CVE-2020-25218 in GRP261x
Summary
by MITRE • 03/29/2021
Grandstream GRP261x VoIP phone running firmware version 1.0.3.6 (Base) allow Authentication Bypass in its administrative web interface.
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Analysis
by VulDB Data Team • 04/06/2021
The Grandstream GRP261x VoIP phone represents a critical security vulnerability identified as CVE-2020-25218, which exposes a significant authentication bypass flaw in its administrative web interface. This vulnerability specifically affects firmware version 1.0.3.6 and potentially other variants within the base release, creating a severe risk for organizations relying on these devices for voice communication infrastructure. The flaw allows unauthorized actors to gain administrative access without proper authentication credentials, fundamentally undermining the security posture of the affected telephony systems.
The technical nature of this vulnerability stems from improper authentication mechanisms within the web interface implementation. The administrative interface fails to properly validate user credentials or enforce access controls, enabling attackers to bypass the standard authentication process entirely. This authentication bypass occurs at the application layer and affects the web-based management portal that administrators use to configure and manage the VoIP phone settings. The flaw represents a classic weakness in access control implementation that aligns with CWE-287, which addresses improper authentication issues in software systems. Attackers can exploit this vulnerability by directly accessing administrative endpoints without providing valid login credentials, potentially gaining full control over device configuration and network settings.
The operational impact of this vulnerability extends far beyond simple unauthorized access, as it enables comprehensive control over the affected VoIP infrastructure. An attacker who successfully exploits this vulnerability can modify phone settings, configure call routing, access network configurations, and potentially use the device as a pivot point for further attacks within the network. The administrative web interface typically provides access to sensitive functions such as SIP account configuration, firewall settings, and network parameters that could be leveraged to disrupt services or establish persistent access. This vulnerability directly maps to ATT&CK technique T1078 which covers valid accounts and credential access, and T1566 which involves credential harvesting through various attack vectors. Organizations may face service disruption, unauthorized call routing, data interception, and potential network compromise through this single vulnerability.
Mitigation strategies for CVE-2020-25218 should prioritize immediate firmware updates from Grandstream to address the authentication bypass flaw. Network segmentation and access control measures can help limit exposure by restricting direct access to VoIP device management interfaces from external networks. Implementing additional authentication layers such as two-factor authentication for administrative access can provide defense in depth. Regular security audits of VoIP infrastructure should include verification of authentication mechanisms and access controls. Organizations should also monitor network traffic for suspicious activity related to administrative interface access and implement intrusion detection systems to identify potential exploitation attempts. The vulnerability highlights the importance of maintaining up-to-date firmware and following security best practices for networked devices, particularly those handling sensitive communication infrastructure. This flaw underscores the critical need for proper authentication implementation in network management interfaces and demonstrates how seemingly minor access control failures can result in complete system compromise.