PHP 7 Vulnerable to Severe SQL Injection Flaw CVE-2022-31631

Executive Summary

Our security research team has discovered that CVE-2022-31631, a critical SQL injection vulnerability with a CVSS 3 score of 9.1, affects PHP 7 installations (on Windows and Linux) despite official advisories only mentioning PHP 8+ versions. This high-severity vulnerability allows attackers to bypass SQL sanitization in the PDO SQLite driver, potentially leading to database compromise. Particularly concerning is the timing of this disclosure, which occurred shortly after PHP 7 reached its End-of-Life (EOL) status, leaving many organizations vulnerable with no official patch available.

The Vulnerability Explained

CVE-2022-31631 is a serious security flaw that affects the PDO::quote() function when used with SQLite databases. When this function is supplied with an overly long string, an integer overflow occurs, causing the driver to incorrectly sanitize the data. This improper sanitization can lead to:

1. SQL injection vulnerabilities
2. Unauthorized access to database contents
3. Data manipulation or destruction
4. Potential for complete system compromise
5. Denial of service conditions

The criticality of this vulnerability is reflected in its CVSS score of 9.1, categorizing it as a “Critical” risk that demands immediate attention.

PHP 7: Vulnerable and Overlooked

The official advisory for CVE-2022-31631 only mentions these affected versions:

• PHP 8.0.x before 8.0.27
• PHP 8.1.x before 8.1.15
• PHP 8.2.x before 8.2.2

However, our comprehensive security testing has confirmed that PHP 7 series installations are also vulnerable to this SQL injection flaw. This creates a significant security gap for organizations still running PHP 7, as:

1. PHP 7 reached EOL status shortly before this vulnerability was disclosed
2. No official patches are available from PHP maintainers
3. The vulnerability affects a commonly used database functionality

Technical Details and Attack Scenario

The vulnerability occurs in the PDO SQLite driver’s quoting mechanism. When an application uses the PDO::quote() function to sanitize user input before including it in an SQL query (a common security practice), the function fails to properly handle extremely long strings.

Here’s a simplified explanation of how an attack might unfold:

1. An attacker identifies a web application using PHP with PDO SQLite
2. They supply an unusually long string to a vulnerable input field
3. The application passes this string to PDO::quote() for sanitization
4. Due to an integer overflow, the quoting function fails to properly escape the string
5. The malformed input results in SQL injection, allowing the attacker to execute arbitrary SQL commands

For example, a vulnerable application might contain code similar to:

// Vulnerable code pattern

$userInput = $_POST['user_input']; // Attacker-controlled input

$db = new PDO('sqlite:database.sqlite');

$safeInput = $db->quote($userInput); // Vulnerable when input is extremely long

$query = "SELECT * FROM users WHERE name = $safeInput";

In this scenario, if $userInput exceeds a certain length, the sanitization fails, potentially allowing SQL injection despite the developer’s attempt to use proper security practices.

Risk Amplification Factors

Several factors make this vulnerability particularly concerning:

1. High CVSS Score (9.1): Indicates a critical security issue with severe potential impact
2. Disclosure Timing: Released shortly after PHP 7 reached EOL, leaving users without an official path to remediation
3. Common Functionality: PDO is widely used for database operations in PHP applications
4. False Sense of Security: Developers believe they’re protecting against SQL injection by using PDO::quote()
5. Limited Awareness: Most security bulletins do not mention PHP 7’s vulnerability

Our Solution: Endless Lifecycle Support for PHP 7

Recognizing the critical nature of this vulnerability and its impact on PHP 7 users, our company provides:

1. Patched PHP 7 Packages: We’ve developed and thoroughly tested PHP 7 packages that fix the CVE-2022-31631 vulnerability
2. Cross-Platform Support: Our patched packages are available for both Windows and Linux environments
3. Comprehensive Security Coverage: Our extended support covers not just this vulnerability, but all known security issues affecting PHP 7

Recommended Mitigation Strategies

If your organization uses PHP 7 with PDO SQLite, we recommend the following immediate actions:

1. Apply Our Security Patches: Install our patched PHP 7 packages to protect against this vulnerability
2. Use Parameterized Queries: Switch to PDO prepared statements instead of relying on the quote() function:

$stmt = $db->prepare(“SELECT * FROM users WHERE name = ?”);$stmt->execute([$userInput]);

1. Implement Input Length Validation: Restrict the length of user inputs to reasonable values
2. Consider Database Permissions: Apply the principle of least privilege to database users

Conclusion

CVE-2022-31631 represents a perfect storm of security risk factors: a critical SQL injection vulnerability, disclosed just after PHP 7 reached EOL status, affecting a common security mechanism that developers rely on. Organizations running PHP 7 face a difficult choice between immediate migration (with potential compatibility issues) or continuing to run vulnerable systems.

Our extended PHP 7 support services provide a third option: continue running your PHP 7 applications with confidence, knowing that critical security vulnerabilities like CVE-2022-31631 have been addressed by our security patches.

Summary

Article Name

PHP 7 Vulnerable to Severe SQL Injection Flaw CVE-2022-31631

Description

CVE-2022-31631, a critical SQL injection vulnerability with a CVSS 3 score of 9.1, affects PHP 7 installations. Read More about our discover

Author

Joao Correia

Publisher Name

TuxCare

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