CVE-2016-10100 in Borg
Summary
by MITRE
Borg (aka BorgBackup) before 1.0.9 has a flaw in the way duplicate archive names were processed during manifest recovery, potentially allowing an attacker to overwrite an archive.
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Analysis
by VulDB Data Team • 01/03/2017
The vulnerability identified as CVE-2016-10100 affects BorgBackup, a deduplicating backup tool that has gained significant adoption in enterprise environments for its efficient storage utilization and security features. This flaw exists in versions prior to 1.0.9 and specifically impacts the manifest recovery process within the backup system. The issue stems from how Borg handles duplicate archive names during the recovery phase, creating a potential security risk that could be exploited by malicious actors. The vulnerability represents a critical weakness in the backup system's integrity mechanisms, particularly when dealing with archive management and recovery operations.
The technical flaw manifests in the manifest recovery algorithm where Borg fails to properly validate or reject duplicate archive names during the recovery process. When an attacker can manipulate or control the backup manifest data, they can potentially create a scenario where duplicate archive names exist in the system. The system's insufficient validation logic allows these duplicates to be processed without proper safeguards, leading to a condition where an attacker could overwrite existing archives with malicious content. This represents a failure in input validation and archive name handling that violates fundamental security principles of data integrity and access control. The vulnerability aligns with CWE-126, which describes "Buffer Over-read" conditions that can occur when systems fail to properly validate input data, and also relates to CWE-20, which covers "Improper Input Validation" in software systems.
The operational impact of this vulnerability extends beyond simple data overwrite scenarios, potentially enabling attackers to compromise backup integrity and availability. In enterprise environments where BorgBackup serves as a critical component of disaster recovery and data protection strategies, this flaw could allow unauthorized users to manipulate backup archives, potentially leading to data loss or the introduction of malicious content into backup repositories. The attack vector typically involves scenarios where an attacker has access to modify or influence the backup manifest files, either through direct system access, network interception, or other privilege escalation techniques. This vulnerability particularly affects organizations that rely heavily on automated backup processes and may not have robust monitoring or integrity verification mechanisms in place.
Organizations should immediately upgrade to BorgBackup version 1.0.9 or later to remediate this vulnerability, as no effective workarounds exist for the core flaw in the manifest recovery process. System administrators should implement comprehensive monitoring of backup manifest files and archive operations to detect potential exploitation attempts. The mitigation strategy should include regular integrity checks of backup repositories, implementation of access controls for backup manifest files, and consideration of additional validation layers in backup processes. Security teams should also review their incident response procedures to ensure they can detect and respond to potential archive overwrites. This vulnerability demonstrates the importance of maintaining current security patches in backup systems, as backup tools often contain critical security features that, when compromised, can lead to widespread data integrity issues. The flaw emphasizes the need for robust validation mechanisms in all aspects of backup and recovery systems, particularly those handling critical organizational data. Organizations should also consider implementing additional security controls such as digital signatures for backup manifests and regular integrity verification procedures to prevent exploitation of similar vulnerabilities in the future.