CVE-2020-10997 in XtraBackup
Summary
by MITRE
Percona XtraBackup before 2.4.20 unintentionally writes the command line to any resulting backup file output. This may include sensitive arguments passed at run time. In addition, when --history is passed at run time, this command line is also written to the PERCONA_SCHEMA.xtrabackup_history table.
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Analysis
by VulDB Data Team • 10/12/2020
This vulnerability in Percona XtraBackup affects versions prior to 2.4.20 and represents a significant information disclosure risk through improper handling of command line arguments during backup operations. The flaw occurs when the backup process unintentionally persists command line parameters to output files and database tables, potentially exposing sensitive information that was passed as runtime arguments. This behavior creates a persistent exposure risk where confidential data including passwords, encryption keys, or other sensitive parameters may be inadvertently stored in backup artifacts that are typically archived for long-term storage.
The technical implementation of this vulnerability stems from insufficient sanitization of command line arguments before they are written to backup metadata files and database tables. When users execute backup operations with sensitive parameters, these values are not properly filtered or redacted before being stored in the resulting backup files. Additionally, the --history parameter exacerbates the issue by writing the complete command line to the PERCONA_SCHEMA.xtrabackup_history table, creating a database-level exposure that persists across backup operations and potentially across system reboots. This design flaw violates fundamental security principles of least privilege and data minimization, as it indiscriminately stores all command line arguments without considering their sensitivity or potential impact if compromised.
The operational impact of this vulnerability extends beyond simple information disclosure to encompass potential privilege escalation and credential compromise scenarios. Attackers who gain access to backup files or database tables containing the stored command line arguments could extract sensitive runtime parameters that were passed to the backup process. This exposure could lead to authentication credential theft, encryption key compromise, or access to other sensitive system components that were passed as command line arguments during backup execution. The vulnerability is particularly concerning in environments where backup files are stored on systems with limited access controls or where database administrators have elevated privileges that could be leveraged to extract the stored information. This flaw aligns with CWE-200 (Information Exposure) and CWE-312 (Sensitive Data Exposure) categories, and could be exploited through techniques described in ATT&CK matrix under T1005 (Data from Local System) and T1070 (Indicator Removal on Host).
Organizations should immediately upgrade to Percona XtraBackup version 2.4.20 or later to remediate this vulnerability, as no effective workarounds exist that can be implemented without modifying the core backup process. The recommended mitigation strategy involves implementing proper input sanitization and argument filtering mechanisms that prevent sensitive parameters from being stored in backup metadata. System administrators should also conduct comprehensive audits of existing backup files and database tables to identify and remove any previously exposed sensitive information. Additional protective measures include implementing strict access controls on backup storage systems, monitoring database table access for the PERCONA_SCHEMA.xtrabackup_history table, and establishing regular security scanning procedures to detect potential exposure of command line arguments in backup artifacts. The vulnerability demonstrates the critical importance of secure coding practices in backup and recovery systems where sensitive data handling is paramount to overall system security posture.