Severity: Unknown
Description: The DLink Router DIR-895L MFC v1.21b05 is vulnerable to credentials disclosure in telnet service through decompilation of firmware, that allows an unauthenticated attacker to gain access to the firmware and to extract sensitive data.
CVSS Score: N/A
D
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1. Risk Assessment
The D-Link DIR-895L router, version v1.21b05, possesses a vulnerability stemming from hardcoded credentials discoverable through firmware decompilation via the telnet service. This represents a moderate risk. The nature of the vulnerability – hardcoded credentials – indicates a design flaw allowing unauthenticated access to the firmware. The business impact could be significant, ranging from network compromise and data theft to potential disruption of services. The likelihood of exploitation is considered moderate, as it requires some technical skill to decompile the firmware, but doesn't require complex network conditions. The ease of exploitation is also moderate; once the firmware is decompiled, the credentials are readily available. Confidentiality is the most significant impact, as attackers can gain access to sensitive data stored within the router's configuration. Integrity could be compromised if attackers modify the router's configuration. Availability could be affected if the attacker disrupts the router's functionality. The EPSS score of 0.005070000 suggests a relatively low, but not insignificant probability of exploitation in the wild.
2. Potential Attack Scenarios
An attacker could exploit this vulnerability by first connecting to the D-Link DIR-895L router via telnet. They then download the firmware and use decompilation tools to disassemble it. Through examination of the decompiled firmware, the attacker discovers the hardcoded credentials. Using these credentials, the attacker can then log in to the router's web interface or via telnet with full administrative privileges. This allows the attacker to change DNS settings, redirect traffic, view network statistics, potentially access connected devices on the network, and even modify the router's firmware, potentially installing malware. The attacker could also use the router as a pivot point to attack other devices on the internal network.
3. Mitigation Recommendations
The primary mitigation is to upgrade the firmware to a version that addresses the hardcoded credentials. D-Link should release a firmware update that resolves this issue. In the interim, consider disabling the telnet service if not required. If telnet must be enabled, restrict access to trusted IP addresses only. Regularly monitor the router for unusual activity. Change the default administrator password to something strong and unique, though this may not fully mitigate the vulnerability if the hardcoded credentials provide an alternative access point. Refer to the Cybersecurity Works article for more details: https://cybersecurityworks.com/zerodays/cve-2020-29324-d-link-router-dir-895l-mfc-telnet-hardcoded-credentials.html
4. Executive Summary
The D-Link DIR-895L router, version v1.21b05, is vulnerable to a hardcoded credentials issue. This allows an attacker to gain access to the router's firmware and potentially the entire network without authentication, by decompiling the firmware and extracting the stored credentials. This could lead to data theft, network disruption, and potentially compromise of connected devices. While the exploitation requires some technical skill, the impact can be significant. We recommend upgrading the router's firmware as soon as possible to a version that addresses this vulnerability. Disabling telnet if not required is another immediate step. Addressing this vulnerability is important to protect our network and data from unauthorized access and potential disruption. The business impact of a successful attack could range from minor inconvenience to significant financial losses, depending on the sensitivity of the data stored and processed on the network.