CVE-2024-30255 is a medium-severity vulnerability affecting Envoy, a cloud-native, open-source edge and service proxy. The vulnerability resides in the HTTP/2 protocol stack in Envoy versions prior to 1.29.3, 1.28.2, 1.27.4, and 1.26.8. It allows attackers to exploit the system by sending a flood of CONTINUATION frames, leading to significant CPU exhaustion.
Specifically, the HTTP/2 codec in Envoy permits clients to send an unlimited number of CONTINUATION frames, even after exceeding the header map limits. This allows an attacker to effectively consume CPU resources, resulting in denial of service as the system struggles to process the excessive load.
The severity of this vulnerability is underscored by its CVSS score of 5.3, which falls into the medium category. Risk to organizations includes potential denial of service through CPU exhaustion, impacting service availability. The exploitation status indicates that a public proof of concept is available, which increases the urgency for organizations to address this issue.
Organizations should prioritize patching immediately by upgrading to the specified versions to mitigate the effects of this vulnerability. As a temporary workaround, disabling the HTTP/2 protocol for downstream connections is advised.
Vulnerability Details
Envoy is a cloud-native, open-source edge and service proxy, and the HTTP/2 protocol stack in versions prior to 1.29.3, 1.28.2, 1.27.4, and 1.26.8 is vulnerable to CPU exhaustion due to a flood of CONTINUATION frames. The vulnerability allows an attacker to send a sequence of CONTINUATION frames without the END_HEADERS bit set, causing excessive CPU utilization.
This vulnerability has been classified under CWE-390, indicating a communication protocol issue. The CVSS score of 5.3 reflects a medium severity level, highlighting the need for timely remediation.
Technical Analysis
The root cause of this vulnerability lies in the design of the HTTP/2 codec within Envoy. Attackers can exploit this design flaw by sending an unlimited number of CONTINUATION frames, which leads to CPU resource exhaustion as the proxy attempts to handle the flood of frames.
The attack vector for this vulnerability is network-based, meaning an attacker does not need physical access to the device to exploit it. The attack complexity is low, and no privileges or user interaction are required for the attack to be successful.
The impact on availability is classified as low, as the system can be rendered unavailable due to CPU exhaustion. Confidentiality and integrity impacts are not applicable in this scenario.
Risk & Impact Analysis
The real-world deployment risk associated with CVE-2024-30255 is significant, as organizations utilizing Envoy in production environments may experience service disruptions due to CPU exhaustion. This vulnerability can be particularly impactful in high-traffic scenarios where the proxy is expected to handle large volumes of requests.
The urgency assessment based on the CVSS score indicates that organizations should address this vulnerability in their priority patch cycle. Given the existence of public proof of concept exploits, organizations must act quickly to prevent potential denial of service attacks.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | Yes |
Public PoC | Yes |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
The affected versions of Envoy include all prior to 1.29.3, 1.28.2, 1.27.4, and 1.26.8. Organizations using these versions should upgrade immediately to mitigate the risks associated with this vulnerability.
Mitigation & Remediation
To remediate CVE-2024-30255, users should upgrade to one of the following patched versions of Envoy: 1.29.3, 1.28.2, 1.27.4, or 1.26.8. If immediate upgrading is not feasible, disabling the HTTP/2 protocol for downstream connections is recommended as a temporary workaround.
Furthermore, organizations should consider implementing network controls and monitoring solutions to detect unusual traffic patterns that may indicate exploitation attempts.
Continuous security testing can help identify vulnerabilities and ensure that systems are protected against potential exploitation.
Detection Guidance
Organizations should monitor logs for indicators of exploitation attempts, such as an unusual number of CONTINUATION frame requests. Behavioral anomalies in network traffic may also signal potential attacks. Implementing network signatures that detect these patterns can enhance defense mechanisms.
AppSecure Threat Intelligence Insight
The long-term significance of CVE-2024-30255 highlights a concerning trend regarding the exploitation of protocol vulnerabilities for denial of service attacks. Security teams must remain vigilant and proactive in addressing such vulnerabilities to safeguard their infrastructure.
This incident serves as a reminder of the importance of maintaining up-to-date software and conducting regular security assessments. Organizations can benefit from developing a comprehensive vulnerability management program to systematically address potential weaknesses.
For organizations looking to enhance their security posture, engaging in red teaming services can provide valuable insights into potential attack vectors and help in fortifying defenses.
Ultimately, the key takeaway is the need for continuous vigilance and improvement in security practices to mitigate risks from vulnerabilities like CVE-2024-30255.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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