CVE-2015-20121

What is this vulnerability?

CVE-2015-20121 is categorized as a critical SQL Injection flaw. Based on our vulnerability intelligence, this issue occurs when the application fails to securely handle untrusted data boundaries.

Next Click Ventures RealtyScript 4.0.2 contains SQL injection vulnerabilities that allow unauthenticated attackers to manipulate database queries by inject...

This architectural defect enables adversaries to bypass intended security controls, directly manipulating the application's execution state or data layer. Immediate strategic intervention is required.

Risk Assessment

Impact on Systems

✅ Data Exfiltration: Full compromise of the database schema, allowing extraction of all tables, user records, and PII.

✅ Authentication Bypass: Attackers can manipulate boolean logic in authentication queries to log in as administrators.

✅ Remote Code Execution: In severe configurations (e.g., xp_cmdshell in MSSQL), attackers can execute shell commands on the database underlying OS.

How to fix this issue?

Implement the following strategic mitigations immediately to eliminate the attack surface.

1. Prepared Statements Migrate entirely to parameterized queries (Prepared Statements) or an Object-Relational Mapper (ORM) to decouple code from data.

2. Input Validation Implement rigorous allow-list input validation for all sorting, filtering, and query parameters.

3. Principle of Least Privilege Ensure the database service account has the minimum necessary privileges, restricting DROP, TRUNCATE, and system execution commands.

Vulnerability Signature

// Example of a vulnerable Node.js/Express snippet

const category = req.query.category;

// DANGEROUS: Direct string concatenation of user input
const query = `SELECT * FROM products WHERE category = '$\{category\}'`;

db.query(query, (err, result) =\> \{
  if (err) throw err;
  console.log(result);
\});

// SECURED: Using parameterized queries avoids SQL injection
const category = req.query.category; // Ensure scope appropriately

// Safe: The database driver treats '?' strictly as data, not executable code
const query = 'SELECT * FROM products WHERE category = ?';

db.query(query, [category], (err, result) =\> \{
  if (err) throw err;
  console.log(result);
\});

References and Sources

• NVD — CVE-2015-20121
• MITRE — CVE-2015-20121
• CWE-89 — MITRE CWE
• CWE-89 Details
• Application Security Vulnerabilities
• AI Code Security Vulnerabilities
• PII and Secrets Exposure

Vulnerability Code Signature

Attack Data Flow

Vulnerable Code Pattern

# ❌ VULNERABLE: Direct string concatenation
def get_user(user_id):
    query = "SELECT * FROM users WHERE id = '" + user_id + "'"
    cursor.execute(query)  # Taint sink: unparameterized query
    return cursor.fetchone()

Secure Code Pattern

# ✅ SECURE: Parameterized query
def get_user(user_id):
    query = "SELECT * FROM users WHERE id = %s"
    cursor.execute(query, (user_id,))  # Sanitized binding
    return cursor.fetchone()

How Precogs Detects This

Precogs AI Analysis Engine traces data flow from HTTP request parameters through string concatenation directly into database execution sinks, identifying critical SQL injection vectors via Code Property Graph traversal.\n