CVE-2022-43562 is a vulnerability identified in Splunk Enterprise versions prior to 8.1.12, 8.2.9, and 9.0.2. The issue stems from improper input validation and escaping of the HTTP Host header, classified under CWE-20 (Improper Input Validation). This flaw allows a remote authenticated user to manipulate the Host header in HTTP requests, potentially enabling attacks such as cross-site scripting (XSS) and cache poisoning. Specifically, because the Host header is not properly sanitized, malicious input can be injected and reflected in responses or cached content, leading to client-side script execution or serving of poisoned cached data to users. The vulnerability requires the attacker to be authenticated, which limits exploitation to users with some level of access to the Splunk Enterprise system. The CVSS v3.1 base score is 3.0 (low severity), reflecting that the attack vector is network-based but requires high attack complexity and privileges, with no user interaction needed. The impact is limited to confidentiality (partial information disclosure through XSS), with no direct integrity or availability impact. No known exploits have been reported in the wild to date. The vulnerability affects multiple major versions of Splunk Enterprise, a widely used platform for searching, monitoring, and analyzing machine-generated data via a web interface. Given Splunk’s role in security operations and IT monitoring, exploitation could undermine trust in log data or lead to session hijacking or credential theft through XSS, impacting incident response and forensic investigations.

For European organizations, the impact of this vulnerability could be significant in environments where Splunk Enterprise is deployed for security monitoring, compliance, or operational intelligence. Successful exploitation could allow an authenticated insider or compromised user to execute malicious scripts in the context of the Splunk web interface, potentially leading to session hijacking, theft of sensitive information, or manipulation of displayed data. This could undermine the integrity of security monitoring and incident response processes, critical for compliance with regulations such as GDPR and NIS Directive. Cache poisoning could cause users to receive malicious or misleading content, further complicating trust in monitoring dashboards. Although the vulnerability does not directly affect system availability or integrity of backend data, the confidentiality impact and potential for lateral movement or privilege escalation within the monitoring environment pose risks. European organizations with strict data protection requirements and reliance on Splunk for security analytics should prioritize remediation to maintain operational security and regulatory compliance.

1. Upgrade Splunk Enterprise to versions 8.1.12, 8.2.9, 9.0.2 or later where the vulnerability is patched. 2. Implement strict access controls to limit authenticated user privileges, minimizing the risk from compromised or malicious insiders. 3. Employ web application firewalls (WAFs) with rules to detect and block suspicious Host header manipulations. 4. Conduct regular security audits and penetration testing focusing on web interface input validation. 5. Monitor Splunk logs for unusual activity or repeated malformed Host header requests indicative of exploitation attempts. 6. Educate administrators and users about the risks of XSS and cache poisoning in the context of Splunk dashboards. 7. Where possible, isolate Splunk management interfaces from general user networks to reduce exposure. 8. Review and harden caching mechanisms to prevent serving poisoned content. These steps go beyond generic patching advice by emphasizing access control, monitoring, and network segmentation tailored to Splunk environments.