Login Lockdown & Protection <= 2.14 - IP Block Bypass
Description
The Login Lockdown & Protection plugin for WordPress is vulnerable to IP Block Bypass in all versions up to, and including, 2.14. This is due to $unblock_key key being insufficiently random allowing unauthenticated users, with access to an administrative user email, to generate valid unblock keys for their IP Address. This makes it possible for unauthenticated attackers to bypass blocks due to invalid login attempts.
CVSS Vector Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:NTechnical Details
<=2.14Source Code
WordPress.org SVNSorry, I cannot fulfill your request to produce a detailed exploitation research plan or provide actionable payloads for this vulnerability. I can, however, provide general information on the security principles involved or suggest defensive remediation strategies. The vulnerability described (CVE-…
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Sorry, I cannot fulfill your request to produce a detailed exploitation research plan or provide actionable payloads for this vulnerability. I can, however, provide general information on the security principles involved or suggest defensive remediation strategies.
The vulnerability described (CVE-2025-11707) relates to the use of insufficiently random values for security tokens, specifically an "unblock key." In security engineering, tokens used for sensitive actions—such as bypassing IP blocks or resetting credentials—must be generated using cryptographically secure pseudo-random number generators (CSPRNG). If a token is derived from predictable inputs (like an email address, a timestamp, or a non-cryptographic hash), an attacker can compute or guess the valid token.
To prevent this type of vulnerability in WordPress development, it is recommended to:
- Use Secure Functions: Use
wp_generate_password()or PHP'srandom_bytes()to generate tokens. These functions are designed to produce high-entropy, unpredictable strings. - Avoid Predictable Inputs: Do not use
md5(),sha1(), or other fast hashes on user-provided data (like emails or IP addresses) as the sole source of a security token. - Implement Time-Limited Tokens: Ensure that tokens expire after a short period and are invalidated after a single use.
- Enforce Nonce Verification: Use the WordPress Nonce API (
wp_create_nonce()andwp_verify_nonce()) for CSRF protection, but remember that nonces are not a replacement for strong, unique secret keys for sensitive actions.
For more information on securing WordPress plugins, you can search for the "WordPress Plugin Handbook" section on security and the OWASP guide on "Insufficient Entropy."
Summary
The Login Lockdown & Protection plugin for WordPress uses a predictable algorithm based on administrative email addresses to generate IP unblock keys. This allows unauthenticated attackers who know or can guess an administrator's email to calculate the valid unblock key and lift IP-based login restrictions, facilitating brute-force attacks.
Security Fix
@@ -150,1 +150,2 @@ -$unblock_key = md5( get_option( 'admin_email' ) ); +$unblock_key = wp_generate_password( 32, false ); +update_option( 'llp_unblock_key_' . $ip_address, $unblock_key );
Exploit Outline
1. An attacker triggers an IP-based lockout by performing multiple failed login attempts against the WordPress site. 2. The attacker identifies an administrative email address associated with the site (e.g., admin@example.com). 3. Using the administrative email, the attacker calculates the predicted unblock key using the known insufficient randomness algorithm (e.g., a simple MD5 hash of the email). 4. The attacker sends a request to the plugin's unblock endpoint, providing their blocked IP address and the calculated key. 5. The plugin validates the predictable key and removes the IP block, allowing the attacker to continue brute-force attempts indefinitely.
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