CVE-2022-24048: MariaDB Privilege Escalation Vulnerability

CVE-2022-24048 Overview

CVE-2022-24048 is a stack-based buffer overflow vulnerability in the MariaDB CONNECT Storage Engine that enables local attackers to escalate privileges on affected installations. The flaw exists within the processing of SQL queries, where insufficient validation of user-supplied data length allows attackers to overflow a fixed-length stack-based buffer. Successful exploitation grants attackers the ability to execute arbitrary code in the context of the MariaDB service account, potentially leading to complete system compromise.

Critical Impact

Local attackers with low privileges can leverage this stack-based buffer overflow to escalate privileges and execute arbitrary code as the MariaDB service account, potentially compromising database integrity and system security.

Affected Products

• MariaDB versions prior to patched releases (multiple version branches affected)
• Fedora 34, 35, and 36 (packages prior to security updates)
• MariaDB 10.8.0

Discovery Timeline

• 2022-02-18 - CVE-2022-24048 published to NVD
• 2024-11-21 - Last updated in NVD database

Technical Details for CVE-2022-24048

Vulnerability Analysis

This vulnerability is classified as CWE-121 (Stack-based Buffer Overflow) and was originally tracked by the Zero Day Initiative as ZDI-CAN-16191. The CONNECT storage engine in MariaDB provides functionality for accessing external data sources, but contains a critical flaw in how it processes SQL queries.

When handling user-supplied data during query processing, the affected code fails to properly validate input length before copying data into a fixed-length stack-based buffer. This oversight allows an authenticated attacker to supply crafted input that exceeds the buffer's capacity, overwriting adjacent stack memory including return addresses and saved registers.

The local attack vector requires the attacker to have existing authentication to the MariaDB instance. However, once authenticated—even with minimal database privileges—the attacker can execute specially crafted SQL queries targeting the CONNECT storage engine to trigger the buffer overflow condition.

Root Cause

The root cause lies in the CONNECT storage engine's failure to implement proper bounds checking on user-supplied data. Specifically, when processing certain SQL query parameters, the code copies user-controlled input directly to a stack-allocated buffer without verifying that the input length does not exceed the buffer's allocated size. This classic programming error enables attackers to corrupt stack memory with controlled data.

Attack Vector

The attack requires local access and authentication to the MariaDB database server. An attacker with valid credentials—regardless of their privilege level within the database—can construct malicious SQL queries that exploit the CONNECT storage engine. The crafted queries contain oversized input data designed to overflow the vulnerable stack buffer. When the overflow occurs, the attacker can overwrite critical stack structures, hijack program execution flow, and ultimately execute arbitrary code with the privileges of the MariaDB service account.

The vulnerability exploitation follows a typical stack-based buffer overflow attack pattern:

1. Attacker authenticates to the MariaDB instance
2. Attacker crafts a SQL query targeting the CONNECT storage engine with oversized input
3. The vulnerable code copies the oversized input to a fixed-length stack buffer
4. Stack corruption occurs, overwriting return addresses
5. Attacker gains code execution in the context of the MariaDB service

Detection Methods for CVE-2022-24048

Indicators of Compromise

• Unusual or malformed SQL queries targeting the CONNECT storage engine with abnormally long parameter values
• MariaDB service crashes or unexpected restarts following query execution
• Evidence of privilege escalation from database service accounts
• Suspicious process spawning from the MariaDB process context

Detection Strategies

• Monitor MariaDB error logs for segmentation faults or stack corruption indicators during CONNECT engine operations
• Implement database activity monitoring to detect unusual query patterns with excessive input lengths
• Deploy endpoint detection and response (EDR) solutions to identify anomalous behavior from database service processes
• Review authentication logs for unusual access patterns preceding service anomalies

Monitoring Recommendations

• Enable verbose logging for the CONNECT storage engine to capture detailed query information
• Configure alerts for MariaDB service crashes or unexpected terminations
• Monitor for process execution anomalies originating from database service accounts
• Implement network segmentation to limit the blast radius of potential privilege escalation

How to Mitigate CVE-2022-24048

Immediate Actions Required

• Upgrade MariaDB to the latest patched version for your version branch immediately
• If unable to patch, consider disabling the CONNECT storage engine if not required for operations
• Review and restrict database user privileges to minimize authenticated attack surface
• Implement network-level access controls to limit database connectivity to trusted hosts only

Patch Information

MariaDB has released security updates addressing this vulnerability across multiple version branches. Administrators should consult the MariaDB Security Overview for specific version information and download patched releases.

For Fedora users, security updates are available through the standard package management system. Relevant advisories have been published on the Fedora Package Announcement mailing list.

Additional vendor information is available from the NetApp Security Advisory and the ZDI-22-363 Advisory.

Workarounds

• Disable the CONNECT storage engine if it is not essential for database operations by removing or unloading the plugin
• Implement strict input validation at the application layer before data reaches the database
• Restrict database access to trusted users and applications only
• Run MariaDB with minimal system privileges to limit the impact of successful exploitation

# Disable CONNECT storage engine if not required
# Add to my.cnf configuration file
[mysqld]
plugin-load-add = ha_connect.so
# Comment out or remove the above line to disable CONNECT engine

# Alternatively, uninstall the plugin at runtime (if loaded)
# mysql -u root -p -e "UNINSTALL PLUGIN CONNECT;"