D-Link End-of-Life (EOL) NAS Hard-Coded Credentials Vulnerability (CVE-2024-3272) Technical Advisory
Executive & SecOps Summary
SECOPS ASSESSMENTAll firmware versions of legacy D-Link NAS models DNS-320L, DNS-325, DNS-327L, and DNS-340L.
Remote unauthenticated attackers can bypass authentication using hard-coded credentials, leading to complete system compromise and arbitrary code execution.
Since these devices are End-of-Life (EOL) and will not receive security patches, they must be immediately decommissioned and replaced.
Affected Products & Version Scope
Remediation & Live Workaround Commands
PATCH & WORKAROUND1. Official Patch & Version Upgrade Commands
No official patches or firmware updates are available from D-Link as these products have reached End-of-Life (EOL) status. The vendor strongly recommends retiring and replacing these devices immediately.
2. Temporary Workaround & Hardening Configuration
If immediate replacement is not feasible, isolate the NAS from the public internet. Block all inbound traffic to the web administration ports (80, 443) using network firewalls or local iptables rules.
# Block all external access to the NAS IP (e.g., 192.168.1.100) on HTTP/HTTPS ports
iptables -A INPUT -p tcp -s 0.0.0.0/0 --dport 80 -d 192.168.1.100 -j DROP
iptables -A INPUT -p tcp -s 0.0.0.0/0 --dport 443 -d 192.168.1.100 -j DROP
# Allow access only from a trusted administration subnet (e.g., 10.0.0.0/24)
iptables -I INPUT -p tcp -s 10.0.0.0/24 --dport 443 -d 192.168.1.100 -j ACCEPT3. Log Audit & IoC Verification Commands
Inspect web server access logs for suspicious requests targeting the vulnerable CGI script with the hard-coded user parameter.
# Scan web server access logs for exploitation attempts
grep -i 'nas_sharing.cgi' /var/log/httpd/access_log | grep -i 'user=messagebus'
# Check for active unauthorized shell connections on the NAS
netstat -an | grep -E ':(80|443)' | grep 'ESTABLISHED'Stop Exposing VPN Ports to the Internet — Switch to Zero-Trust Access
Eliminate public-facing VPN concentrators and firewall management ports with identity-first Zero-Trust Network Access.
Technical Root Cause & Exploitation Mechanics
1. Vulnerability Overview & Root Cause
This vulnerability (CVE-2024-3272) is a critical hard-coded credentials flaw (CWE-798) found in the web management interface of legacy D-Link NAS devices. The root cause lies within the HTTP GET request handler of the /cgi-bin/nas_sharing.cgi component. The application logic inherently trusts a hard-coded system account named messagebus with empty or static credentials, failing to perform proper authentication validation.
2. Exploitation Mechanics & Attack Scenario
An attacker can exploit this vulnerability by sending a crafted HTTP GET request to the target device's /cgi-bin/nas_sharing.cgi endpoint. By passing the parameter user=messagebus along with shell metacharacters or command injection payloads, the CGI script processes the request under the context of the privileged messagebus user. This allows the attacker to bypass authentication entirely and execute arbitrary OS commands with root privileges remotely.
3. Infrastructure & Business Impact
With a CVSS score of 9.8 (Critical) and active exploitation tracked in CISA's KEV catalog, this vulnerability poses an extreme risk. Successful exploitation allows full administrative control over the NAS device, leading to unauthorized data exfiltration, ransomware deployment on backups, and potential lateral movement into the internal corporate network.
Official Vendor Advisories & References
** UNSUPPORTED WHEN ASSIGNED ** A vulnerability, which was classified as very critical, has been found in D-Link DNS-320L, DNS-325, DNS-327L and DNS-340L up to 20240403. This issue affects some unknown processing of the file /cgi-bin/nas_sharing.cgi of the component HTTP GET Request Handler. The manipulation of the argument user with the input messagebus leads to hard-coded credentials. The attack may be initiated remotely. The exploit has been disclosed to the public and may be used. The associated identifier of this vulnerability is VDB-259283. NOTE: This vulnerability only affects products that are no longer supported by the maintainer. NOTE: Vendor was contacted early and confirmed immediately that the product is end-of-life. It should be retired and replaced.
Frequently Asked SecOps Questions (CVE-2024-3272)
FAQQ1. How critical is CVE-2024-3272 and is it actively exploited in the wild?
CVE-2024-3272 is rated CVSS 9.8 (CRITICAL) with a 30-day EPSS exploitation probability of 98.1%. It is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, requiring immediate emergency remediation.
Q2. Which vendors and products are affected by CVE-2024-3272?
Primary impacted vendors include d-link across dns-320l, dns-325, dns-327l, dns-340l. Scope summary: D-Link DNS-320L, DNS-325, DNS-327L, and DNS-340L (All versions; End-of-Life status)
Q3. What temporary mitigations or workarounds exist for CVE-2024-3272 before patching?
[Mitigation] Since these devices are End-of-Life (EOL) and will not receive security patches, they must be immediately decommissioned and replaced. Follow the CLI remediation commands and interactive SecOps checklist on this page to restrict exposure prior to your maintenance window.
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