CVE-2021-45628 in CBR40
Summary
by MITRE • 12/26/2021
Certain NETGEAR devices are affected by command injection by an unauthenticated attacker. This affects CBR40 before 2.5.0.24, CBR750 before 3.2.18.2, RBK752 before 3.2.17.12, RBR750 before 3.2.17.12, RBS750 before 3.2.17.12, RBK852 before 3.2.17.12, RBR850 before 3.2.17.12, RBS850 before 3.2.17.12, RBS40V before 2.6.2.4, and RBW30 before 2.6.2.2.
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Analysis
by VulDB Data Team • 12/28/2021
This vulnerability represents a critical command injection flaw in NETGEAR networking equipment that allows unauthenticated attackers to execute arbitrary commands on affected devices. The vulnerability affects multiple models within the CBR40, CBR750, RBK752, RBR750, RBS750, RBK852, RBR850, RBS850, RBS40V, and RBW30 device families, with specific firmware versions indicating the scope of impacted systems. The flaw exists in the device's web interface handling of user input, where insufficient validation allows malicious command sequences to be passed directly to underlying system commands without proper sanitization or escaping mechanisms.
The technical exploitation of this vulnerability occurs through the web management interface of affected devices, where attackers can inject malicious commands via parameters that are processed without adequate input validation. This type of vulnerability falls under CWE-77 which specifically addresses command injection flaws, and represents a direct violation of secure coding principles that require proper input sanitization and parameterized command execution. The attack vector is particularly concerning because it requires no authentication credentials, making it accessible to any remote attacker who can reach the device's web interface. The vulnerability enables attackers to gain full administrative control over affected devices, potentially allowing them to modify network configurations, install malware, or use the devices as launch points for further attacks within the network.
The operational impact of this vulnerability extends beyond individual device compromise to potentially affect entire network infrastructures. When attackers gain control of networking equipment, they can manipulate routing tables, redirect traffic, monitor network communications, and establish persistent backdoors. This aligns with ATT&CK technique T1059 which covers command and scripting interpreter usage, and T1021 which covers remote services. The vulnerability creates a significant risk for organizations relying on these devices for network infrastructure, as compromised devices can serve as entry points for lateral movement within the network. Network segmentation may be bypassed when attackers control core routing equipment, potentially exposing sensitive internal systems to external threats.
Mitigation strategies should focus on immediate firmware updates from NETGEAR to address the command injection vulnerability, as well as network-level protections such as firewall rules that restrict access to device management interfaces from untrusted networks. Network administrators should implement monitoring for unusual command execution patterns and consider network segmentation to limit the potential impact of device compromise. The vulnerability demonstrates the critical importance of secure firmware development practices and regular security assessments of network infrastructure equipment. Organizations should also consider implementing network access controls that limit which systems can communicate with device management interfaces, and establish procedures for regular firmware updates and security patch management. Additionally, network administrators should perform thorough inventory assessments to identify all affected devices within their infrastructure and prioritize remediation efforts based on the criticality of each device's role in the network.