CVE-2020-28452 in com.softwaremill.akka-http-session
Summary
by MITRE • 01/20/2021
This affects the package com.softwaremill.akka-http-session:core_2.12 from 0 and before 0.6.1; all versions of package com.softwaremill.akka-http-session:core_2.11; the package com.softwaremill.akka-http-session:core_2.13 from 0 and before 0.6.1. CSRF protection can be bypassed by forging a request that contains the same value for both the X-XSRF-TOKEN header and the XSRF-TOKEN cookie value, as the check in randomTokenCsrfProtection only checks that the two values are equal and non-empty.
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Analysis
by VulDB Data Team • 02/18/2021
The vulnerability described in CVE-2020-28452 represents a critical security flaw in the akka-http-session library that affects multiple scala runtime versions including 2.11, 2.12, and 2.13. This issue specifically targets the cross-site request forgery protection mechanism implemented within the softwaremill akka-http-session core package. The vulnerability stems from a fundamental flaw in the random token csrf protection logic that fails to properly validate the authenticity of csrf tokens. The affected versions range from the initial release through all versions prior to 0.6.1, creating a substantial attack surface across various development environments and production systems that utilize this library for session management and csrf protection.
The technical root cause of this vulnerability lies in the implementation of the randomTokenCsrfProtection function which performs an inadequate validation check. The flaw occurs when the system accepts a forged request where both the X-XSRF-TOKEN header and the XSRF-TOKEN cookie contain identical values. This validation logic only verifies that the two values are equal and non-empty without ensuring that the token values are properly generated and authenticated. This oversight allows malicious actors to bypass the csrf protection mechanism by simply crafting a request with matching header and cookie values, effectively rendering the csrf protection worthless. The vulnerability is classified as a weakness in authorization and authentication controls, specifically relating to improper validation of security tokens.
The operational impact of this vulnerability is severe as it allows attackers to perform unauthorized actions on behalf of authenticated users within applications that rely on this library for csrf protection. An attacker could craft a malicious request that appears legitimate to the system because the token validation passes, enabling them to execute csrf attacks against vulnerable applications. This bypass affects the integrity of web applications that depend on csrf protection to prevent unauthorized requests from being processed. The vulnerability essentially creates a backdoor where any user session can be compromised through simple request manipulation, potentially leading to data theft, account takeovers, and unauthorized system modifications. The attack vector is particularly dangerous because it requires minimal sophistication to exploit and can affect any application using the vulnerable library version.
Organizations using affected versions of the akka-http-session library should immediately upgrade to version 0.6.1 or later to remediate this vulnerability. The fix should involve strengthening the csrf token validation logic to ensure that tokens are properly generated, authenticated, and that the system verifies the token's origin and legitimacy beyond simple value equality checks. Security teams should conduct thorough audits of their applications to identify all instances where this library is used and ensure proper implementation of csrf protection mechanisms. The vulnerability demonstrates the critical importance of proper token validation and authentication in web applications, aligning with common weakness enumerations such as CWE-346 and attack patterns documented in the mitre attack framework under credential access and privilege escalation categories. Additionally, organizations should implement comprehensive monitoring and logging to detect potential exploitation attempts and establish proper input validation controls to prevent similar issues in other security mechanisms.