CVE-2022-32155 in Splunk
Summary
by MITRE • 06/15/2022
In universal forwarder versions before 9.0, management services are available remotely by default. When not required, it introduces a potential exposure, but it is not a vulnerability. If exposed, we recommend each customer assess the potential severity specific to your environment. In 9.0, the universal forwarder now binds the management port to localhost preventing remote logins by default. If management services are not required in versions before 9.0, set disableDefaultPort = true in server.conf OR allowRemoteLogin = never in server.conf OR mgmtHostPort = localhost in web.conf. See Configure universal forwarder management security (https://docs.splunk.com/Documentation/Splunk/9.0.0/Security/EnableTLSCertHostnameValidation#Configure_universal_forwarder_management_security) for more information on disabling the remote management services.
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Analysis
by VulDB Data Team • 06/15/2022
The vulnerability described in CVE-2022-32155 relates to the default configuration of Splunk universal forwarder management services in versions prior to 9.0. This issue represents a significant security concern as it exposes management interfaces to remote network access without explicit configuration by administrators. The default behavior creates an attack surface that could be exploited by malicious actors to gain unauthorized access to forwarder management functions, potentially leading to system compromise or data exfiltration. This configuration flaw directly violates the principle of least privilege and default security hardening practices that are fundamental to secure system administration.
The technical flaw stems from the universal forwarder's default binding of management services to network interfaces rather than restricting them to localhost. This misconfiguration allows any remote attacker with network access to connect to the management port and potentially execute commands or manipulate forwarder settings. The vulnerability manifests as a network service exposure where management interfaces remain accessible over the network, creating an entry point for various attack vectors including credential brute force, privilege escalation, and remote code execution if authentication is bypassed. This issue is categorized under CWE-276 as improper privilege management and aligns with ATT&CK technique T1078 for valid accounts and T1105 for command and script interpreter.
The operational impact of this vulnerability extends beyond simple exposure as it affects the security posture of organizations relying on Splunk universal forwarders for data collection and monitoring. Organizations may unknowingly maintain systems with open management ports, creating persistent security risks that could be exploited during network reconnaissance phases. The vulnerability becomes particularly dangerous in environments where forwarders are deployed in untrusted network segments or where network segmentation is not properly implemented. Remote attackers can leverage this exposure to gain administrative access to forwarders, potentially compromising the entire data collection pipeline and enabling persistent surveillance or data manipulation.
Effective mitigation strategies for this vulnerability require immediate configuration changes to restrict management service accessibility. Organizations using universal forwarder versions before 9.0 should implement one of three recommended approaches: setting disableDefaultPort = true in server.conf to completely disable the default management port, configuring allowRemoteLogin = never in server.conf to prevent remote login attempts, or binding mgmtHostPort = localhost in web.conf to restrict access to local host only. These configuration changes align with industry best practices for service hardening and directly address the root cause of the vulnerability. The release of Splunk 9.0 introduced automatic localhost binding for management ports, demonstrating the vendor's recognition of this security weakness and providing a built-in solution for organizations upgrading their deployments.