CVE-2022-21655 is a high-severity vulnerability affecting Envoy Proxy, an open-source edge and service proxy designed for cloud-native applications. The vulnerability arises from an issue in the envoy common router, which can segfault if an internal redirect selects a route configured with direct response or redirect actions. This flaw can lead to a denial of service, thereby impacting the availability of services utilizing the Envoy Proxy.
With a CVSS score of 7.5, the vulnerability is classified as high severity. This classification indicates that the risk to organizations includes potential service disruptions due to the denial of service condition. Given that the exploitability score is noted as high, organizations should take this vulnerability seriously.
As of now, there are no confirmed public exploits for this vulnerability, and it is not included in the Known Exploited Vulnerabilities (KEV) catalog. However, organizations should prioritize patching to safeguard against potential exploitation, as attackers may leverage this vulnerability in the future.
Organizations should prioritize patching immediately to address this vulnerability and ensure the stability of their services.
Vulnerability Details
The official description of CVE-2022-21655 states: 'Envoy is an open source edge and service proxy, designed for cloud-native applications. The envoy common router will segfault if an internal redirect selects a route configured with direct response or redirect actions. This will result in a denial of service. As a workaround, turn off internal redirects if direct response entries are configured on the same listener.'
The CVSS score for this vulnerability is 7.5, indicating a high-severity level. The attack vector is network-based, with a low attack complexity, meaning that no special conditions are required to exploit it. Importantly, no privileges are required, and there is no user interaction necessary for an attack to occur. The impact on availability is high, which aligns with the potential for service disruption.
The vulnerability is classified under CWE-670, which refers to 'Access Control Issues'.
Technical Analysis
The root cause of CVE-2022-21655 lies in the internal routing mechanism of the Envoy Proxy. When an internal redirect is configured to select a route that contains direct response or redirect actions, the common router fails, leading to a segfault. This segfault occurs without requiring any special privileges or user interaction, making the attack vector particularly concerning.
The attack complexity is rated as low, indicating that the vulnerability could be exploited easily by attackers without intricate methods. There is no requirement for any specific privileges, which means that any user with access to the network could potentially trigger the vulnerability.
The impacts are significant, primarily affecting availability. Organizations relying on Envoy Proxy may experience service interruptions, affecting end-users and business operations.
Risk & Impact Analysis
The deployment of Envoy Proxy in production systems without appropriate mitigations exposes organizations to substantial risks. Given the high availability impact of this vulnerability, organizations could face significant service disruptions. As the attack complexity is low, the likelihood of exploit attempts is elevated, particularly as awareness of this vulnerability grows.
Organizations should assess their deployments of Envoy Proxy and ensure that any instances running vulnerable versions are patched. The urgency is underscored by the high CVSS score and the potential for significant operational impact due to service disruptions.
Given the current exploitability status, organizations should remain vigilant and monitor for potential signs of attempted exploitation. Regular vulnerability assessments will enhance the security posture against emerging threats.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
The affected versions of the Envoy Proxy include:
1. All versions prior to 1.18.6
2. Versions 1.19.0 to 1.19.2
3. Versions 1.20.0 to 1.20.1
4. Versions 1.21.0 to 1.21.0
Mitigation & Remediation
To mitigate the risks associated with CVE-2022-21655, organizations should implement the following measures:
1. Upgrade to the latest version of Envoy Proxy that addresses this vulnerability, specifically version 1.18.6 or later.
2. If immediate upgrading is not feasible, disable internal redirects if direct response entries are configured on the same listener as a temporary workaround.
3. Implement network controls to restrict access to the Envoy Proxy server, minimizing exposure to potential attacks.
4. Consider conducting an application security assessment to identify and remediate other potential vulnerabilities.
Organizations should validate remediation effectiveness through application security assessments to ensure ongoing security.
Detection Guidance
To detect potential exploitation attempts or impacts related to CVE-2022-21655, organizations should monitor for the following indicators:
1. Logs indicating segmentation faults or application crashes related to the Envoy Proxy.
2. Unusual patterns of internal redirects or unexpected behaviors in routing configurations.
3. Monitoring for service availability interruptions or degraded performance metrics.
AppSecure Threat Intelligence Insight
CVE-2022-21655 reflects a trend in increasing vulnerabilities within cloud-native application proxies. As organizations adopt microservices architectures, the security landscape continues to evolve, presenting new challenges for security teams.
This vulnerability illustrates the importance of maintaining updated configurations and understanding the implications of proxy settings. Security teams should regularly audit their configurations and conduct thorough penetration testing to identify potential weaknesses.
Organizations can enhance their security posture by implementing a robust vulnerability management program and adopting proactive security measures. Continuous monitoring and risk assessments should be integral to security strategies in addressing emerging threats.
For further insights on best practices in vulnerability management, organizations can refer to our vulnerability management program design guide.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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