CVE-2023-35945 is a high-severity vulnerability found in the Envoy Proxy, a cloud-native high-performance edge/middle/service proxy. This vulnerability allows the HTTP/2 codec to leak a header map and bookkeeping structures when it receives a `RST_STREAM` immediately followed by `GOAWAY` frames from an upstream server. This flaw can lead to denial of service through memory exhaustion.
The vulnerability has been assigned a CVSS score of 7.5, indicating a high severity level. It has significant implications for organizations utilizing Envoy Proxy, as it could lead to an exhaustion of memory resources, affecting availability. Organizations should prioritize patching immediately.
As of now, this vulnerability is not actively exploited, and no public proof of concept has been confirmed. The urgency for organizations to address this vulnerability stems from its potential impact on system stability.
Envoy Proxy versions 1.26.3, 1.25.8, 1.24.9, and 1.23.11 contain patches for this vulnerability. It is crucial for organizations to ensure they are running the updated versions to mitigate the risks associated with this vulnerability.
Vulnerability Details
The official description states that Envoy’s HTTP/2 codec may leak a header map and bookkeeping structures due to improper handling of the `GOAWAY` frames. The cleanup of pending requests skips the de-allocation of the bookkeeping structure and pending compressed header, leading to a memory leak, thus causing denial of service.
The CVSS v3.1 score for this vulnerability is 7.5, classified as high severity. The attack vector is network-based, with low attack complexity and no privileges required for exploitation. There is no impact on confidentiality or integrity, but there is a high impact on availability.
The affected products include Envoy versions prior to 1.23.11 and versions from 1.24.0 to 1.24.9, from 1.25.0 to 1.25.8, and from 1.26.0 to 1.26.3. The CWE classifications associated with this vulnerability include CWE-400 (Uncontrolled Resource Consumption) and CWE-459 (Use of Incompatible Encoding).
Technical Analysis
The root cause of this vulnerability lies in how Envoy handles incoming `GOAWAY` frames from upstream servers. When these frames are received, the cleanup of pending requests skips the necessary de-allocation of bookkeeping structures, which leads to a memory leak. As a result, this can cause the application to exhaust its memory resources and deny service to legitimate users.
The attack vector is network-based, allowing attackers to exploit this vulnerability without needing physical or local access to the system. The attack complexity is low, meaning that it can be executed without specialized knowledge or advanced tools. No user interaction is required, and there are no privileges needed to exploit the vulnerability.
The impacts of this vulnerability are focused on availability; while confidentiality and integrity are unaffected, the potential for denial of service means that organizations could experience significant disruptions in service availability due to memory exhaustion.
Risk & Impact Analysis
Risk to organizations includes the possibility of denial of service through memory exhaustion. If exploited, this could lead to significant downtime and impact the availability of services relying on Envoy Proxy. Organizations using affected versions should take this threat seriously and act quickly to implement the necessary patches.
The urgency for addressing this vulnerability is high due to its potential impact on service availability. Organizations should prioritize patching immediately to mitigate the risks associated with this vulnerability.
Considering the low complexity and network attack vector, even organizations with minimal security resources may find themselves vulnerable. It is crucial for security teams to stay informed about vulnerabilities like CVE-2023-35945 and ensure appropriate defenses are in place.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
The affected versions of Envoy Proxy include all versions prior to 1.23.11, as well as versions 1.24.0 to 1.24.9, 1.25.0 to 1.25.8, and 1.26.0 to 1.26.3. Organizations running these versions should upgrade to the respective patched versions immediately.
Mitigation & Remediation
To remediate this vulnerability, organizations should upgrade to the latest versions of Envoy Proxy: 1.26.3, 1.25.8, 1.24.9, or 1.23.11. In cases where immediate upgrading is not possible, organizations should implement strong network controls to limit exposure to affected systems and monitor for any unusual behavior.
For continuous monitoring and testing of application security, organizations may consider utilizing continuous penetration testing services to ensure vulnerabilities are identified and mitigated effectively.
Detection Guidance
Organizations should monitor logs for signs of unusual memory consumption and application crashes. Behavioral anomalies that could indicate exploitation include unexpected denial of service events. It is also recommended to keep an eye on network traffic patterns to detect any abnormal requests that might be related to this vulnerability.
AppSecure Threat Intelligence Insight
CVE-2023-35945 highlights the importance of timely updates and patching in maintaining the security of cloud-native applications. This vulnerability, while not yet exploited in the wild, underscores the need for proactive measures in vulnerability management. Security teams should conduct regular assessments to identify and mitigate potential threats.
For effective vulnerability management, organizations can refer to the vulnerability management program design to ensure comprehensive threat coverage.
Additionally, security teams should stay informed about emerging threats and trends in vulnerability exploitation, which can be facilitated by engaging in penetration testing methodology to evaluate their defenses against potential attacks.
Finally, organizations may consider implementing a dedicated API security testing framework to further strengthen their application security posture.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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