Password reset tokens are critical for account security, but poor implementation can turn them into backdoors. Here are two common vulnerabilities in password reset functions:
1. The Password Reset Token Does Not Expire
If a token has no expiration, attackers can reuse it indefinitely. For example, a token generated a week ago might still work, giving attackers unlimited time to exploit it.
2. The Password Reset Token Is Not Invalidated
Even after a user resets their password, the old token remains valid. Attackers can reuse it to override the new password, maintaining persistent access.
Once a vulnerable reset URL is generated, it can be found in:
– Proxy logs
– Browser caches
– Referrer headers
– Email leaks
You Should Know: How to Secure Password Reset Tokens
1. Implement Token Expiration
Tokens should expire after a short period (e.g., 15-30 minutes). Here’s how to enforce this in code:
Python (Flask Example)
from datetime import datetime, timedelta from itsdangerous import URLSafeTimedSerializer SECRET_KEY = "your-secret-key" serializer = URLSafeTimedSerializer(SECRET_KEY) def generate_reset_token(email): return serializer.dumps(email, salt='password-reset-salt') def verify_reset_token(token, max_age=1800): 30 minutes expiration try: email = serializer.loads(token, salt='password-reset-salt', max_age=max_age) return email except: return None
PHP Example
$token = bin2hex(random_bytes(32));
$expiry = date("Y-m-d H:i:s", time() + 1800); // 30 minutes expiry
// Store in database
$stmt = $pdo->prepare("INSERT INTO password_resets (email, token, expires_at) VALUES (?, ?, ?)");
$stmt->execute([$email, $token, $expiry]);
2. Invalidate Tokens After Use
Once a password is reset, delete or mark the token as used.
SQL Command
DELETE FROM password_resets WHERE token = '[bash]';
3. One-Time Use Tokens
Ensure tokens can only be used once.
Node.js Example
const usedTokens = new Set();
function isTokenUsed(token) {
return usedTokens.has(token);
}
function markTokenAsUsed(token) {
usedTokens.add(token);
}
4. Rate Limiting Password Resets
Prevent brute-force attacks by limiting reset attempts.
Linux (iptables Rate Limit)
iptables -A INPUT -p tcp --dport 80 -m state --state NEW -m recent --set iptables -A INPUT -p tcp --dport 80 -m state --state NEW -m recent --update --seconds 60 --hitcount 10 -j DROP
5. Logging & Monitoring
Track reset attempts for suspicious activity.
Linux (Log Analysis with grep)
grep "password_reset" /var/log/auth.log | awk '{print $1, $2, $3, $6, $9}'
What Undercode Say
Password reset tokens are a common attack vector. Weak implementations allow attackers to hijack accounts indefinitely. Best practices include:
– Short-lived tokens (15-30 minutes)
– One-time use (invalidate after reset)
– Rate limiting (prevent brute force)
– Secure storage (avoid logs/caches)
– Monitoring (detect abuse)
Expected Output:
A secure password reset system that prevents token reuse and brute-force attacks.
Prediction:
As authentication systems evolve, we’ll see more AI-driven anomaly detection to flag suspicious password reset attempts in real-time.
Relevant Course:
Weekly Pentest Tips & Tricks (130+ Lessons) (Replace with actual URL if available)
References:
Reported By: Aaandrei %F0%9D%90%96%F0%9D%90%A1%F0%9D%90%9E%F0%9D%90%A7 – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
