D-Link DIR-300 Router Cleartext Password Storage Vulnerability (CVE-2011-4723) Analysis and Mitigation Guide
Executive & SecOps Summary
SECOPS ASSESSMENTD-Link DIR-300 wireless router devices
Adjacent or context-dependent attackers can retrieve plaintext administrator credentials stored on the device, leading to complete compromise of the router
Since this is a legacy End-of-Life (EoL) device, immediately replace it with a modern supported router, or restrict administrative access to the absolute minimum
Affected Products & Version Scope
Remediation & Live Workaround Commands
PATCH & WORKAROUND1. Official Patch & Version Upgrade Commands
No official security patches are available from the vendor as this product has reached End-of-Life (EoL). The recommended action is to decommission the device and replace it with a modern, supported router. If replacement is delayed, installing an open-source alternative firmware like OpenWrt can be considered at your own risk.
# Note: Ensure hardware compatibility before flashing alternative firmware.
# Example of updating packages on an OpenWrt-flashed device to maintain security:
opkg update && opkg upgrade uhttpd rpcd2. Temporary Workaround & Hardening Configuration
To mitigate exposure before replacing the hardware, disable remote management and restrict local administration access using firewall rules.
# Block all HTTP/HTTPS management traffic except from a trusted administration IP (e.g., 192.168.0.100)
iptables -A INPUT -p tcp --dport 80 -s ! 192.168.0.100 -j DROP
iptables -A INPUT -p tcp --dport 443 -s ! 192.168.0.100 -j DROP3. Log Audit & IoC Verification Commands
Audit web server access logs for unauthorized attempts to download configuration files or access sensitive paths.
# Search access logs for suspicious requests targeting configuration or binary backup files
grep -Ei '(\.cfg|\.bin|config|settings)' /var/log/lighttpd/access.log || trueStop 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-2011-4723) stems from a fundamental credential management flaw in the D-Link DIR-300 router. The device stores administrator passwords in cleartext (plaintext) within its configuration files or internal database without proper encryption or hashing (CWE-312). This design flaw allows any attacker with access to the system configuration vectors to read the credentials directly.
2. Exploitation Mechanics & Attack Scenario
An attacker positioned on the local or adjacent network can exploit this vulnerability by accessing the device's configuration backup files or leveraging other directory traversal/unauthenticated access vectors to read the configuration. Once the plaintext password is extracted, the attacker can authenticate via the web management console or Telnet interface, allowing them to modify DNS settings, upload malicious firmware, or intercept network traffic.
3. Infrastructure & Business Impact
If this device is deployed within a corporate branch, SOHO, or development environment, its compromise allows attackers to perform Man-in-the-Middle (MitM) attacks on all internal traffic. Given its inclusion in the CISA KEV catalog, this vulnerability has been actively exploited in the wild, making immediate decommissioning or isolation critical.
Official Vendor Advisories & References
The D-Link DIR-300 router stores cleartext passwords, which allows context-dependent attackers to obtain sensitive information via unspecified vectors.
Frequently Asked SecOps Questions (CVE-2011-4723)
FAQQ1. How critical is CVE-2011-4723 and is it actively exploited in the wild?
CVE-2011-4723 is rated CVSS 5.7 (MEDIUM) with a 30-day EPSS exploitation probability of 3.1%. It is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, requiring immediate emergency remediation.
Q2. Which vendors and products are affected by CVE-2011-4723?
Primary impacted vendors include d-link across dir-300. Scope summary: All firmware versions of D-Link DIR-300 routers (End-of-Life status)
Q3. What temporary mitigations or workarounds exist for CVE-2011-4723 before patching?
[Mitigation] Since this is a legacy End-of-Life (EoL) device, immediately replace it with a modern supported router, or restrict administrative access to the absolute minimum Follow the CLI remediation commands and interactive SecOps checklist on this page to restrict exposure prior to your maintenance window.
Generate an Internal Engineering Notice or CISO Report for CVE-2011-4723
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