CVE-2019-4236 in Spectrum Protect
Summary
by MITRE
A IBM Spectrum Protect 7.l client backup or archive operation running for an HP-UX VxFS object is silently skipping Access Control List (ACL) entries from backup or archive if there are more than twelve ACL entries associated with the object in total. As a result, it could allow a local attacker to restore or retrieve the object with incorrect ACL entries. IBM X-Force ID: 159418.
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Analysis
by VulDB Data Team • 11/05/2023
The vulnerability identified as CVE-2019-4236 affects IBM Spectrum Protect 7.1 client software when processing backup or archive operations involving HP-UX VxFS objects. This issue represents a critical data integrity and access control flaw that manifests during the backup process of file systems that utilize VxFS as their underlying storage mechanism. The vulnerability specifically impacts systems where HP-UX operating systems are configured with VxFS file systems, creating a scenario where access control information becomes corrupted during the backup operation. The flaw operates silently without alerting administrators or users to the data loss, making it particularly dangerous as it can go undetected for extended periods. This vulnerability directly impacts the principle of least privilege and access control enforcement within enterprise backup environments where proper ACL handling is essential for maintaining data security and compliance requirements.
The technical root cause of this vulnerability stems from an implementation limitation within the IBM Spectrum Protect client software that fails to properly handle access control lists exceeding twelve entries during backup operations. When VxFS objects contain more than twelve ACL entries, the system silently truncates or omits these additional entries from the backup process, resulting in incomplete access control information being stored. This behavior violates fundamental data integrity principles and represents a classic case of incomplete input validation and data handling. The vulnerability operates at the file system level during backup operations, specifically affecting how the client software processes and stores ACL information for VxFS objects. This flaw falls under the category of incomplete data processing and can be classified as a CWE-20: Improper Input Validation, where the system fails to properly validate and handle the complete set of access control information. The silent nature of this failure means that the backup process appears successful while simultaneously corrupting critical access control metadata.
The operational impact of this vulnerability extends far beyond simple data loss, creating significant security risks for organizations relying on IBM Spectrum Protect for their backup and recovery operations. Local attackers who gain access to systems running affected versions can exploit this vulnerability to restore files with incorrect ACL entries, potentially allowing unauthorized users to access sensitive data that should be restricted. This creates a privilege escalation scenario where users who should not have access to certain files or directories can gain access through the corrupted backup restore process. The vulnerability undermines the integrity of the backup system itself, as the restored data may not accurately reflect the original access control permissions. Organizations using this backup solution may face compliance violations and security incidents when backup restores fail to maintain proper access controls, particularly in regulated environments where audit trails and access control enforcement are mandatory. The impact is particularly severe for systems handling sensitive data where proper access control is essential for maintaining data confidentiality and integrity.
Mitigation strategies for CVE-2019-4236 should prioritize immediate patching of affected IBM Spectrum Protect client installations with the vendor-provided security updates. Organizations should implement monitoring procedures to detect and alert on backup operations that may have been affected by this vulnerability, particularly focusing on backup jobs involving HP-UX VxFS objects. System administrators should conduct thorough audits of backup and restore operations to identify any instances where ACL information may have been lost during backup processing. The recommended approach includes implementing additional verification procedures where backup operations are validated to ensure all ACL entries are properly preserved and restored. Organizations should also consider implementing network segmentation and access controls to limit local system access, reducing the attack surface for potential exploitation. From an ATT&CK perspective, this vulnerability relates to T1078 Valid Accounts and T1565 Data Manipulation, as it allows for both unauthorized access through corrupted ACLs and data integrity manipulation. Additionally, organizations should review their backup and recovery procedures to ensure that access control information is properly validated during restore operations, implementing checksums or other verification mechanisms to detect corrupted ACL data. The vulnerability demonstrates the importance of comprehensive testing of backup solutions with various file system configurations and access control scenarios to prevent silent data corruption during critical system operations.