CVE-2021-45547 in R7850
Summary
by MITRE • 12/26/2021
Certain NETGEAR devices are affected by command injection by an authenticated user. This affects R7850 before 1.0.5.74, R7900P before 1.4.2.84, R7960P before 1.4.2.84, R8000 before 1.0.4.74, R8000P before 1.4.2.84, RAX200 before 1.0.4.120, RAX75 before 1.0.4.120, RAX80 before 1.0.4.120, RBK752 before 3.2.17.12, RBK852 before 3.2.17.12, RBR750 before 3.2.17.12, RBR850 before 3.2.17.12, RBS750 before 3.2.17.12, and RBS850 before 3.2.17.12.
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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 authenticated users to execute arbitrary commands on affected devices. The vulnerability stems from improper input validation within the web interface of these routers, specifically in the handling of parameters passed to system commands. Attackers who have gained access to the device through legitimate authentication can exploit this weakness to run malicious commands with the privileges of the web server process, effectively compromising the entire network infrastructure. The affected models span multiple product lines including the R7850, R7900P, R8000, and various RAX and RBK series devices, indicating a widespread issue across NETGEAR's consumer and small business networking portfolio.
The technical implementation of this vulnerability aligns with CWE-77 and CWE-88, which describe command injection flaws where user-supplied input is directly incorporated into system commands without proper sanitization. The flaw manifests when authenticated users submit specially crafted input through web forms or API endpoints that are subsequently passed to shell commands. This allows attackers to chain together multiple commands or execute system-level operations such as spawning reverse shells, modifying firewall rules, accessing sensitive configuration files, or even installing persistent backdoors. The vulnerability is particularly concerning because it requires only authentication access, which can often be obtained through default credentials, weak password policies, or social engineering attacks. The affected firmware versions indicate that this issue has persisted across multiple releases, suggesting inadequate input validation mechanisms were not properly addressed in security patches.
The operational impact of this vulnerability extends far beyond simple privilege escalation, as compromised routers can serve as persistent footholds for attackers to conduct network reconnaissance, redirect traffic, or establish command and control channels. Network administrators face significant risks including unauthorized access to internal network resources, data exfiltration, and potential use as launching points for broader attacks against connected devices. The vulnerability's exploitation can result in complete network compromise, especially in environments where these devices serve as primary gateways or where they are configured with weak security postures. Organizations may experience service disruption, compliance violations, and potential legal consequences if networks are compromised through this vector. The widespread nature of affected models means that numerous households and small businesses could be impacted, with implications for both personal privacy and business continuity.
Mitigation strategies must address both immediate remediation and long-term security hardening measures. Organizations should prioritize updating all affected devices to the latest firmware versions released by NETGEAR, specifically targeting the version numbers mentioned in the CVE description. Network segmentation should be implemented to limit the potential impact of a compromised device, while implementing strong authentication mechanisms including multi-factor authentication and regular password rotation. Network monitoring systems should be enhanced to detect unusual traffic patterns or command execution attempts that may indicate exploitation. Access controls should be strictly enforced to limit who can authenticate to these devices, and default credentials should be changed immediately across all affected hardware. The vulnerability also underscores the importance of secure coding practices and input validation, as highlighted in the ATT&CK framework under T1059 for command and scripting interpreter. Regular security audits of network infrastructure and implementation of intrusion detection systems can help identify and respond to exploitation attempts. Organizations should also consider implementing network access control policies that limit administrative access to only necessary personnel and establish monitoring procedures for detecting unauthorized configuration changes.