CVE-2017-15111 in keycloak-httpd-client-install
Summary
by MITRE
keycloak-httpd-client-install versions before 0.8 insecurely creates temporary file allowing local attackers to overwrite other files via symbolic link.
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Analysis
by VulDB Data Team • 02/02/2023
The vulnerability identified as CVE-2017-15111 affects keycloak-httpd-client-install versions prior to 08, presenting a critical security flaw in the temporary file creation process. This issue arises from improper handling of temporary file operations within the client installation utility that manages Keycloak authentication integration with httpd servers. The flaw enables local attackers to exploit a race condition in temporary file creation, allowing them to manipulate the system's file permissions and overwrite arbitrary files through symbolic link manipulation. The vulnerability specifically targets the installation script's methodology for creating temporary files during the Keycloak client configuration process, where insufficient validation of temporary file paths and inadequate permission controls are implemented.
The technical implementation of this vulnerability stems from the insecure creation of temporary files without proper atomic operations or secure directory handling mechanisms. When the keycloak-httpd-client-install utility executes, it generates temporary files in predictable locations without employing secure temporary file creation functions that would prevent symbolic link attacks. This insecure practice aligns with CWE-377, which addresses insecure temporary file creation vulnerabilities, and CWE-378, which covers the creation of temporary files with insecure permissions. The flaw operates under the principle of time-of-check to time-of-use race conditions where an attacker can create a symbolic link in the temporary file path between the time the utility checks for the file's existence and when it actually writes to the file. Attackers can leverage this to overwrite files with malicious content, potentially compromising system integrity and allowing privilege escalation.
The operational impact of this vulnerability extends beyond simple file overwriting, as it creates a pathway for attackers to manipulate critical system components and potentially gain elevated privileges. Local attackers with minimal system access can exploit this weakness to overwrite configuration files, binary executables, or system libraries, leading to privilege escalation or persistent backdoor installation. The attack vector is particularly concerning in environments where the keycloak-httpd-client-install utility is executed with elevated privileges during system administration tasks. This vulnerability can be exploited to compromise the authentication infrastructure that Keycloak provides, undermining the security posture of organizations relying on this authentication framework. The attack requires only local access and basic knowledge of symbolic link manipulation techniques, making it accessible to attackers with limited sophistication while maintaining significant impact potential.
Mitigation strategies for CVE-2017-15111 should prioritize immediate patching of affected keycloak-httpd-client-install versions to 08 or later, which implements secure temporary file creation mechanisms. Organizations should also implement strict file permission controls and audit temporary file usage patterns within their systems. The recommended approach includes using secure temporary file creation functions that provide atomic operations and proper directory permissions, such as mkstemp or similar secure APIs that prevent symbolic link attacks. System administrators should conduct comprehensive vulnerability assessments to identify any installations that may have been compromised through this vulnerability and implement monitoring for unauthorized file modifications. Additionally, implementing the principle of least privilege for the keycloak-httpd-client-install utility execution and employing automated security scanning tools can help detect similar insecure temporary file creation patterns in other software components. The remediation process should also include regular security updates and patch management procedures to prevent similar vulnerabilities from emerging in other system components.