CVE-2018-1088 in Gluster
Summary
by MITRE
A privilege escalation flaw was found in gluster 3.x snapshot scheduler. Any gluster client allowed to mount gluster volumes could also mount shared gluster storage volume and escalate privileges by scheduling malicious cronjob via symlink.
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Analysis
by VulDB Data Team • 02/28/2023
The vulnerability identified as CVE-2018-1088 represents a critical privilege escalation flaw within the gluster 3.x snapshot scheduler component, fundamentally compromising the security model of distributed storage systems. This issue affects organizations relying on gluster filesystem for their data storage infrastructure, particularly those utilizing snapshot scheduling features for backup and recovery operations. The vulnerability stems from insufficient access controls and improper privilege management within the snapshot scheduler implementation, creating a pathway for unauthorized users to gain elevated system privileges through carefully crafted malicious operations.
The technical flaw manifests through a symlink manipulation attack vector that exploits the snapshot scheduler's handling of file system references. When gluster clients mount volumes, they inadvertently expose the underlying storage structure to potential attackers who can create symbolic links pointing to sensitive system resources. The vulnerability specifically targets the cron job scheduling mechanism within the snapshot functionality, allowing attackers to inject malicious code through symlinked references that the scheduler will execute with elevated privileges. This represents a classic case of insufficient input validation and improper privilege separation, aligning with CWE-264 permissions, privileges, and access controls weakness classification.
The operational impact of this vulnerability extends beyond simple privilege escalation to potentially enable full system compromise and data exfiltration. An attacker with minimal access to mount gluster volumes can leverage this vulnerability to execute arbitrary code with root privileges, effectively bypassing the entire security boundary designed to protect the storage infrastructure. The attack chain typically involves mounting a shared gluster volume, creating malicious symlinks that point to system-critical files or directories, and then scheduling snapshot operations that trigger the execution of the malicious payload through the compromised scheduler. This vulnerability directly impacts the CIA triad by compromising confidentiality, integrity, and availability of the affected systems.
Organizations should implement immediate mitigations including disabling snapshot scheduling features until patches are applied, implementing strict access controls on gluster volume mounts, and monitoring for suspicious symlink creation activities. The recommended approach involves applying vendor-provided security patches, restricting user permissions for gluster client operations, and implementing network segmentation to limit access to storage resources. Additionally, system administrators should conduct comprehensive audits of existing symlink configurations and implement automated monitoring solutions to detect anomalous scheduling activities. This vulnerability demonstrates the critical importance of proper privilege separation in distributed storage systems and aligns with ATT&CK technique T1068 for local privilege escalation through scheduled tasks and T1078 for valid accounts usage to maintain access. Organizations must also consider implementing principle of least privilege policies and regular security assessments of their storage infrastructure to prevent similar vulnerabilities from being exploited in production environments.