CVE-2022-24051: MariaDB Privilege Escalation Vulnerability

CVE-2022-24051 Overview

CVE-2022-24051 is a format string vulnerability affecting the MariaDB CONNECT Storage Engine that allows local attackers to escalate privileges on affected installations. The vulnerability exists within the processing of SQL queries, where a user-supplied string is improperly used as a format specifier without proper validation. Successfully exploiting this flaw enables attackers to escalate privileges and execute arbitrary code in the context of the MariaDB service account.

This vulnerability was tracked by the Zero Day Initiative as ZDI-CAN-16193 and requires authentication to exploit. While the attack vector is local, the potential impact is significant as it can lead to complete compromise of the affected database server.

Critical Impact

Authenticated local attackers can leverage this format string vulnerability to escalate privileges and execute arbitrary code with the permissions of the MariaDB service account, potentially leading to full system compromise.

Affected Products

• MariaDB (multiple versions including 10.8.0)
• Fedora 34
• Fedora 35
• Fedora 36

Discovery Timeline

• 2022-02-18 - CVE-2022-24051 published to NVD
• 2024-11-21 - Last updated in NVD database

Technical Details for CVE-2022-24051

Vulnerability Analysis

This vulnerability is classified as CWE-134 (Use of Externally-Controlled Format String). Format string vulnerabilities occur when user-controllable input is passed directly to a format function (such as printf() family functions in C/C++) as the format specifier argument rather than as a data argument.

In the context of the MariaDB CONNECT Storage Engine, the flaw manifests during SQL query processing. When a maliciously crafted query containing format specifiers (such as %s, %n, %x) is submitted, the database engine incorrectly interprets these as formatting instructions rather than literal string data.

The CONNECT Storage Engine is designed to enable MariaDB to access external data sources and file formats. This functionality requires parsing and processing various user-provided strings, creating an attack surface for format string exploitation.

Root Cause

The root cause is the lack of proper validation and sanitization of user-supplied strings before using them as format specifiers in format functions. The vulnerable code path within the CONNECT Storage Engine passes user-controlled data directly to a format function, allowing attackers to:

• Read from arbitrary memory locations using format specifiers like %x or %s
• Write to arbitrary memory locations using the %n specifier
• Cause denial of service through malformed format strings
• Achieve code execution by overwriting function pointers or return addresses

Attack Vector

The attack requires local access to the MariaDB server and valid authentication credentials. An attacker with database access can craft malicious SQL queries targeting the CONNECT Storage Engine that include format string specifiers. The exploitation flow involves:

1. Authenticating to the MariaDB instance with valid credentials
2. Crafting SQL queries that utilize the CONNECT Storage Engine functionality
3. Injecting format string specifiers into query parameters that are processed without proper sanitization
4. Leveraging memory read/write primitives to achieve privilege escalation
5. Executing arbitrary code within the context of the MariaDB service account

The vulnerability mechanism involves user-supplied strings being passed to format functions. When format specifiers like %x (hexadecimal output), %s (string pointer dereference), or %n (write number of bytes) are included in the input, the format function interprets these as instructions rather than data. The %n specifier is particularly dangerous as it writes to memory, enabling attackers to modify program state and achieve code execution.

For detailed technical information, refer to the Zero Day Initiative Advisory ZDI-22-318.

Detection Methods for CVE-2022-24051

Indicators of Compromise

• Unusual SQL queries targeting the CONNECT Storage Engine containing format specifiers (%s, %x, %n, %p)
• MariaDB service crashes or unexpected restarts that may indicate exploitation attempts
• Anomalous privilege escalation events associated with the MariaDB service account
• Unexpected memory access patterns or segmentation faults in MariaDB logs

Detection Strategies

• Monitor MariaDB query logs for suspicious patterns containing format string specifiers in CONNECT Storage Engine operations
• Implement database activity monitoring to detect unusual query structures or authentication patterns
• Deploy endpoint detection solutions capable of identifying format string exploitation attempts
• Review MariaDB error logs for signs of memory corruption or service instability

Monitoring Recommendations

• Enable detailed query logging for the MariaDB server to capture all SQL statements
• Configure alerting for abnormal database service behavior including unexpected restarts
• Monitor system-level events for privilege escalation attempts originating from the MariaDB process
• Implement file integrity monitoring on MariaDB binaries and configuration files

How to Mitigate CVE-2022-24051

Immediate Actions Required

• Update MariaDB to the latest patched version that addresses CVE-2022-24051
• Review and restrict user permissions to minimize the number of accounts with CONNECT Storage Engine access
• Audit authentication logs to identify any potentially compromised accounts
• Consider temporarily disabling the CONNECT Storage Engine if not required for operations

Patch Information

MariaDB has released security updates to address this vulnerability. Administrators should consult the MariaDB Security Overview for the latest patch information and upgrade instructions. Fedora users should apply the security updates available through the standard package management system, as referenced in the Fedora Package Announcements.

Additional vendor information is available from NetApp Security Advisory NTAP-20220318-0004.

Workarounds

• If the CONNECT Storage Engine is not required, disable it by removing the ha_connect.so plugin
• Restrict database user privileges following the principle of least privilege
• Implement network-level controls to limit local access to the MariaDB server
• Deploy application-level input validation to filter format string specifiers before they reach the database

# Disable CONNECT Storage Engine (if not required)
# Add to MariaDB configuration file (my.cnf or mariadb.conf.d/)
[mysqld]
plugin-load-add=ha_connect=OFF

# Alternatively, uninstall the plugin via SQL
# UNINSTALL SONAME 'ha_connect';