CWE-454: External Initialization of Trusted Variables or Data Stores

What is External Initialization of Trusted Variables or Data Stores?

• Overview: This vulnerability occurs when a software system relies on critical internal variables or data stores that are initialized with inputs from outside its trust boundary, such as user inputs, which can be manipulated by attackers.

• Exploitation Methods:

• Attackers can provide malicious inputs to initialize trusted variables, influencing system behavior.
• Common attack patterns include injecting unexpected values or malformed data to control program logic.

• Security Impact:

• Direct consequences include unauthorized actions or system behavior based on manipulated variables.
• Potential cascading effects can lead to broader security breaches, data corruption, or unauthorized access.
• Business impact may involve data leaks, service disruptions, or reputational damage.

• Prevention Guidelines:

• Validate and sanitize all external inputs before using them to initialize critical variables.
• Implement strict access controls and input validation to ensure only authorized and validated data can affect critical variables.
• Use secure coding practices and frameworks that emphasize input validation and data integrity.
• Employ tools for static code analysis to identify and remediate potential vulnerabilities related to external variable initialization.

Corgea can automatically detect and fix External Initialization of Trusted Variables or Data Stores in your codebase. [Try Corgea free today](https://corgea.app).

Technical Details

Likelihood of Exploit: Not specified

Affected Languages: PHP, Not Language-Specific

Affected Technologies: Not specified

Vulnerable Code Example

PHP Example

// Vulnerable code: Initializing critical configuration variables from an external source
\$configData = json_decode(file_get_contents(\$_GET['config_url']), true); // External input used directly
\$databaseHost = \$configData['db_host']; // Potentially malicious data
\$databasePort = \$configData['db_port']; // Potentially malicious data

Explanation

In this example, the application initializes critical configuration variables using data from an external URL specified by the user. This can lead to serious vulnerabilities if an attacker supplies a malicious URL that returns harmful configuration data. The use of \$_GET['config_url'] allows an attacker to control where the configuration data is sourced from, potentially leading to unauthorized access or service disruption.

How to fix External Initialization of Trusted Variables or Data Stores?

To fix this vulnerability, ensure that critical configuration data is sourced from a secure and trusted location. Do not allow untrusted sources to dictate the configuration of your application. Use environment variables or secure, local configuration files that cannot be manipulated by external users. Additionally, validate and sanitize any data that is used to initialize critical variables.

Fixed Code Example

// Fixed code: Securely initializing configuration variables from a trusted source
\$trustedConfigFile = '/path/to/secure/config.json'; // Trusted, local file
\$configData = json_decode(file_get_contents(\$trustedConfigFile), true);

// Ensure the configuration is valid
if (json_last_error() === JSON_ERROR_NONE) {
    \$databaseHost = \$configData['db_host'];
    \$databasePort = \$configData['db_port'];
} else {
    // Handle configuration error
    die('Invalid configuration data.');
}

Explanation

In the fixed code example, the application retrieves configuration data from a local, secure file instead of an external source. This prevents untrusted actors from influencing critical application settings. The use of a predefined, trusted file path ensures that only authorized configuration data is used. Additionally, the code checks for JSON parsing errors to ensure the integrity of the configuration data. This approach secures the initialization process and protects the application from potential malicious attacks through configuration manipulation.