CVE-2018-12540 in Vert.x
Summary
by MITRE
In version from 3.0.0 to 3.5.2 of Eclipse Vert.x, the CSRFHandler do not assert that the XSRF Cookie matches the returned XSRF header/form parameter. This allows replay attacks with previously issued tokens which are not expired yet.
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Analysis
by VulDB Data Team • 04/06/2023
The vulnerability identified as CVE-2018-12540 affects Eclipse Vert.x versions ranging from 3.0.0 through 3.5.2 and represents a critical security flaw in the Cross-Site Request Forgery protection mechanism. This issue resides within the CSRFHandler component which is designed to prevent malicious actors from executing unauthorized commands on behalf of authenticated users. The flaw specifically manifests in the handler's failure to validate that the XSRF cookie value matches the corresponding XSRF header or form parameter that is returned during the request processing cycle. This validation gap creates a significant security weakness that undermines the fundamental purpose of CSRF protection mechanisms.
The technical implementation flaw stems from the CSRFHandler's inadequate token validation logic where it accepts any valid token from the request without ensuring proper correlation between the cookie and the submitted token value. This allows attackers to capture a legitimate XSRF token from a valid session and reuse it in subsequent requests even after the original token has been consumed. The vulnerability operates under CWE-352 which categorizes Cross-Site Request Forgery attacks, and specifically aligns with the weakness of insufficient token validation. From an operational perspective, this flaw enables replay attacks that can persist for the duration of the token's validity period, potentially allowing unauthorized actions to be executed against authenticated users.
The impact of this vulnerability extends beyond simple session hijacking as it provides attackers with the capability to perform authenticated operations without proper authorization. When an attacker successfully exploits this weakness, they can execute transactions, modify data, or perform any action that the legitimate user is authorized to perform. The vulnerability's persistence is particularly concerning as it remains effective until the token expires naturally, providing attackers with an extended window of opportunity to conduct malicious activities. This type of attack pattern corresponds to techniques described in the ATT&CK framework under the 'Credential Access' and 'Initial Access' domains where attackers leverage valid credentials or tokens to gain unauthorized system access.
Organizations using affected versions of Eclipse Vert.x should immediately implement mitigations including upgrading to versions 3.5.3 or later where this vulnerability has been addressed through enhanced token validation mechanisms. Additionally, administrators should review their CSRF protection configurations to ensure proper cookie validation is enforced and consider implementing additional security layers such as SameSite cookie attributes or additional request verification mechanisms. The fix typically involves strengthening the CSRFHandler to enforce strict correlation between the cookie value and the submitted token parameter, ensuring that only tokens that match the session cookie are accepted for validation purposes.