Introduction

SAML assertion rejected when clock difference between IdP and SP exceeds allowed skew. This guide provides step-by-step diagnosis and resolution.

Symptoms

Typical error output:

bash
Error: Identity operation failed
Check IAM logs for details
Verify configuration and credentials

Common Causes

  1. 1.Certificate or key expired or invalid
  2. 2.Clock synchronization issue between parties
  3. 3.Configuration mismatch between IdP and SP
  4. 4.Policy or rule blocking access

Step-by-Step Fix

Step 1: Check Current State

bash
# Check IAM logs
tail -f /var/log/auth.log
# Verify SAML/OIDC configuration
cat /etc/app/auth-config.yaml
# Test connectivity
curl -v https://idp.example.com/.well-known/openid-configuration

Step 2: Identify Root Cause

bash
# Check application logs
tail -f /var/log/application/auth.log
# Verify IdP connectivity
curl -v https://idp.example.com/status
# Check certificate
openssl s_client -connect idp.example.com:443

Step 3: Apply Primary Fix

```bash # Primary fix: Verify and update configuration # Check IdP metadata curl https://idp.example.com/metadata

# Update SP configuration # Verify certificate validity openssl x509 -in idp-cert.pem -text -noout

# Restart service systemctl restart application ```

Step 4: Apply Alternative Fix

bash
# Alternative: Check logs and debug
journalctl -u application -f
# Enable debug mode temporarily
export AUTH_DEBUG=true
# Test authentication flow
curl -v https://app.example.com/login

Step 5: Verify the Fix

bash
# Test authentication
curl -I https://app.example.com/protected
# Should return 200 or redirect to IdP correctly
# Check audit logs for successful login

Common Pitfalls

  • Not synchronizing clocks between IdP and SP
  • Using expired certificates
  • Incorrect entity IDs or audience URLs
  • Missing required attributes in SAML assertions

Best Practices

  • Implement certificate monitoring and rotation
  • Use NTP for clock synchronization
  • Test authentication flows regularly
  • Enable audit logging for all auth events
  • Authentication Failed
  • Authorization Denied
  • Session Timeout
  • SSO Error