell command invocations. This design flaw enables attackers to inject arbitrary commands that are then executed on the underlying operating system. The vulnerability is particularly concerning because it requires only authentication, which is typically achievable through default credentials or compromised user accounts, making it accessible to threat actors with minimal initial access requirements.
From an operational impact perspective, this vulnerability presents significant risks to network security and device integrity. An attacker who gains access to the device through legitimate authentication can execute arbitrary commands with the privileges of the web application user, potentially leading to complete device compromise. The attack surface extends beyond simple command execution to include potential lateral movement within the network, data exfiltration, and the establishment of persistent backdoors. The vulnerability affects devices running firmware versions prior to 1.0.0.76, indicating that this is a known issue that was addressed in a subsequent patch release, though many devices may remain unpatched in production environments.
The vulnerability aligns with CWE-77 and CWE-78 categories from the Common Weakness Enumeration framework, which specifically addresses command injection vulnerabilities where user input is improperly handled in system command contexts. This weakness enables attackers to execute arbitrary commands on the target system, potentially leading to complete system compromise. The attack pattern follows the MITRE ATT&CK framework's technique T1059.001 for command and script injection, where adversaries leverage legitimate system tools to execute malicious code. The authenticated nature of the vulnerability means that threat actors can exploit this weakness without requiring additional network-level access or complex reconnaissance, making it particularly dangerous in environments where default credentials are not changed or where user accounts are compromised.
Mitigation strategies for this vulnerability primarily focus on immediate firmware updates to version 1.0.0.76 or later, which contain the necessary patches to address the input validation deficiencies. Network administrators should also implement additional security controls including disabling unnecessary web management interfaces, restricting access to management ports through firewall rules, and implementing strong authentication mechanisms with multi-factor authentication where possible. Regular security assessments and vulnerability scanning should be conducted to identify unpatched devices within the network infrastructure, while monitoring for suspicious command execution patterns or unauthorized access attempts. The remediation process should also include changing default credentials across all affected devices and implementing network segmentation to limit the potential impact of successful exploitation attempts.