Description

A vulnerability was identified in D-Link DIR-842 2.01.B04. This impacts an unknown function of the file /etc/vsftpd.conf of the component vsftpd. Such manipulation leads to incorrect default permissions. It is possible to launch the attack remotely. A high complexity level is associated with this attack. The exploitability is said to be difficult.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "3.1",
  "pubDate": "2026-08-15T12:16:32.543Z",
  "pubdate": "2026-08-15T12:16:32.543Z",
  "executiveSummary": "A security vulnerability has been identified within the vsftpd component implemented in the D-Link DIR-842 router running firmware version 2.01.B04. Specifically, the flaw exists within the configuration file located at /etc/vsftpd.conf, where improper handling results in incorrect default permissions.\nThis vulnerability leads to an improper permissions security issue, allowing unauthorized actors to potentially interact with the FTP service under weakened access controls. The vulnerability type is classified as incorrect default permissions, which impacts the overall file-system security posture of the affected network device.\nThe attack vector for this vulnerability is remote, enabling malicious actors to target the service across a network boundary. However, exploiting this condition involves a high level of complexity and is characterized as difficult in terms of overall exploitability.\nRisk implications include potential exposure of sensitive file configurations or unauthorized modifications due to overly permissive access controls. Mitigation requires careful review and hardening of the underlying vsftpd configuration files and adherence to the principle of least privilege.",
  "technicalDetails": "The vulnerability resides within the vsftpd component utilized by the D-Link DIR-842 router running firmware version 2.01.B04. The root cause of the issue stems from an insecure default configuration defined within the /etc/vsftpd.conf file.\nDuring the initialization or packaging of the vsftpd service, the file permissions associated with the configuration file or the resulting directories managed by the FTP daemon are instantiated with insecure default values. This deviation from secure baseline configurations permits broader access than intended by system security standards.\nThe affected component is the vsftpd FTP server daemon, specifically interacting with parameters defined in /etc/vsftpd.conf. The vulnerability manifests via remote attack vectors, requiring network connectivity to the targeted device's exposed management or service ports.\nExploitation of this vulnerability is categorized as having high complexity and is considered difficult to execute successfully. Attackers must leverage specific network conditions or existing exposure vectors to interact with the misconfigured FTP service.\nThe step-by-step attack flow involves an external adversary identifying the exposed vsftpd service on the target D-Link DIR-842 device. Subsequently, the attacker attempts to interact with the service or leverage the incorrect default permissions to read, write, or manipulate files governed by the misconfigured daemon.\nPost-exploitation impact includes the potential unauthorized access to sensitive files, tampering with device configurations, or leveraging the weakened permission structure to facilitate further compromise of the underlying operating system environment of the router."
}