Recent reports highlight a surge in MSSQL injection attacks, with threat actors exploiting vulnerabilities to execute remote commands and exfiltrate sensitive data. This article examines the mechanics of these attacks, real-world incidents, and defensive measures for security teams.
Executive Summary for Security Leaders
SQL injection (SQLi) remains a top attack vector, accounting for 60% of data breaches involving credential theft1. MSSQL-specific exploits, such as abuse of `xp_cmdshell`, enable attackers to escalate privileges to operating system-level access2. The average cost of a breach now exceeds $4.45 million3, underscoring the need for robust defenses.
Key Points:
– MSSQL’s extended procedures (e.g., `xp_cmdshell`) are frequently abused for RCE.
– Recent campaigns like Cl0p’s MOVEit exploitation demonstrate SQLi’s role in large-scale data theft.
– AI-generated polymorphic payloads are evading traditional WAFs4.
Technical Analysis of MSSQL Injection
Attackers typically follow a three-phase approach:
1. Reconnaissance: Tools like SQLMap or manual testing identify injectable parameters in web forms or APIs5.
2. Exploitation: Classic payloads (e.g., `’ OR 1=1–`) bypass authentication, while time-based techniques (e.g., `WAITFOR DELAY ‘0:0:5’`) confirm vulnerabilities silently.
3. Post-Exploitation: MSSQL’s `xp_cmdshell` allows execution of OS commands, as seen in FortiClient EMS (CVE-2023-48788)2.
Example of a Union-Based attack:
“`sql
SELECT * FROM products WHERE id=1 UNION SELECT 1,@@version,3,4–
“`
This extracts the database version while appearing as a legitimate query.
Case Studies: 2023-2024 Incidents
| Incident | Impact | Technique |
|---|---|---|
| MOVEit Transfer (CVE-2023-34362) | 60M+ records stolen | Second-order SQLi via file transfer workflows |
| FortiClient EMS | RCE via `xp_cmdshell` | Unauthenticated SQLi in admin panels |
Mitigation Strategies
1. Query Parameterization:
“`python
# Python (PyMSSQL)
cursor.execute(“SELECT * FROM users WHERE id = %d”, (user_id,))
“`
2. Database Hardening:
– Disable `xp_cmdshell`:
“`sql
EXEC sp_configure ‘show advanced options’, 1;
RECONFIGURE;
EXEC sp_configure ‘xp_cmdshell’, 0;
RECONFIGURE;
“`
3. WAF Rules:
– Block patterns like `UNION SELECT` and `EXEC xp_cmdshell` using ModSecurity.
Conclusion
MSSQL injection attacks continue to evolve, with attackers leveraging built-in features for lateral movement. Security teams should prioritize parameterized queries, regular vulnerability scanning, and least-privilege access controls.
