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Mohammad Waseem
Mohammad Waseem

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Leveraging Open Source Tools to Validate Email Flows with SQL

#security #sql #email

Ensuring the integrity and proper routing of email flows is a critical aspect of organizational security and operational efficiency. A security researcher focusing on validating email flows can utilize open source tools combined with SQL queries to audit, analyze, and verify email routing and handling processes effectively.

Understanding the Challenge:
Email systems are complex, involving multiple layers such as sending, receipt, forwarding, filtering, and storage. Validating that emails are correctly routed and processed requires examining logs, message headers, and flow data sometimes stored in relational databases or logs retrievable via open source tools.

Open Source Tools for Email Analysis:
Tools such as MailHog, MailDev, or open source SIEM solutions like ELK stack (Elasticsearch, Logstash, Kibana) provide environments to capture and analyze email traffic. Additionally, email headers contain valuable metadata, enabling validation of email provenance and routing.

Using SQL for Validation:
Many organizations store email flow logs or metadata in relational databases. SQL becomes a powerful language to query these datasets for anomalies, missing data, or misrouted messages.

For example, suppose you have a table email_logs with the following relevant columns:

  • message_id
  • sender
  • recipient
  • timestamp
  • status
  • header

You can run SQL queries to validate email flow integrity:

-- Check for emails that lack proper routing headers
SELECT message_id, sender, recipient, header
FROM email_logs
WHERE header NOT LIKE '%Received:%'
  AND status = 'delivered';
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This query helps identify emails that arrived without proper routing information, which could signal spoofing or misconfiguration.

-- Verify if emails sent from a specific connector reach intended recipients
SELECT message_id, sender, recipient, timestamp
FROM email_logs
WHERE sender = 'alerts@company.com' AND recipient LIKE '%@clientdomain.com%'
ORDER BY timestamp DESC;
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This ensures that crucial email flow, such as alerts or notifications, reach the correct endpoints.

Automating Validation with Scripts:
By combining SQL queries with scripting—using languages like Python, combining libraries such as sqlite3, psycopg2, or SQLAlchemy—researchers can automate validation routines. For example, periodically querying the database for missing or suspicious data, then generating reports or alerts.

Addressing Common Flow Issues:

  • Spoofing: Detect messages with inconsistent headers, missing authentication results, or unusual sender addresses.
  • Misdirection: Verify if email flow logs show unexpected routing paths or delays.
  • Delivery Failures: Identify any non-delivered messages and analyze failure reasons. 
-- Find undelivered emails within a timeframe
SELECT message_id, sender, recipient, timestamp
FROM email_logs
WHERE status != 'delivered'
  AND timestamp > NOW() - INTERVAL '7 days';
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Conclusion:
By combining the capabilities of open source email tools with the power of SQL queries, a security researcher can develop a comprehensive framework for validating email flows. This method not only detects anomalies or malpractices but also helps organizations maintain trustworthy communication channels by providing transparency and early-warning signs of potential issues.

Adopting such practices enhances security posture, streamlines operational oversight, and builds resilient email infrastructure.

References:

This approach exemplifies how open source tools and SQL can be harnessed by security researchers to address complex email validation challenges systematically and efficiently.

🛠️ QA Tip

To test this safely without using real user data, I use TempoMail USA.

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