CVE-2021-27885 in e107
Summary
by MITRE • 03/03/2021
usersettings.php in e107 through 2.3.0 lacks a certain e_TOKEN protection mechanism.
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Analysis
by VulDB Data Team • 12/16/2024
The vulnerability identified as CVE-2021-27885 affects the e107 content management system version 2.3.0 and earlier, specifically within the usersettings.php component. This issue represents a critical security flaw that undermines the integrity of user authentication and authorization mechanisms. The vulnerability stems from the absence of proper e_TOKEN protection within the user settings management interface, creating a significant attack surface for malicious actors seeking to exploit the system's security controls.
The technical flaw manifests as a missing token validation mechanism that should normally be implemented to prevent cross-site request forgery attacks. In the context of e107, the e_TOKEN serves as a cryptographic token that verifies the authenticity of requests made to the usersettings.php script. Without this protection, attackers can craft malicious requests that appear to originate from legitimate authenticated users, potentially allowing unauthorized modifications to user account settings, password changes, or privilege escalations. This vulnerability directly maps to CWE-352, which categorizes Cross-Site Request Forgery (CSRF) weaknesses in software applications. The absence of token validation creates an environment where attackers can manipulate user sessions and execute unauthorized actions within the CMS framework.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it can enable attackers to gain persistent access to user accounts and potentially compromise the entire CMS installation. Attackers can leverage this flaw to modify user permissions, reset passwords, or even create new administrator accounts, thereby establishing a foothold that could lead to complete system compromise. The vulnerability affects all users who have access to the usersettings.php endpoint, making it particularly dangerous in environments where multiple users interact with the CMS. From an attacker's perspective, this vulnerability aligns with ATT&CK technique T1078.004, which covers legitimate credentials and abuse of access tokens, as the missing token validation effectively allows unauthorized access to privileged functions.
Mitigation strategies for CVE-2021-27885 require immediate implementation of proper token validation mechanisms within the e107 codebase. System administrators should upgrade to e107 version 2.3.1 or later, where the missing e_TOKEN protection has been implemented. Additionally, organizations should consider implementing additional security controls such as web application firewalls that can detect and block suspicious requests to user settings endpoints. The fix should include generating and validating unique tokens for each user session, ensuring that all modifications to user settings require proper authentication tokens. Security monitoring should be enhanced to detect anomalous patterns in user setting modifications, and access controls should be reviewed to ensure least privilege principles are maintained. Regular security audits of CMS components should be conducted to identify similar token validation gaps that could expose the system to similar CSRF attacks.