CVE-2023-22942 in Splunk
Summary
by MITRE • 02/14/2023
In Splunk Enterprise versions below 8.1.13, 8.2.10, and 9.0.4, a cross-site request forgery in the Splunk Secure Gateway (SSG) app in the ‘kvstore_client’ REST endpoint lets a potential attacker update SSG [App Key Value Store (KV store)](https://docs.splunk.com/Documentation/Splunk/latest/Admin/AboutKVstore) collections using an HTTP GET request. SSG is a Splunk-built app that comes with Splunk Enterprise. The vulnerability affects instances with SSG and Splunk Web enabled.
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Analysis
by VulDB Data Team • 03/16/2023
The vulnerability identified as CVE-2023-22942 represents a critical cross-site request forgery weakness within Splunk Enterprise's Secure Gateway application, specifically impacting versions prior to 8.1.13, 8.2.10, and 9.0.4. This flaw exists within the kvstore_client REST endpoint of the Splunk Secure Gateway app, which is a built-in component designed to provide secure communication between Splunk instances and external systems. The vulnerability arises from the application's improper validation of HTTP request methods, allowing malicious actors to exploit the GET request handler to perform unauthorized modifications to the Key-Value Store collections that are fundamental to the Secure Gateway's operation. The Secure Gateway app serves as a bridge for secure data transmission and configuration management, making this vulnerability particularly dangerous as it could compromise the integrity of the entire secure communication infrastructure.
The technical exploitation of this vulnerability stems from the insecure implementation of the REST endpoint's access controls, where the system accepts GET requests for operations that should typically require POST or PUT methods to modify data. This design flaw enables attackers to craft malicious URLs that, when visited by authenticated users, automatically execute unauthorized modifications to the KV store collections used by the Secure Gateway. The attack vector is particularly insidious because it leverages the trust relationship between the Splunk web interface and its users, requiring no additional authentication or privilege escalation. The vulnerability is classified under CWE-352, which specifically addresses Cross-Site Request Forgery, and aligns with ATT&CK technique T1566.001 for initial access through spearphishing attachments, as attackers could potentially embed malicious links within phishing emails that would execute the CSRF attack when users navigate to them within their Splunk session.
The operational impact of this vulnerability extends beyond simple data modification, as it could lead to complete compromise of the Secure Gateway's configuration management system. Attackers could potentially modify authentication tokens, connection parameters, or other critical configuration data stored in the KV store, resulting in unauthorized access to connected systems or complete disruption of secure communication channels. The implications are particularly severe in enterprise environments where Splunk serves as a central monitoring and security platform, as the compromise of the Secure Gateway could enable attackers to escalate their privileges and gain access to sensitive operational data. The vulnerability affects all Splunk Enterprise installations that have both SSG enabled and Splunk Web accessible, making it particularly widespread across organizations that utilize Splunk's secure communication capabilities. Organizations may face significant compliance and security implications, as this vulnerability could be exploited to bypass security controls and potentially exfiltrate sensitive data through compromised secure gateway connections. The recommended mitigation strategy involves immediate patching to versions 8.1.13, 8.2.10, or 9.0.4, along with implementing additional network segmentation controls and monitoring for unusual patterns in REST API access, particularly GET requests to endpoints that should not accept modification operations.