CVE-2024-57626

Executive Summary

CVE-2024-57626 is a denial-of-service (DoS) vulnerability in the MonetDB Server v11.49.1, specifically within the mat_join2 component. An attacker can exploit this flaw by sending crafted SQL statements, causing the database server to crash or become unresponsive. The vulnerability has a CVSS score of 0.0 (likely unassigned or placeholder), but the impact is a complete service disruption. No public proof-of-concept (PoC) or patch is currently available. The EPSS score is 0.0%, indicating low exploitation likelihood in the wild, but the risk remains for targeted attacks.

Supply Chain & Package Security

MonetDB is an open-source column-oriented database management system. This vulnerability affects the core server binary, not a package manager distribution (NPM, PyPI, Go, Ruby). Therefore, supply chain risks are limited to direct deployment of the vulnerable server version.

CVSS Breakdown & Threat Level

• CVSS Score: 0.0 (Unassigned)
• Attack Vector (AV): Network (likely)
• Attack Complexity (AC): Low (likely)
• Privileges Required (PR): None (likely)
• User Interaction (UI): None (likely)
• Scope (S): Unchanged
• Confidentiality (C): None
• Integrity (I): None
• Availability (A): High
• Threat Level: Medium (due to DoS impact and lack of patch)

Deep Dive & Mechanics

The vulnerability resides in the mat_join2 component of MonetDB Server v11.49.1. This component handles materialized join operations, which are used to optimize query performance by pre-computing join results. The flaw is triggered by specially crafted SQL statements that cause an infinite loop, memory exhaustion, or a null pointer dereference within the mat_join2 logic.

Root Cause: Improper input validation or boundary checking in the mat_join2 function when processing complex join conditions or large result sets. An attacker can send a SQL query that forces the component to enter an unexpected state, leading to a crash.

Attack Vector: Remote, unauthenticated (if the database is exposed). The attacker sends a malicious SQL query via the MonetDB client protocol (port 50000 by default).

Impact: Denial of Service – the server becomes unavailable for legitimate users until manually restarted.

Vulnerable vs. Patched Code

Since no patch is available, a direct code comparison is not possible. However, based on the vulnerability description, the vulnerable code likely lacks proper validation of join conditions or result set sizes.

Vulnerable Code (Hypothetical):

// mat_join2.c (v11.49.1)
void mat_join2_process(join_request *req) {
    // No bounds check on req->condition_count
    for (int i = 0; i < req->condition_count; i++) {
        // Process each condition without validation
        process_condition(req->conditions[i]);
    }
}

Patched Code (Hypothetical):

// mat_join2.c (patched)
void mat_join2_process(join_request *req) {
    if (req->condition_count > MAX_CONDITIONS) {
        log_error("Too many join conditions");
        return;
    }
    for (int i = 0; i < req->condition_count; i++) {
        if (!validate_condition(req->conditions[i])) {
            log_error("Invalid join condition");
            return;
        }
        process_condition(req->conditions[i]);
    }
}

Exploitation & Lab Setup

Red Team (Attacker)

Prerequisites:

• MonetDB Server v11.49.1 running and accessible on port 50000.
• Ability to send SQL queries (e.g., via mclient or custom script).

Exploit Steps:

1. Connect to the target MonetDB server.
2. Execute a crafted SQL statement that triggers the mat_join2 vulnerability. Example (hypothetical):

   SELECT * FROM table1 JOIN table2 ON 1=1 AND (SELECT COUNT(*) FROM table3) > 0;
   

   Or a query with deeply nested joins:

   SELECT * FROM t1 JOIN t2 ON t1.id = t2.id JOIN t3 ON t2.id = t3.id ... (repeat 1000 times);
   

3. Observe the server crash or become unresponsive.

Note: No public exploit code is available. The above is a conceptual example.

Blue Team (Defender)

Detection:

• Monitor for unusual SQL queries with excessive JOIN operations or complex conditions.
• Set up network monitoring for connections to port 50000.
• Use the detection rules provided below.

Mitigation:

• Restrict network access to the MonetDB server (firewall rules).
• Implement rate limiting on database connections.
• Apply input validation at the application layer before forwarding queries to MonetDB.

Indicators of Compromise (IOCs)

• Network: Unusual SQL queries with many JOIN clauses or complex conditions sent to port 50000.
• System: MonetDB server process crash logs containing references to mat_join2.
• Logs: Error messages like "FATAL: mat_join2: assertion failed" or "Segmentation fault" in MonetDB logs.
• File: Core dump files generated by the MonetDB process.

Detection Engineering

YARA Rule

rule CVE_2024_57626_MonetDB_DoS {
    meta:
        description = "Detects MonetDB server crash logs related to CVE-2024-57626"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2024-57626"
    strings:
        $s1 = "mat_join2" nocase
        $s2 = "assertion failed" nocase
        $s3 = "Segmentation fault" nocase
        $s4 = "FATAL" nocase
    condition:
        all of ($s1, $s2, $s3, $s4)
}

Sigma Rule

title: MonetDB DoS via mat_join2
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects potential exploitation of CVE-2024-57626 in MonetDB logs
author: Valters IT
date: 2025-04-10
logsource:
    product: monetdb
    service: server
detection:
    selection:
        EventID: 1000  # Example event ID for crash
        Message|contains: 'mat_join2'
    condition: selection
falsepositives:
    - Legitimate complex queries (rare)
level: high

Suricata Rule

alert tcp $EXTERNAL_NET any -> $HOME_NET 50000 (msg:"CVE-2024-57626 MonetDB DoS Attempt"; flow:to_server,established; content:"JOIN"; nocase; content:"SELECT"; nocase; pcre:"/(?:JOIN\s+\w+\s+ON\s+.*){10,}/"; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Isolate the MonetDB server from untrusted networks (firewall rules).
2. Monitor logs for crash patterns related to mat_join2.
3. Apply input validation at the application layer to limit JOIN complexity.

Long-term Fix:

• Wait for an official patch from MonetDB developers. Check the MonetDB GitHub repository or mailing list for updates.
• Consider upgrading to a newer version if available.

Workaround:

• Disable the mat_join2 component if possible (not recommended for production without testing).
• Use a reverse proxy to filter SQL queries.

Report generated by Valters IT DevSecOps AI Assistant