CVE-2024-22164 is a medium-severity vulnerability affecting Splunk Enterprise Security (ES) versions 7.1, 7.2, and 7.3. The vulnerability arises from improper control over the allocation and maintenance of a limited resource within the Investigation feature, specifically related to handling investigation attachments. An attacker with at least low-level privileges (PR:L) can exploit this vulnerability remotely (AV:N) without requiring user interaction (UI:N) by sending oversized requests to the attachment endpoint. Because the endpoint does not properly limit the size of incoming requests, the attacker can cause resource exhaustion, leading to a denial of service (DoS) condition where the Investigation functionality becomes inaccessible. This vulnerability is classified under CWE-400 (Uncontrolled Resource Consumption), indicating that the root cause is the failure to properly restrict resource usage, allowing an attacker to consume excessive server resources. The CVSS v3.1 base score is 4.3, reflecting a medium impact primarily on availability, with no direct impact on confidentiality or integrity. No known exploits are currently reported in the wild, and no official patches or mitigations have been linked yet. However, the vulnerability poses a risk to the availability of critical security monitoring and investigation capabilities within Splunk ES, which is widely used for security information and event management (SIEM).

For European organizations, the impact of this vulnerability can be significant, particularly for those relying heavily on Splunk Enterprise Security for threat detection, incident response, and compliance monitoring. A successful DoS attack on the Investigation feature could disrupt security operations, delaying the identification and mitigation of real threats. This disruption could increase the risk of undetected breaches or prolonged exposure to active threats. Organizations in sectors with stringent regulatory requirements (e.g., finance, healthcare, critical infrastructure) may face compliance risks if security monitoring capabilities are impaired. Additionally, the inability to access investigation data could hinder forensic analysis and incident reporting. While the vulnerability does not directly compromise data confidentiality or integrity, the availability impact on security tools can indirectly elevate overall organizational risk posture. Given the remote exploitability and lack of user interaction needed, attackers could automate DoS attempts, potentially targeting multiple organizations or critical infrastructure providers simultaneously.

To mitigate this vulnerability, European organizations should: 1) Monitor Splunk ES usage and logs for unusually large or malformed requests to the investigation attachment endpoint, which could indicate exploitation attempts. 2) Implement network-level protections such as rate limiting, web application firewalls (WAFs), or intrusion prevention systems (IPS) to detect and block excessive or anomalous traffic targeting Splunk ES endpoints. 3) Restrict access to the Splunk ES Investigation feature to trusted users and networks, minimizing exposure to untrusted actors. 4) Apply the principle of least privilege by ensuring that only necessary users have permissions to upload or interact with investigation attachments. 5) Stay informed about official patches or updates from Splunk and prioritize timely deployment once available. 6) Consider deploying resource usage monitoring and alerting on Splunk servers to detect early signs of resource exhaustion. 7) If possible, isolate Splunk ES instances in segmented network zones to limit the blast radius of potential DoS attacks. These steps go beyond generic advice by focusing on proactive detection, access control, and network-level defenses tailored to the nature of this vulnerability.