CVE-2020-25366 in DIR-823G
Summary
by MITRE • 11/04/2021
An issue in the component /cgi-bin/upload_firmware.cgi of D-Link DIR-823G REVA1 1.02B05 allows attackers to cause a denial of service (DoS) via unspecified vectors.
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Analysis
by VulDB Data Team • 11/09/2021
The vulnerability identified as CVE-2020-25366 affects the D-Link DIR-823G REVA1 router model running firmware version 1.02B05. This issue resides within the /cgi-bin/upload_firmware.cgi component which handles firmware upload functionality through a web interface. The vulnerability represents a denial of service condition that can be triggered by attackers exploiting unspecified vectors within the firmware upload process. Such vulnerabilities in network device firmware represent significant security concerns as they can be leveraged to disrupt network operations and potentially create opportunities for further exploitation.
The technical flaw manifests in the improper handling of input validation within the firmware upload mechanism. When an attacker submits a malformed or malicious firmware file through the upload.cgi script, the system fails to properly validate the incoming data before processing it. This lack of proper input sanitization creates opportunities for the device to become unresponsive or crash entirely. The unspecified vectors suggest that multiple attack paths may exist, potentially including buffer overflows, memory corruption issues, or other input handling anomalies that cause the device to enter an unrecoverable state. The vulnerability falls under the category of improper input validation as defined by CWE-20, which is a fundamental weakness that leads to various security issues including denial of service conditions.
The operational impact of this vulnerability extends beyond simple service disruption as it can render the entire router inaccessible to legitimate users. Network administrators may find their devices unavailable for configuration changes, firmware updates, or normal operational procedures. The DoS condition can persist until manual intervention occurs, requiring device reboot or physical access to restore functionality. In enterprise environments, such vulnerabilities can lead to significant downtime and potential business disruption. The attack surface is particularly concerning given that the vulnerability exists in a web-based administrative interface that is commonly accessible from network segments. This aligns with ATT&CK technique T1499.004 which describes network denial of service attacks that can be executed through web interfaces and administrative portals.
Mitigation strategies for this vulnerability should include immediate firmware updates from D-Link to address the specific DoS condition in the upload_firmware.cgi component. Network administrators should implement network segmentation to limit access to administrative interfaces and consider restricting upload functionality to trusted network segments only. Additional defensive measures include monitoring for unusual upload activities and implementing web application firewalls to detect and block malformed requests targeting the vulnerable endpoint. The vulnerability highlights the importance of maintaining up-to-date firmware across all network devices and implementing proper access controls for administrative interfaces. Organizations should also consider disabling unnecessary administrative functions when not required and establish robust patch management procedures to address similar vulnerabilities in the future. Security monitoring should specifically target the upload_firmware.cgi endpoint for anomalous traffic patterns that may indicate exploitation attempts.