CVE-2018-18505 is a vulnerability that was discovered in 2018. It affects the mod_auth_mellon module in Apache httpd, which is used to implement single sign-on (SSO) functionality using the Security Assertion Markup Language (SAML). The vulnerability allows an attacker to bypass authentication checks and gain unauthorized access to protected resources. Specifically, it occurs when the SAML response is not properly verified during SSO authentication.
The vulnerability was assigned a critical severity rating by the National Vulnerability Database (NVD), and affected versions of Apache httpd were patched to address the issue. However, before the patch was released, attackers were able to exploit the vulnerability to gain access to protected resources on vulnerable systems. This led to several instances of unauthorized access and data breaches, as attackers were able to access sensitive information and perform unauthorized actions on compromised systems.
To mitigate the risk posed by CVE-2018-18505, organizations that use Apache httpd with mod_auth_mellon should ensure that they have applied the necessary patches and updates to their systems. Additionally, they should monitor their systems for signs of unauthorized access or other suspicious activity, and take appropriate action if any such activity is detected. Finally, they should consider implementing additional security measures, such as two-factor authentication or network segmentation, to further reduce the risk of exploitation.