CVE-2019-10041 in DIR-816 A2
Summary
by MITRE
The D-Link DIR-816 A2 1.11 router only checks the random token when authorizing a goform request. An attacker can get this token from dir_login.asp and use an API URL /goform/form2userconfig.cgi to edit the system account without authentication.
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Analysis
by VulDB Data Team • 08/07/2023
The D-Link DIR-816 A2 1.11 router presents a critical authentication bypass vulnerability that fundamentally undermines the device's security model. This flaw resides in the router's web-based administration interface where the authentication mechanism is improperly implemented, relying solely on a random token for authorization validation. The vulnerability stems from the router's failure to maintain proper session management and authentication state verification, creating a pathway for unauthorized administrative access that directly violates established security principles for network device management.
The technical implementation of this vulnerability demonstrates a classic weak authentication pattern where the system generates a random token for authorization purposes but fails to validate that token against a proper session context or user credentials. Attackers can extract this token from the dir_login.asp page which serves as the initial authentication landing page, then leverage this token to make direct API calls to the /goform/form2userconfig.cgi endpoint. This design flaw represents a clear violation of the principle of least privilege and proper access control enforcement, as the system should require proper authentication credentials before allowing any administrative configuration changes regardless of token presence.
The operational impact of this vulnerability is severe and far-reaching for any network environment utilizing affected D-Link routers. An attacker with remote access to the network can completely compromise the device's administrative functions without needing valid user credentials, effectively granting full control over the router's configuration, including but not limited to network settings, firewall rules, user accounts, and security policies. This vulnerability enables attackers to establish persistent access points, redirect traffic, disable security features, and potentially use the compromised device as a launch point for further attacks within the network. The implications extend beyond simple unauthorized access as this vulnerability can be exploited by remote attackers without requiring physical access or local network presence, making it particularly dangerous in enterprise and home network environments.
The vulnerability aligns with CWE-305 Authentication Bypass Using an Alternate Path or Channel, which describes situations where authentication can be bypassed by using a different access path or method than the intended authentication mechanism. This weakness directly maps to the ATT&CK technique T1078 Valid Accounts, as attackers can leverage the compromised administrative access to maintain persistence and escalate privileges within the network. The lack of proper session management and authentication state verification creates an attack surface that can be exploited through automated tools, making the vulnerability particularly attractive to threat actors seeking to establish long-term access to network infrastructure. Organizations should implement immediate mitigations including firmware updates from D-Link, network segmentation to limit access to administrative interfaces, and monitoring for suspicious API access patterns to prevent exploitation of this vulnerability.