CVE-2017-16894 in Laravel
Summary
by MITRE
In Laravel framework through 5.5.21, remote attackers can obtain sensitive information (such as externally usable passwords) via a direct request for the /.env URI. The writeNewEnvironmentFileWith function in src/Illuminate/Foundation/Console/KeyGenerateCommand.php does not restrict the .env permissions.
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Analysis
by VulDB Data Team • 01/01/2025
The vulnerability identified as CVE-2017-16894 represents a critical information disclosure flaw within the Laravel web application framework affecting versions through 5.5.21. This vulnerability stems from improper file permission handling during the key generation process, creating a pathway for remote attackers to access sensitive configuration data that should remain protected. The flaw specifically resides in the writeNewEnvironmentFileWith function located within the KeyGenerateCommand.php file, which is responsible for managing the environment configuration file operations. When attackers make a direct request to the /.env URI endpoint, they can retrieve the contents of the environment file that contains critical credentials and configuration parameters.
The technical implementation of this vulnerability involves the improper handling of file permissions during the Laravel application's key generation workflow. The writeNewEnvironmentFileWith function fails to enforce proper access controls on the generated .env file, allowing unauthorized users to read the file contents through direct URI access. This occurs because the application does not validate or restrict access to the environment file, which typically contains database credentials, API keys, application secrets, and other sensitive information that should never be exposed to external parties. The flaw demonstrates a failure in the principle of least privilege and proper access control implementation, as the .env file should only be accessible to the web server process itself and authorized administrators.
From an operational perspective, this vulnerability poses significant risks to organizations using affected Laravel versions, as it enables attackers to obtain externally usable passwords and other sensitive credentials without requiring authentication or exploitation of other vulnerabilities. The impact extends beyond simple credential theft, as these exposed passwords often provide access to databases, third-party services, and other critical system components. The vulnerability can be exploited through simple HTTP requests, making it particularly dangerous as it requires minimal technical expertise to leverage. This type of information disclosure can lead to complete system compromise, data breaches, and unauthorized access to sensitive organizational resources.
The vulnerability aligns with CWE-200, which addresses improper exposure of sensitive information, and represents a classic example of insecure file handling and access control mechanisms. It also maps to ATT&CK technique T1552.001, which covers "Unsecured Credentials" through the exposure of stored credentials in configuration files. Organizations should immediately update to Laravel version 5.5.22 or later, where the fix addresses the improper file permission handling in the KeyGenerateCommand.php file. Additional mitigations include implementing proper web server configuration to prevent direct access to .env files, configuring access controls to restrict URI endpoints, and conducting comprehensive security reviews of all environment configuration files. The fix in the patched version ensures that the generated .env file receives appropriate permissions and access restrictions, preventing unauthorized retrieval of sensitive information through direct URI requests.