CVE-2025-71057: D-Link DSL-124 Session Hijacking Vulnerability

CVE-2025-71057 Overview

CVE-2025-71057 is a session hijacking vulnerability affecting the D-Link Wireless N 300 ADSL2+ Modem Router DSL-124 ME_1.00. This flaw stems from improper session management, which allows attackers to hijack authenticated user sessions by spoofing the IP address of a legitimate user. Successful exploitation grants unauthorized access to the router's administrative interface, potentially compromising network security and enabling further attacks on connected devices.

Critical Impact

Attackers can gain unauthorized access to router administration by hijacking sessions of authenticated users through IP address spoofing, potentially leading to complete network compromise.

Affected Products

• D-Link Wireless N 300 ADSL2+ Modem Router DSL-124 ME_1.00

Discovery Timeline

• 2026-02-26 - CVE-2025-71057 published to NVD
• 2026-02-26 - Last updated in NVD database

Technical Details for CVE-2025-71057

Vulnerability Analysis

This vulnerability is classified under CWE-287 (Improper Authentication), indicating a fundamental flaw in how the D-Link DSL-124 router validates and manages user sessions. The router relies on IP address as a primary or contributing factor for session validation, which is an inherently insecure practice. IP addresses can be easily spoofed by attackers on the same network segment or through various network manipulation techniques.

When a legitimate administrator authenticates to the router's web interface, the session management mechanism fails to implement proper security controls such as cryptographically secure session tokens, session binding to multiple client attributes, or adequate session timeout policies. This weakness allows an attacker who can determine or predict the IP address of an authenticated user to assume that user's session privileges.

Root Cause

The root cause of this vulnerability lies in the improper implementation of session management within the router's firmware. The device uses IP address-based session validation without implementing robust security measures such as secure session tokens tied to multiple client identifiers, HTTPS with proper certificate validation, or anti-spoofing protections. This design flaw allows attackers to bypass authentication by simply spoofing the source IP address of their requests to match that of an authenticated administrator.

Attack Vector

The attack is network-based and can be executed without prior authentication. An attacker positioned on the same network segment as the target router or with the ability to intercept and manipulate network traffic can exploit this vulnerability. The attack flow typically involves:

1. The attacker identifies the D-Link DSL-124 router and monitors network traffic to determine when an administrator session is active
2. The attacker identifies the IP address of the authenticated administrator
3. The attacker spoofs their source IP address to match the administrator's IP
4. The attacker sends requests to the router's administrative interface using the spoofed IP address
5. The router validates the session based on IP address and grants the attacker administrative access

The vulnerability requires no user interaction and can be exploited with low attack complexity. Additional technical details are available in the GitHub CVE Disclosures Repository.

Detection Methods for CVE-2025-71057

Indicators of Compromise

• Unusual administrative login activity or configuration changes on the router
• Multiple simultaneous sessions appearing to originate from the same IP address
• Network traffic anomalies indicating IP spoofing attempts on the local network
• Unexpected changes to router settings, DNS configuration, or firewall rules

Detection Strategies

• Monitor router access logs for suspicious administrative session activity or duplicate sessions
• Implement network monitoring to detect IP spoofing attempts using tools that can identify source IP address inconsistencies
• Deploy intrusion detection systems (IDS) with signatures for session hijacking patterns
• Enable logging on the router and forward logs to a centralized SIEM for analysis

Monitoring Recommendations

• Regularly review router administrative logs for unauthorized access attempts
• Set up alerts for configuration changes on network devices
• Monitor for ARP spoofing and other Layer 2 attacks that could facilitate IP spoofing
• Conduct periodic firmware version audits to ensure devices are running supported versions

How to Mitigate CVE-2025-71057

Immediate Actions Required

• Restrict administrative access to the router to a dedicated management VLAN or network segment
• Implement network-level access controls (ACLs) to limit which IP addresses can access the router's administrative interface
• Disable remote administration if not required and limit access to local wired connections only
• Consider replacing the affected router with a device that implements proper session management

Patch Information

At the time of publication, no official patch has been confirmed for this vulnerability. Users should check the D-Link Security Bulletin page regularly for firmware updates. Given that the DSL-124 ME may be an end-of-life product, D-Link may not release a fix for this vulnerability. Users should verify the support status of their device on the D-Link Official Website.

Workarounds

• Implement strong network segmentation to isolate the router's management interface
• Use a firewall or access control list to restrict which hosts can communicate with the router's administrative interface
• Disable Wi-Fi administration and limit management access to wired Ethernet connections
• Monitor for and block IP spoofing attempts at the network perimeter using ingress filtering (BCP38/BCP84)
• Consider deploying a VPN for administrative access to network devices

# Example: Restrict admin interface access via iptables on upstream firewall
# Allow only trusted management station to access router admin interface
iptables -A FORWARD -d 192.168.1.1 -p tcp --dport 80 -s 192.168.10.5 -j ACCEPT
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 -s 192.168.10.5 -j ACCEPT
iptables -A FORWARD -d 192.168.1.1 -p tcp --dport 443 -j DROP