CVE-2021-35233 in Kiwi Syslog Server
Summary
by MITRE • 10/27/2021
The HTTP TRACK & TRACE methods were enabled in Kiwi Syslog Server 9.7.1 and earlier. These methods are intended for diagnostic purposes only. If enabled, the web server will respond to requests that use these methods by returning exact HTTP request that was received in the response to the client. This may lead to the disclosure of sensitive information such as internal authentication headers appended by reverse proxies.
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Analysis
by VulDB Data Team • 10/31/2021
The vulnerability identified as CVE-2021-35233 affects Kiwi Syslog Server versions 9.7.1 and earlier, where the HTTP TRACK and TRACE methods remain enabled by default. These HTTP methods are explicitly designed for diagnostic purposes within web server environments and are typically disabled in production systems due to their potential security implications. The TRACK method is used to trace the path of a request through a network, while the TRACE method allows clients to see exactly what the server receives, including any headers that may have been added or modified during transit.
When these methods are enabled, the web server responds to requests using these methods by echoing back the complete HTTP request that was received, including all headers and potentially sensitive information. This behavior creates a significant information disclosure risk because reverse proxies often append authentication headers to requests as they pass through the network infrastructure. These headers may contain session tokens, API keys, or other authentication credentials that should remain confidential between systems.
The security implications of this vulnerability align with CWE-200, which addresses "Information Exposure," and represent a clear violation of the principle of least privilege in web server configuration. Attackers could exploit this vulnerability by sending malicious TRACE requests to the affected server, potentially capturing authentication tokens and other sensitive data that flows through reverse proxy configurations. This type of attack falls under the ATT&CK technique T1071.004 for Application Layer Protocol: DNS and T1566.001 for Phishing: Spearphishing Attachment, as it enables attackers to harvest credentials through information disclosure.
The operational impact extends beyond simple information disclosure, as the vulnerability could facilitate more sophisticated attacks including session hijacking, credential theft, and privilege escalation within network environments where reverse proxies are used for authentication. Organizations using Kiwi Syslog Server in production environments should immediately disable the TRACK and TRACE methods through proper web server configuration. The recommended mitigation involves configuring the server to explicitly disable these methods, typically through web server configuration files or security headers, ensuring that only necessary HTTP methods are enabled for the server's operational requirements.
Security professionals should also implement network monitoring to detect and alert on suspicious TRACE and TRACK method usage, as these requests are rarely legitimate in production environments. The vulnerability demonstrates the importance of following secure configuration practices for web servers and the necessity of regularly reviewing and updating security settings to prevent unintended functionality that could compromise system integrity and data confidentiality. Organizations should also consider implementing web application firewalls and security monitoring solutions that can detect and block suspicious HTTP method usage patterns that may indicate exploitation attempts.