CVE-2024-57040: TP-Link TL-WR845N Auth Bypass Vulnerability

CVE-2024-57040 Overview

CVE-2024-57040 is a critical hardcoded credentials vulnerability affecting TP-Link TL-WR845N wireless routers. The vulnerability exists because the firmware contains a hardcoded password for the root account, which attackers can extract by analyzing the firmware binary or through brute force attacks with physical access to the device. This type of vulnerability (CWE-798: Use of Hard-coded Credentials) represents a fundamental security design flaw that cannot be mitigated through user configuration changes.

Critical Impact

Attackers who obtain the hardcoded root credentials can gain complete administrative control over affected TP-Link TL-WR845N routers, potentially compromising all network traffic and connected devices.

Affected Products

• TP-Link TL-WR845N(UN)_V4 Firmware Version 200909
• TP-Link TL-WR845N(UN)_V4 Firmware Version 190219
• TP-Link TL-WR845N(UN)_V4 Firmware Version 201214

Discovery Timeline

• 2025-02-26 - CVE-2024-57040 published to NVD
• 2025-04-07 - Last updated in NVD database

Technical Details for CVE-2024-57040

Vulnerability Analysis

This vulnerability stems from a hardcoded credential issue in the TP-Link TL-WR845N router firmware. The root account password is embedded directly within the firmware binary, making it discoverable through firmware analysis techniques. Security researchers documented this vulnerability by extracting and analyzing the hashed password from the router's firmware image.

The presence of hardcoded credentials in IoT devices like routers is particularly dangerous because it provides attackers with a persistent, unchangeable authentication bypass. Unlike user-configurable passwords that can be updated, hardcoded credentials remain constant across all devices running the same firmware version, creating a single point of failure for the entire product line.

Root Cause

The root cause is the use of hardcoded credentials (CWE-798) in the firmware development process. The root account password was embedded directly into the firmware binary during the development phase, likely for debugging or manufacturing purposes, and was not removed before production release. This practice violates secure development principles that mandate unique, configurable credentials for privileged accounts.

Attack Vector

The attack vector for CVE-2024-57040 operates through two primary methods:

Firmware Analysis Attack:

1. Attacker downloads the publicly available firmware update file from TP-Link's website
2. Firmware image is extracted and analyzed using tools like binwalk
3. The /etc/passwd or /etc/shadow equivalent is located within the filesystem
4. The hashed root password is extracted and subjected to offline cracking
5. Once cracked, the plaintext password works on all devices running affected firmware versions

Physical Access Attack:

1. Attacker gains physical access to the router
2. Serial console or JTAG interface is used to access the system
3. Brute force attack is conducted against the root account
4. Successful authentication grants full administrative control

The vulnerability allows network-based exploitation once credentials are known, as the root account can authenticate over SSH or other management interfaces if enabled.

Detection Methods for CVE-2024-57040

Indicators of Compromise

• Unexpected root-level login attempts or sessions on affected TP-Link routers
• Configuration changes made outside of normal administrative windows
• Modified DNS settings redirecting traffic to unknown servers
• Unauthorized firmware modifications or downgrade attempts
• Unusual outbound connections from the router to unknown external IP addresses

Detection Strategies

• Monitor network traffic for SSH or Telnet connections to TP-Link routers from unauthorized sources
• Implement network segmentation to isolate management interfaces from untrusted networks
• Deploy intrusion detection systems (IDS) rules to alert on authentication attempts to router management interfaces
• Audit firmware versions across all TP-Link TL-WR845N devices in the environment

Monitoring Recommendations

• Enable logging on all TP-Link router management interfaces where possible
• Centralize logs from network infrastructure devices to a SIEM platform
• Create alerts for any root account authentication events on affected devices
• Monitor for firmware extraction or analysis tools on endpoint systems that may indicate reconnaissance activity

How to Mitigate CVE-2024-57040

Immediate Actions Required

• Identify all TP-Link TL-WR845N V4 routers in your environment and verify firmware versions
• Disable remote management interfaces (SSH, Telnet, HTTP/HTTPS management) from untrusted networks
• Implement network segmentation to restrict access to router management interfaces
• Consider replacing affected devices with hardware from vendors that follow secure credential management practices
• Monitor TP-Link's security advisories for potential firmware updates addressing this vulnerability

Patch Information

As of the last NVD update on 2025-04-07, no official patch has been released by TP-Link to address this vulnerability. The affected firmware versions include 190219, 200909, and 201214. Organizations should check TP-Link's official support page for any security updates and subscribe to their security notification channels.

For additional technical analysis of the hardcoded password issue, see the IIITA IoT Hashed Password Analysis documentation.

Workarounds

• Disable all remote management access to affected routers and only allow console-based administration
• Place affected routers behind a firewall that restricts inbound management connections to authorized IP addresses only
• Implement 802.1X or MAC filtering to limit which devices can connect to the router's management network
• Consider deploying a VPN solution to secure management traffic if remote administration is required
• Replace affected devices with models that do not contain hardcoded credentials

# Network isolation example using iptables on a gateway device
# Block external access to router management ports

# Block SSH access to router from external networks
iptables -A FORWARD -d 192.168.1.1 -p tcp --dport 22 -j DROP

# Block Telnet access to router from external networks
iptables -A FORWARD -d 192.168.1.1 -p tcp --dport 23 -j DROP

# Block HTTP/HTTPS management access from external networks
iptables -A FORWARD -d 192.168.1.1 -p tcp --dport 80 -j DROP
iptables -A FORWARD -d 192.168.1.1 -p tcp --dport 443 -j DROP

# Allow management only from trusted admin workstation
iptables -A FORWARD -s 192.168.1.100 -d 192.168.1.1 -p tcp --dport 80 -j ACCEPT