CVE-2019-11066 in LightOpenID
Summary
by MITRE
openid.php in LightOpenID through 1.3.1 allows SSRF via a crafted OpenID 2.0 assertion request using the HTTP GET method.
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Analysis
by VulDB Data Team • 09/15/2023
The vulnerability identified as CVE-2019-11066 affects LightOpenID versions through 1.3.1 and represents a server-side request forgery flaw that can be exploited through crafted OpenID 2.0 assertion requests. This issue specifically manifests when the openid.php component processes HTTP GET method requests containing maliciously constructed OpenID assertions. The vulnerability stems from insufficient input validation and sanitization of OpenID parameters, allowing attackers to manipulate the authentication flow and potentially redirect server requests to internal or external systems. Such a flaw creates significant security implications as it can enable unauthorized access to internal network resources that would normally be protected by firewalls or network segmentation. The vulnerability operates at the application layer and can be classified under CWE-918 as Server-Side Request Forgery, which is a well-documented weakness in web applications where user-controllable input is used to construct HTTP requests without proper validation or sanitization.
The technical exploitation of this vulnerability occurs when an attacker crafts a malicious OpenID 2.0 assertion containing a crafted URL in the OpenID endpoint parameter or related fields. When the vulnerable LightOpenID library processes this assertion through the HTTP GET method, it fails to properly validate or sanitize the input before using it in subsequent HTTP requests. This allows the attacker to potentially force the application to make HTTP requests to arbitrary URLs, including internal network addresses that should not be accessible from the internet. The flaw is particularly dangerous because OpenID authentication flows are often used in trusted environments where applications may have access to sensitive internal systems. This vulnerability can be mapped to ATT&CK technique T1190 which covers Proxying and tunneling through the use of compromised authentication systems to access internal resources.
The operational impact of CVE-2019-11066 extends beyond simple data exfiltration or unauthorized access to include potential internal network reconnaissance and lateral movement capabilities. An attacker could leverage this vulnerability to scan internal network services, access sensitive internal APIs, or even pivot to other systems within the network perimeter. The vulnerability affects applications that rely on LightOpenID for OpenID authentication and can lead to information disclosure, system compromise, or denial of service conditions. Organizations using vulnerable versions of LightOpenID should consider this vulnerability as a critical threat vector, particularly in environments where OpenID authentication is used for sensitive applications or services. The attack surface is broad as any application that accepts OpenID assertions and uses the vulnerable LightOpenID library is at risk, making this a widespread concern across various web applications and platforms.
Mitigation strategies for CVE-2019-11066 primarily focus on updating to the latest version of LightOpenID where the vulnerability has been addressed. Organizations should also implement strict input validation and sanitization for all OpenID parameters, particularly those related to endpoint URLs and assertion data. Network-level controls such as firewalls and web application firewalls should be configured to restrict outbound HTTP requests from authentication servers to prevent unauthorized access to internal systems. Additionally, implementing proper logging and monitoring of authentication flows can help detect anomalous behavior that may indicate exploitation attempts. Security teams should also consider implementing network segmentation and access controls to limit the potential impact if exploitation occurs, ensuring that even if an attacker successfully exploits this vulnerability, they cannot easily access sensitive internal resources. The vulnerability highlights the importance of proper input validation and the principle of least privilege in authentication systems, which aligns with security best practices outlined in various industry standards and frameworks including NIST SP 800-53 and ISO 27001.