CVE-2023-45288 is a high-severity vulnerability that allows an attacker to cause an HTTP/2 endpoint to read arbitrary amounts of header data. This is achieved by sending an excessive number of CONTINUATION frames, leading to potential denial-of-service (DoS) conditions. The vulnerability has a CVSS score of 7.5, indicating a significant risk to organizations that utilize HTTP/2.
The root cause of this vulnerability lies in the handling of HPACK state, which requires parsing all HEADERS and CONTINUATION frames on a connection. When a request's headers exceed the defined limit (MaxHeaderBytes), the excess headers are still parsed without memory allocation, potentially allowing an attacker to exploit the situation. This could result in the reading of arbitrary amounts of header data, even though the request itself will ultimately be rejected.
The risk to organizations includes not only the potential for service disruption due to excessive resource consumption but also the possibility of handling sensitive information inadvertently while processing headers. The urgency for defenders is high, and organizations are advised to prioritize patching this vulnerability immediately to mitigate possible exploitation.
Currently, there is a known proof of concept (PoC) available on GitHub, demonstrating the exploitation of this vulnerability. While it is not actively exploited in the wild, the existence of a PoC indicates potential risks that could be realized if left unaddressed.
Organizations should be vigilant in monitoring and applying any necessary updates to their HTTP/2 implementations to ensure protection against this vulnerability.
Vulnerability Details
The CVE-2023-45288 vulnerability allows an attacker to exploit an HTTP/2 endpoint by sending an excessive number of CONTINUATION frames, causing it to read arbitrary amounts of header data. This is due to the way HPACK state is maintained, which requires parsing all HEADERS and CONTINUATION frames in a connection. The vulnerability is classified as high severity with a CVSS score of 7.5, indicating a significant risk to organizations.
The vulnerability was published on April 4, 2024, and its attack vector is classified as NETWORK with low attack complexity and no privileges required for exploitation. This means that attackers can exploit this vulnerability without needing any special access rights, making it easier for them to initiate an attack.
The potential impacts of this vulnerability include a high availability impact, while confidentiality and integrity impacts are rated as none. This means that while the service may become unavailable, sensitive data is not at risk of being leaked or altered through this specific vulnerability.
Technical Analysis
The root cause of CVE-2023-45288 stems from the improper handling of HTTP/2 header frames. When an excessive number of CONTINUATION frames are sent, the HTTP/2 endpoint must parse and process these frames, leading to resource exhaustion. Even though excess headers beyond MaxHeaderBytes do not allocate memory for storage, they still consume processing resources.
This vulnerability has a low attack complexity, which means that it can be exploited easily by attackers. There is no need for user interaction, and the attack can be initiated over a network, making it a potent vector for denial-of-service attacks.
In terms of impact, the primary concern is availability. Attackers leveraging this vulnerability may cause significant disruptions in service by exhausting the resources of the HTTP/2 implementation, which can lead to outages or degraded performance for legitimate users.
Risk & Impact Analysis
Real-world deployment of HTTP/2 services without addressing CVE-2023-45288 poses a substantial risk. The ability for attackers to flood a server with excessive header frames can lead to service outages, impacting organizations' operations and customer satisfaction. The availability impact is assessed as high, emphasizing the urgency for organizations to act.
In the context of the CVSS score of 7.5, organizations should address this vulnerability in their priority patch cycle. The potential for service disruption and the existence of a public PoC increase the urgency for remediation. Organizations are advised to implement the necessary patches and monitor their systems closely following the updates.
Signal | Status |
|---|---|
Known Exploit | Yes |
Public PoC | Yes |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
Specific version information is currently not available. Organizations should assume all versions of HTTP/2 implementations that do not have the latest patches applied are vulnerable. It is critical to update to the latest version as soon as patches are released to mitigate this vulnerability.
Mitigation & Remediation
Organizations should prioritize applying patches provided by their HTTP/2 implementation vendors. The fix for this vulnerability sets a limit on the amount of excess header frames that will be processed before a connection is closed. Regular updates and monitoring for patches are essential practices.
In addition to patching, organizations are encouraged to implement network controls that limit the size and number of HTTP/2 headers that can be sent to their services. Monitoring for unusual patterns in HTTP traffic can also help in detecting potential exploitation attempts.
For further assistance and testing of your implementation against this vulnerability, consider engaging in penetration testing services.
Detection Guidance
Organizations should monitor their HTTP/2 endpoints for any signs of unusual header activity. Key indicators include a sudden increase in the number of CONTINUATION frames and unusually large header sizes. Implementing logging for HTTP requests can assist in identifying these anomalies.
Behavioral anomalies such as repeated connection resets or service unavailability may indicate exploitation attempts. Additionally, monitoring for patterns of excessive resource utilization can help in identifying potential denial-of-service attacks.
AppSecure Threat Intelligence Insight
CVE-2023-45288 highlights the importance of robust input validation and resource management in network protocols. The vulnerability illustrates how seemingly minor issues, such as header size limitations, can lead to significant service disruptions. Security teams should take this as a lesson to regularly review and audit their configurations to ensure they align with best practices.
This incident also emphasizes the need for continuous monitoring and adaptation of security measures to protect against evolving threats. Organizations should engage in regular security assessments and consider leveraging penetration testing methodologies to identify and remediate potential vulnerabilities proactively.
Finally, organizations are encouraged to remain engaged with the security community for information on emerging vulnerabilities and threats. Following updates from reliable sources is crucial for staying informed about potential risks.
For more insights on vulnerability management, consider referring to our guide on vulnerability management programs.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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