CVE-2017-17746 in TL-SG108E
Summary
by MITRE
Weak access control methods on the TP-Link TL-SG108E 1.0.0 allow any user on a NAT network with an authenticated administrator to access the device without entering user credentials. The authentication record is stored on the device; thus if an administrator authenticates from a NAT network, the authentication applies to the IP address of the NAT gateway, and any user behind that NAT gateway is also treated as authenticated.
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Analysis
by VulDB Data Team • 12/17/2019
The CVE-2017-17746 vulnerability affects TP-Link TL-SG108E version 1.0.0 network switches, representing a critical access control flaw that undermines the device's security architecture. This vulnerability stems from improper session management where authentication tokens are tied to the network address rather than individual user sessions, creating a fundamental weakness in the device's authentication mechanism. The flaw specifically impacts devices operating within NAT environments where multiple internal users share a single public IP address, rendering the authentication system ineffective against unauthorized access attempts.
The technical implementation of this vulnerability exploits the device's failure to properly validate user sessions across network boundaries. When an administrator authenticates to the TL-SG108E switch, the authentication state is associated with the NAT gateway's public IP address rather than the specific user attempting access. This design flaw creates a scenario where any user within the same NAT network can leverage the existing authentication session without presenting valid credentials, effectively bypassing the authentication process entirely. The authentication records are stored locally on the device, making the session management vulnerable to this type of attack vector.
From an operational perspective, this vulnerability creates a significant security risk for organizations deploying TP-Link TL-SG108E switches in environments where NAT is prevalent. The impact extends beyond simple unauthorized access to encompass potential privilege escalation and lateral movement within network segments. An attacker positioned within the same NAT network as an authenticated administrator can gain full administrative access to the switch configuration, potentially compromising network management functions, altering routing tables, or modifying security policies. This vulnerability directly violates the principle of least privilege and undermines network segmentation strategies that rely on proper authentication controls.
The vulnerability aligns with CWE-613, which addresses inadequate session management, and represents a clear violation of the NIST SP 800-53 security control families related to access control and system and information integrity. From an ATT&CK framework perspective, this vulnerability maps to T1078 for Valid Accounts and T1566 for Phishing, as it enables unauthorized access through legitimate administrative sessions. The flaw also demonstrates characteristics of T1068, which involves exploiting vulnerabilities in system administration tools, and T1562, which covers disabling or modifying system protection mechanisms. Organizations should consider implementing network segmentation strategies, deploying additional access controls, and regularly auditing switch configurations to mitigate the risk associated with this vulnerability.
Mitigation strategies should include immediate firmware updates from TP-Link to address the authentication flaw, implementing network access controls to limit administrative access to trusted networks, and establishing monitoring procedures to detect unauthorized access attempts. Network administrators should also consider deploying additional authentication layers, such as multi-factor authentication or certificate-based authentication, to compensate for the inherent weakness in the device's session management. The vulnerability serves as a reminder of the importance of proper session handling in network devices and the need for robust authentication mechanisms that properly distinguish between individual users regardless of their network addressing scheme.