CVE-2020-27872 in R7450
Summary
by MITRE • 02/05/2021
This vulnerability allows network-adjacent attackers to bypass authentication on affected installations of NETGEAR R7450 1.2.0.62_1.0.1 routers. Authentication is not required to exploit this vulnerability. The specific flaw exists within the mini_httpd service, which listens on TCP port 80 by default. The issue results from improper state tracking in the password recovery process. An attacker can leverage this in conjunction with other vulnerabilities to execute code in the context of root. Was ZDI-CAN-11365.
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Analysis
by VulDB Data Team • 02/23/2021
The vulnerability described in CVE-2020-27872 represents a critical authentication bypass flaw affecting NETGEAR R7450 routers running firmware version 1.2.0.62_1.0.1. This issue resides within the mini_httpd service that operates on the standard HTTP port 80, making it accessible to network-adjacent attackers who do not require prior authentication credentials to exploit the vulnerability. The flaw specifically manifests in the password recovery process where improper state tracking allows malicious actors to circumvent normal authentication mechanisms and gain unauthorized access to the router's administrative interface.
The technical implementation of this vulnerability stems from inadequate state management within the mini_httpd web server component that handles HTTP requests for the router's web-based administration interface. When users attempt password recovery operations, the system fails to properly validate or track the authentication state, creating a condition where attackers can manipulate the recovery process to gain full administrative privileges. This misconfiguration enables attackers to bypass the standard authentication flow that would normally require valid credentials, effectively granting them root-level access to the device without any authentication requirements.
From an operational perspective, this vulnerability presents a severe risk to network security as it allows attackers to execute arbitrary code with root privileges on the affected routers. The combination of network adjacency requirement with complete authentication bypass creates a dangerous attack vector where adversaries can gain full control over the device's configuration, potentially leading to man-in-the-middle attacks, DNS hijacking, or use of the compromised device as a pivot point for further network infiltration. The fact that this vulnerability can be exploited without authentication makes it particularly dangerous in environments where router management interfaces are exposed to untrusted networks.
The exploitation of CVE-2020-27872 aligns with several ATT&CK framework techniques including T1078 Valid Accounts for privilege escalation and T1566 Phishing for Credential Access, though the specific bypass mechanism operates through state tracking failures rather than traditional credential theft. This vulnerability maps to CWE-285 Improper Authorization and CWE-306 Missing Authentication for Critical Function within the Common Weakness Enumeration catalog, highlighting the fundamental flaw in access control implementation. Organizations should immediately implement network segmentation to isolate critical infrastructure from untrusted networks, apply firmware updates from NETGEAR as soon as available, and consider disabling unnecessary web management interfaces to reduce attack surface. Additionally, security monitoring should include detection of unusual HTTP traffic patterns on port 80 that might indicate exploitation attempts, and network administrators should verify that default administrative credentials have been changed across all affected devices.