CVE-2016-3954 in Web2py
Summary
by MITRE
web2py before 2.14.2 allows remote attackers to obtain the session_cookie_key value via a direct request to examples/simple_examples/status. NOTE: this issue can be leveraged by remote attackers to execute arbitrary code using CVE-2016-3957.
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Analysis
by VulDB Data Team • 02/03/2023
The vulnerability identified as CVE-2016-3954 affects web2py versions prior to 2.14.2 and represents a critical information disclosure flaw that exposes sensitive session management parameters. This vulnerability resides within the web2py framework's handling of direct requests to specific endpoints, specifically the examples/simple_examples/status path which inadvertently reveals the session_cookie_key value. The session_cookie_key serves as a critical cryptographic component in web2py's session management system, functioning as a secret key used to generate and validate session cookies. When this value becomes publicly accessible through an unauthenticated direct request, it fundamentally compromises the security of the entire session management infrastructure.
The technical exploitation of this vulnerability follows a well-defined pattern that aligns with CWE-200, which categorizes information exposure vulnerabilities. Attackers can simply make a direct HTTP request to the vulnerable endpoint to retrieve the session_cookie_key, which then provides them with the cryptographic key necessary to forge session cookies. This flaw directly enables session hijacking attacks where malicious actors can impersonate legitimate users within the web2py application. The vulnerability's impact extends beyond simple information disclosure as it serves as a foundational weakness that can be leveraged to execute more severe attacks, as noted in the CVE description that references CVE-2016-3957 for arbitrary code execution capabilities.
The operational implications of this vulnerability are severe for organizations relying on web2py applications, particularly those handling sensitive data or providing user authentication services. Once attackers obtain the session_cookie_key, they can generate valid session cookies for any user account, effectively bypassing authentication mechanisms and gaining unauthorized access to protected resources. This vulnerability affects the confidentiality, integrity, and availability of web2py applications by undermining the fundamental security assumptions of session management. The impact is particularly concerning in environments where web2py applications manage user accounts, administrative functions, or sensitive business data, as it creates an immediate path to privilege escalation and data compromise.
The exploitation of this vulnerability demonstrates the importance of proper input validation and access control mechanisms within web frameworks. Security practitioners should implement comprehensive monitoring and logging of direct requests to example endpoints, as these paths often serve as attack vectors for information disclosure vulnerabilities. Organizations should prioritize immediate patching of affected web2py installations to version 2.14.2 or later, where the vulnerability has been addressed through proper access controls and input sanitization. Additionally, implementing network segmentation and web application firewalls can provide additional layers of protection against unauthorized access to sensitive endpoints. The vulnerability also highlights the need for regular security assessments of web frameworks and their example applications, as these often contain unintended access points that can be exploited by threat actors. This issue aligns with ATT&CK technique T1213 which involves data from information repositories, and represents a clear example of how seemingly benign framework examples can become critical attack vectors when not properly secured.