CVE-2016-3952 in Web2py
Summary
by MITRE
web2py before 2.14.1, when using the standalone version, allows remote attackers to obtain environment variable values via a direct request to examples/template_examples/beautify. NOTE: this issue can be leveraged by remote attackers to gain administrative access.
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Analysis
by VulDB Data Team • 02/03/2023
The vulnerability identified as CVE-2016-3952 affects web2py versions prior to 2.14.1 when operating in standalone mode, representing a critical information disclosure flaw that exposes sensitive system environment variables to remote attackers. This vulnerability resides within the framework's template examples module, specifically at the path examples/template_examples/beautify, where direct requests can trigger the exposure of environment variable values. The flaw stems from inadequate input validation and access control mechanisms within the standalone web2py implementation, allowing unauthorized users to access internal system information that should remain protected. Such exposure of environment variables can include database connection strings, API keys, cryptographic secrets, and other sensitive configuration data that adversaries can leverage for further exploitation. The vulnerability operates through a simple HTTP request mechanism that bypasses normal authentication and authorization checks, making it particularly dangerous as it requires no prior access credentials to exploit.
The technical nature of this vulnerability aligns with CWE-200, which describes the exposure of sensitive information to an unauthorized actor, and represents a specific instance of information disclosure through improper access control. The flaw demonstrates characteristics of CWE-352, or Cross-Site Request Forgery, in that it allows unauthorized requests to access protected resources, though the actual attack vector is more direct in this case. From an operational perspective, this vulnerability creates a significant risk for systems running vulnerable web2py versions, as the exposure of environment variables can lead to complete system compromise. Attackers can use the leaked information to establish database connections, access administrative interfaces, or identify other vulnerable components within the system architecture. The standalone version of web2py is particularly susceptible because it often runs with elevated privileges and contains more exposed endpoints than the standard deployment configurations.
The impact of this vulnerability extends beyond simple information disclosure, as it provides attackers with the foundation for privilege escalation and administrative access to affected systems. When environment variables contain database credentials, application secrets, or other administrative tokens, adversaries can leverage this information to gain full control over the web application and underlying infrastructure. The vulnerability operates with minimal complexity, requiring only a direct HTTP request to the specific endpoint to trigger the information disclosure, making it highly exploitable in automated attack scenarios. This characteristic places the vulnerability in the ATT&CK framework under T1083, or File and Directory Discovery, as it enables attackers to discover sensitive system information, and potentially T1566, or Phishing, if the exposed credentials are used in subsequent attack phases. Organizations running vulnerable web2py installations face significant risk of data breaches, system compromise, and potential regulatory violations due to the exposure of sensitive operational data.
Mitigation strategies for CVE-2016-3952 involve immediate upgrading to web2py version 2.14.1 or later, which includes proper access controls and input validation for the affected endpoints. System administrators should also implement network segmentation to limit access to the standalone web2py installation, disable unnecessary example modules, and conduct thorough security audits of environment variable configurations. Additional protective measures include implementing web application firewalls to monitor and block requests to known vulnerable endpoints, conducting regular penetration testing to identify similar exposure issues, and establishing robust monitoring for unauthorized access attempts. The vulnerability underscores the importance of proper input validation and access control implementation in web frameworks, particularly in standalone configurations where default security settings may be insufficient. Organizations should also consider implementing principle of least privilege for web application deployments and regularly review their system configurations to prevent similar information disclosure vulnerabilities from emerging in other components of their infrastructure.