Vulnerability Report

Critical Vulnerability in D-LINK NAS Devices

By

Matthew Fagan, Access Point Consulting

By

Access Point Consulting

Summary

A critical vulnerability has been confirmed in select D-Link NAS devices, including DNS-340L, DNS-320L, DNS-327L, and DNS-325. Evidence suggests that other D-Link NAS devices may also be affected. The vulnerability, identified as CVE-2024-3273 (CVSS: 9.8), exploits the /cgi-bin/nas_sharing.cgi component of the HTTP GET Request Handler. By manipulating this component, an attacker can perform remote command injection to obtain hardcoded credentials. A publicly disclosed exploit developed by NetSecFish has confirmed the presence of this vulnerability. Network scans indicate that over 92,000 devices are affected.

Figure 1: NetSecFish Internet Scan (Github)

Impact Assessment

This vulnerability leverages two main flaws: a backdoor that allows username and password parameters to be passed without authentication, and a system parameter that enables command execution. Exploitation can lead to the retrieval of the device's password, granting unauthorized access, allowing configuration changes, denial of service, and command execution.

Figure 2: NetSecFish Exploit (Github)

Affected Devices

The following devices are mentioned in D-Link’s security advisory. Devices confirmed to be vulnerable by NetSecFish are in bold:

  • DNS-120
  • DNR-202L
  • DNS-315L
  • DNS-320
  • DNS-320L
  • DNS-320LW
  • DNS-321
  • DNR-322L
  • DNS-323
  • DNS-325
  • DNS-326
  • DNS-327L
  • DNR-326
  • DNS-340L
  • DNS-343
  • DNS-345
  • DNS-726-4
  • DNS-1100-4
  • DNS-1200-05
  • DNS-1550-04

Remediation

Unfortunately, all affected devices are End-of-Sale (EoS) and End-of-Life (EoL), meaning they no longer receive security patches or updates. D-Link recommends replacing these devices with newer hardware as there is no official fix for this vulnerability.

What It Means for You

If you use any D-Link NAS device, it is time to consider a replacement. Research newer Network Attached Storage devices, assess your business requirements, and plan for a replacement.

Business Implications

Exploitation of this vulnerability can lead to unauthorized access to the NAS system, compromising all files on the device. Attackers can execute commands and conduct denial-of-service attacks, leading to potential data, reputational, and monetary losses.

Recommendations

  1. Replace EoL Devices - Plan and secure upgrades for End-of-Life devices before they stop receiving updates. Moving away from D-Link NAS devices is recommended.
  1. Secure Network - Ensure WIFI encryption is enabled with a unique password. Avoid direct internet connections for NAS devices and use network segmentation to prevent exploitation.
  1. Perform Backups - Regularly back up data from your NAS to prevent data loss if access is compromised or devices are locked down.
  1. Utilize Encryption - Implement AES-256 encryption for data at rest and in transit to protect against data theft. Without the proper decryption key, the data remains inaccessible to unauthorized users.

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