CVE-2022-43572 is a denial-of-service (DoS) vulnerability classified under CWE-400 (Uncontrolled Resource Consumption) affecting Splunk Enterprise versions prior to 8.2.9, 8.1.12, and 9.0.2. The vulnerability arises when a specially crafted malformed file is sent to an indexer via the Splunk-to-Splunk (S2S) or HTTP Event Collector (HEC) protocols. These protocols are commonly used for data ingestion and forwarding within Splunk environments. The malformed file triggers resource exhaustion or blockage on the indexer, causing it to stop processing further indexing operations. This effectively results in a denial-of-service condition, impairing the availability of the Splunk service for log ingestion and analysis. The vulnerability does not impact confidentiality or integrity directly but severely affects availability, which is critical for security monitoring and operational visibility. Exploitation requires no authentication or user interaction and can be performed remotely over the network, increasing the attack surface. The CVSS v3.1 base score is 7.5 (high severity) with vector AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H, indicating network attack vector, low attack complexity, no privileges or user interaction required, unchanged scope, no confidentiality or integrity impact, but high impact on availability. No known exploits in the wild have been reported as of the publication date (November 2022).

For European organizations, the impact of this vulnerability can be significant, especially for those relying heavily on Splunk Enterprise for security information and event management (SIEM), operational intelligence, and compliance monitoring. A successful DoS attack could disrupt log ingestion and indexing, leading to gaps in security monitoring and delayed detection of other threats. This could increase the risk of undetected intrusions or compliance violations. Critical infrastructure operators, financial institutions, and large enterprises with stringent monitoring requirements are particularly at risk. The disruption of Splunk services may also affect incident response capabilities and operational decision-making. Given the remote and unauthenticated nature of the exploit, attackers could leverage this vulnerability to cause widespread service outages or as a diversion tactic during multi-stage attacks. The absence of known exploits reduces immediate risk but does not eliminate the threat, especially as attackers may develop exploits over time.

Upgrade Splunk Enterprise to versions 8.2.9, 8.1.12, 9.0.2 or later where the vulnerability is patched. Implement network-level filtering to restrict access to Splunk indexers, limiting S2S and HEC protocol traffic to trusted sources only. Monitor network traffic for anomalous or malformed packets targeting S2S and HEC endpoints to detect potential exploitation attempts. Enforce strict input validation and rate limiting on data ingestion endpoints to reduce the risk of resource exhaustion. Segment Splunk infrastructure within secure network zones to minimize exposure to untrusted networks. Regularly audit and review Splunk configurations and logs to identify unusual indexing failures or service disruptions. Develop and test incident response plans specifically addressing potential Splunk service outages to ensure rapid recovery. Engage with Splunk support and subscribe to security advisories to stay informed about patches and emerging threats.