Overview
Spring Framework is a comprehensive Java framework for building enterprise-level applications. It provides a powerful, flexible programming model that simplifies the development of web applications by allowing you to use Java as your primary language while offering a variety of tools to manage application configuration, data access, and security.
A Denial of Service (DoS) vulnerability (CVE-2024-38809) has been identified in Spring Framework in applications that parse ETags from If-Match or If-None-Match request headers are. Users of affected versions should upgrade to the corresponding fixed version. For older, unsupported versions, enforcing a size limit on If-Match and If-None-Match headers—e.g., through a filter—can help mitigate the risk.
The Open Web Application Security Project (OWASP) explains that DoS attacks aim to make a service “unavailable for the purpose it was designed.” In this case, carefully crafted ETags can trigger excessive computation, preventing other users from accessing the system in a timely manner—or at all.
This issue affects multiple versions of Spring Framework.
Details
Module Info
- Product: Spring Framework
- Affected packages: spring-web
- Affected Versions: >=4.3.0 <=4.3.30, >=5.3.0 <5.3.38, >=6.0.0 <6.0.23, >=6.1.0 <6.1.12
- GitHub repository: https://github.com/spring-projects/spring-framework/tree/main/spring-web
- Published package: https://mvnrepository.com/artifact/org.springframework/spring-web
- Package manager: Maven
- Fixed In: NES for Spring Framework v4.3.32 and v5.3.44
Vulnerability Info
This medium-severity vulnerability is found in the spring-web.jar module of the Spring Framework.
The flaw affects applications that parse ETags in HTTP headers, specifically those using the If-Match or If-None-Match headers. Exploiting this vulnerability allows an attacker to disrupt services by sending conditional HTTP requests that the application cannot process efficiently, leading to resource exhaustion and impacting availability.
For users on unsupported versions who cannot upgrade, a workaround is to enforce size limits on the affected headers, which can be implemented through a filter.
Steps To Reproduce
You can simulate a Denial of Service (DoS) attack through this vulnerability by crafting an HTTP request with an oversized or overly complex If-Match or If-None-Match header. Since this flaw specifically impacts Spring applications that process ETags, the proof-of-concept (PoC) would aim to overload the application's header-processing logic.
A malicious request could exploit the regular expression (regex) matching logic used during header processing. By sending a large number of repeated requests with the header set to a long sequence of *, the application interprets it as an array of elements, consuming significantly more CPU and memory than intended, ultimately leading to resource exhaustion.
Credits
- Seokchan Yoon
Mitigation
Spring Framework 4.3.x is no longer community-supported. The community support version will not receive any updates to address this issue. For more information, see here.
Users of the affected components should apply one of the following mitigations:
- Upgrade to a corrected version.
- Leverage a commercial support partner like HeroDevs for post-EOL security support.
