CVE-2020-12480 in Play Framework
Summary
by MITRE
In Play Framework 2.6.0 through 2.8.1, the CSRF filter can be bypassed by making CORS simple requests with content types that contain parameters that can't be parsed.
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Analysis
by VulDB Data Team • 08/18/2020
The vulnerability identified as CVE-2020-12480 represents a critical security flaw in the Play Framework that affects versions between 2.6.0 and 2.8.1. This issue specifically targets the Cross-Site Request Forgery (CSRF) protection mechanism that is fundamental to web application security. The Play Framework's CSRF filter serves as a crucial defense against malicious requests that attempt to exploit user sessions and perform unauthorized actions on behalf of authenticated users. The vulnerability arises from an insufficient validation mechanism that fails to properly handle certain content type parameters in Cross-Origin Resource Sharing (CORS) simple requests, creating an exploitable gap in the framework's security posture.
The technical flaw stems from how the CSRF filter processes content types in CORS simple requests where content types contain parameters that cannot be parsed correctly. When a client makes a CORS simple request with a content type that includes parameters, the framework's parsing logic fails to properly validate these parameters, allowing the CSRF protection to be circumvented. This occurs because the framework's implementation does not adequately sanitize or validate content type parameters before determining whether a request should be subject to CSRF protection. The vulnerability specifically leverages the fact that certain content types with parameters can bypass the filter's logic, creating a condition where legitimate requests are not properly authenticated while potentially malicious requests can proceed without CSRF validation.
The operational impact of this vulnerability is significant as it allows attackers to bypass the CSRF protection mechanism that is designed to prevent unauthorized actions from being executed on behalf of authenticated users. This vulnerability can be exploited in scenarios where an attacker can trick a victim into making a CORS simple request with a specially crafted content type that contains parameters. The attack vector typically involves social engineering or exploitation of other vulnerabilities that allow the attacker to inject malicious requests into the victim's browser context. Successful exploitation could enable attackers to perform actions that would normally require CSRF protection, potentially leading to unauthorized transactions, data modification, or privilege escalation within applications that rely on Play Framework's CSRF protection.
Organizations utilizing Play Framework versions within the affected range face substantial risk from this vulnerability, as it directly undermines the security controls that protect against CSRF attacks. The vulnerability aligns with CWE-346, which addresses "Origin Validation Error" in security contexts where applications fail to properly validate the origin of requests. Additionally, this issue maps to ATT&CK technique T1203, which involves "Exploitation for Client Execution" where attackers leverage application vulnerabilities to execute malicious code or bypass security controls. The vulnerability also reflects broader concerns about input validation and parameter handling in web applications, as highlighted in CWE-20, which addresses "Improper Input Validation" in security contexts where applications fail to properly validate user-supplied data.
Mitigation strategies for CVE-2020-12480 primarily involve upgrading to Play Framework versions that have addressed this vulnerability, specifically versions beyond 2.8.1 where the CSRF filter has been properly enhanced to handle content type parameters. Organizations should also implement additional defensive measures including enhanced input validation, stricter content type handling, and comprehensive security testing of CORS configurations. Security teams should conduct thorough vulnerability assessments to identify applications running affected versions and ensure proper patching procedures are followed. The fix typically involves strengthening the CSRF filter's content type parsing logic to properly handle parameters within content types, ensuring that all content types are validated against a whitelist of acceptable values before CSRF protection is bypassed or applied. Regular security monitoring and automated vulnerability scanning should be implemented to detect similar issues in other web applications and frameworks that may be susceptible to similar parameter parsing vulnerabilities.