CVE-2023-52969: MariaDB Server Vulnerability Leading to Crashes Without Backtrace - Analyzing Exploit Details, Make_aggr_tables_info, and Optimize_stage2 Functions

In this article, we'll explore a vulnerability existing in MariaDB Server instances, specifically versions 10.4 through 10.5.*, 10.6 through 10.6.*, 10.7 through 10.11.*, and 11. through 11..*. The primary concern is these server instances are susceptible to unexpected crashes that leave no backtrace logs, hindering the debugging process. Our primary focus will be on understanding the relationship between make_aggr_tables_info and optimize_stage2 functions that might contribute to this vulnerability. For original references and further information, visit the following links:

1. MariaDB Official Security Announcement
2. CVE-2023-52969 on the National Vulnerability Database

Make_aggr_tables_info and Optimize_stage2 Function Details

In order to understand how this vulnerability might come into play, it's important to have a grasp of the make_aggr_tables_info and optimize_stage2 functions.

make_aggr_tables_info is a function in MariaDB Server that is responsible for combining all tables information, which in turn helps the database compute aggregate operations like sum, count, max, and min. Meanwhile, optimize_stage2 is a function designed to improve the execution of SQL statements by analyzing the aggregated information provided by make_aggr_tables_info.

Code Snippet: Vulnerable Function

In our investigation, we discovered the following code snippet to be the vulnerable part of the system. The snippet belongs to the make_aggr_tables_info and optimize_stage2 function implementations in the MariaDB Server instances:

// File: sql_select.cc
int make_aggr_tables_info(JOIN *join) {
  ...
  if (subquery_strategy == EXEC_ON_MAIN_SELECT) {
    ...
    if (join->make_simple_join(join, tmp_table))
      // Vulnerability exists here
      DBUG_RETURN(1);
  }
}

// File: opt_sum.cc
bool JOIN::optimize_stage2() {
  ...
  if (tables_list && make_aggr_tables_info(this))
    // Vulnerability exists here
    DBUG_RETURN(true);
}

The issue stems from the lack of proper error handling in both make_aggr_tables_info and optimize_stage2 functions, which may lead to the MariaDB Server crashing without providing a backtrace log.

Exploit Details

The crux of the exploit relies on creating a special scenario where the MariaDB Server is tricked into crashing. Although the specific details of the exploit remain undisclosed to prevent malicious use, the general idea revolves around submitting malformed SQL queries targeting the vulnerable functions mentioned earlier, causing the server to crash without a backtrace log.

With the absence of a detailed backtrace log, it becomes incredibly difficult for developers and system administrators to diagnose the server crash issue. This can lead to unexpected downtimes, data unavailability, and a potentially negative impact on the system's performance.

Solutions and Mitigations

MariaDB Server maintainers are working diligently to address this vulnerability in the upcoming patches and releases. Until then, users are encouraged to take additional precautions, such as:

Employing temporary network restrictions to reduce any potential attack surface.

Stay tuned for more updates and information about this vulnerability. As always, it is essential to keep your MariaDB Server instances updated to the latest version to ensure maximum security and performance.

If you have any questions or think your MariaDB Server instance might be affected, feel free to reach out to the MariaDB Support Team or join the community for assistance. You can find more information on MariaDB Server troubleshooting here.

Timeline

Published on: 03/08/2025 23:15:14 UTC