CVE-2017-7549 in OpenStack
Summary
by MITRE
A flaw was found in instack-undercloud 7.2.0 as packaged in Red Hat OpenStack Platform Pike, 6.1.0 as packaged in Red Hat OpenStack Platform Oacta, 5.3.0 as packaged in Red Hat OpenStack Newton, where pre-install and security policy scripts used insecure temporary files. A local user could exploit this flaw to conduct a symbolic-link attack, allowing them to overwrite the contents of arbitrary files.
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Analysis
by VulDB Data Team • 11/05/2024
The vulnerability identified as CVE-2017-7549 represents a critical security flaw within the instack-undercloud deployment tooling used in Red Hat OpenStack Platform environments. This issue affects multiple versions of the OpenStack platform including Pike, Ocata, and Newton releases, making it a widespread concern across several major OpenStack iterations. The flaw resides in how the pre-install and security policy scripts handle temporary file creation during the deployment process, creating exploitable conditions that could be leveraged by malicious actors.
The technical implementation of this vulnerability stems from the insecure handling of temporary files within the deployment scripts. When these scripts execute, they create temporary files without proper security measures to prevent symbolic link attacks. The underlying issue manifests when the scripts use predictable temporary file names or fail to validate the ownership and permissions of temporary file locations. This insecure pattern allows a local attacker with access to the system to create malicious symbolic links in the temporary file directories, effectively manipulating the script's behavior to write content to arbitrary locations on the filesystem.
The operational impact of this vulnerability extends beyond simple privilege escalation as it provides attackers with the capability to overwrite critical system files, configuration files, or even binaries that the deployment scripts might access. This creates a potential for persistent compromise of the OpenStack deployment environment, allowing attackers to modify system configurations, inject malicious code, or disrupt the normal operation of the cloud infrastructure. The vulnerability particularly affects environments where the deployment scripts are executed with elevated privileges, amplifying the potential damage that can be achieved.
From a cybersecurity perspective, this vulnerability aligns with CWE-377, which addresses insecure temporary file handling, and maps to ATT&CK technique T1059.001 for execution through command-line interfaces. The attack vector specifically follows the pattern of symbolic link manipulation, where attackers exploit predictable temporary file creation patterns to gain unauthorized file system access. The vulnerability demonstrates the importance of proper temporary file management in automated deployment tools and highlights the risks associated with insufficient input validation in system administration scripts.
Mitigation strategies for this vulnerability require immediate patching of affected OpenStack installations through the official Red Hat security updates. System administrators should also implement additional protective measures including restricting write permissions on temporary directories, implementing proper file ownership validation, and conducting regular security audits of deployment scripts. The remediation process should include verifying that temporary files are created with secure permissions and that symbolic link attacks are properly detected and prevented through proper validation mechanisms. Organizations should also consider implementing automated monitoring solutions to detect anomalous file system activities that might indicate exploitation attempts against similar vulnerabilities.