CVE-2022-31394 in Hyper
Summary
by MITRE • 02/21/2023
Hyperium Hyper before 0.14.19 does not allow for customization of the max_header_list_size method in the H2 third-party software, allowing attackers to perform HTTP2 attacks.
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Analysis
by VulDB Data Team • 03/23/2023
The vulnerability identified as CVE-2022-31394 affects Hyperium Hyper library versions prior to 0.14.19, specifically targeting the HTTP/2 implementation within this Rust-based web framework. This issue stems from the library's inability to properly configure the max_header_list_size parameter in the H2 third-party software component, creating a potential attack vector for malicious actors seeking to exploit HTTP/2 protocol weaknesses. The vulnerability exists at the protocol implementation level where the library fails to expose or adequately control the maximum header list size that can be processed during HTTP/2 communication, leaving systems susceptible to resource exhaustion attacks.
The technical flaw manifests in the HTTP/2 handling mechanism where the H2 crate's default maximum header list size configuration is not customizable through the Hyperium Hyper interface. This limitation allows attackers to send HTTP/2 requests containing excessive header data that exceeds the default limits, potentially causing memory exhaustion or denial of service conditions. The vulnerability operates by leveraging the HTTP/2 protocol's header compression and framing mechanisms to craft malicious requests that consume disproportionate system resources, effectively enabling resource exhaustion attacks against services using affected Hyperium Hyper versions. The root cause aligns with CWE-400, specifically targeting resource exhaustion vulnerabilities in network protocols.
From an operational perspective, this vulnerability presents significant risks to web services and applications that rely on Hyperium Hyper for HTTP/2 communication, particularly those handling high volumes of requests or operating in environments where resource constraints are critical. Attackers can exploit this weakness to perform HTTP/2 specific attacks such as header flood attacks or connection exhaustion, potentially leading to service disruption, resource starvation, or even system crashes. The impact extends beyond simple denial of service as the vulnerability could enable more sophisticated attacks depending on the application's resource management and error handling capabilities. This vulnerability particularly affects systems that do not implement proper rate limiting or connection monitoring mechanisms to detect and mitigate such attacks.
The mitigation strategy involves upgrading to Hyperium Hyper version 0.14.19 or later, which includes proper support for configuring the max_header_list_size parameter. Organizations should also implement network-level protections such as rate limiting, connection pooling restrictions, and monitoring for unusual header sizes in HTTP/2 traffic. Additionally, security teams should consider implementing intrusion detection systems that can identify patterns consistent with HTTP/2 header flood attacks and establish proper logging mechanisms to track and analyze such suspicious activities. The remediation process should include thorough testing of upgraded systems to ensure that the new configuration options work correctly without introducing compatibility issues in existing applications. This vulnerability demonstrates the importance of proper protocol parameter exposure and the need for comprehensive security testing of third-party dependencies in web frameworks.