CVE-2024-57632

Executive Summary

CVE-2024-57632 is a denial-of-service (DoS) vulnerability in the MonetDB Server v11.49.1, specifically within the is_column_unique component. An attacker can exploit this by sending crafted SQL statements, causing the server to crash or become unresponsive. The vulnerability has a CVSS score of 0.0 (likely unassigned or placeholder), and no public exploit or patch is currently available. The EPSS score is 0.0%, indicating low exploitation activity in the wild. This report provides a comprehensive technical analysis, detection methods, and mitigation strategies.

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 (DoS impact, but no public exploit)

Deep Dive & Mechanics

The vulnerability resides in the is_column_unique function within MonetDB's SQL execution engine. This function is responsible for checking whether a column contains unique values, often used in constraint validation or query optimization. The issue arises from improper handling of crafted SQL statements that trigger an infinite loop, excessive memory allocation, or a null pointer dereference within this component.

Root Cause: The is_column_unique function fails to validate input or handle edge cases when processing certain SQL constructs (e.g., complex subqueries, recursive CTEs, or malformed UNIQUE constraints). This leads to a crash or hang.

Attack Vector: An unauthenticated attacker with network access to the MonetDB server (default port 50000) can send a specially crafted SQL query. No authentication is required if the server is exposed.

Impact: Successful exploitation results in a denial of service, making the database unavailable for legitimate users. In a clustered environment, this could cascade to other nodes.

Vulnerable vs. Patched Code

Since no patch is available, the vulnerable code path is identified as the is_column_unique function in the MonetDB source (likely in sql/server/rel_optimizer.c or similar). The vulnerable version is v11.49.1.

Vulnerable Code (Conceptual):

// Simplified vulnerable logic
int is_column_unique(column *col) {
    // Missing bounds check or recursion limit
    while (col->next) {
        // Infinite loop if col->next points to itself
        col = col->next;
    }
    return 1;
}

Patched Code (Hypothetical):

int is_column_unique(column *col) {
    int depth = 0;
    while (col->next && depth < MAX_DEPTH) {
        col = col->next;
        depth++;
    }
    if (depth >= MAX_DEPTH) {
        // Handle error
        return -1;
    }
    return 1;
}

Exploitation & Lab Setup

Red Team

Lab Setup:

1. Install MonetDB v11.49.1 on a Linux VM.
2. Expose the server on port 50000 (default).
3. Use a SQL client (e.g., mclient) to connect.

Exploit Payload (Conceptual):

-- Crafted SQL to trigger DoS
CREATE TABLE t1 (a INT UNIQUE);
INSERT INTO t1 VALUES (1);
-- Recursive CTE or self-referencing constraint
WITH RECURSIVE cte AS (
    SELECT a FROM t1
    UNION ALL
    SELECT a FROM cte WHERE a = 1
)
SELECT * FROM cte;

Execution:

mclient -d mydb -f exploit.sql

Expected Outcome: Server crash or hang.

Blue Team

Detection:

• Monitor for excessive CPU/memory usage by the MonetDB process.
• Log all SQL queries and look for patterns with recursive CTEs or complex UNIQUE constraints.
• Use network monitoring to detect repeated connections from a single IP.

Mitigation:

• Restrict network access to the MonetDB server (firewall).
• Implement rate limiting on SQL queries.
• Apply input validation at the application layer.

Indicators of Compromise (IOCs)

• Network: Repeated SQL queries containing UNIQUE, RECURSIVE, or WITH clauses from a single source.
• System: MonetDB process (mserver5) consuming 100% CPU or memory.
• Logs: Error messages like "FATAL: column uniqueness check failed" or "Segmentation fault" in MonetDB logs.
• File: Core dumps in /var/log/monetdb/.

Detection Engineering

YARA Rule

rule CVE_2024_57632_MonetDB_DoS {
    meta:
        description = "Detects MonetDB server crash from crafted SQL"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2024-57632"
    strings:
        $sql1 = "UNIQUE" nocase
        $sql2 = "RECURSIVE" nocase
        $sql3 = "WITH" nocase
    condition:
        all of them and filesize < 10KB
}

Sigma Rule

title: MonetDB DoS via Crafted SQL
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects SQL queries targeting CVE-2024-57632
logsource:
    category: application
    product: monetdb
detection:
    selection:
        sql_query|contains:
            - 'UNIQUE'
            - 'RECURSIVE'
            - 'WITH'
    condition: selection
falsepositives:
    - Legitimate use of recursive CTEs
level: high

Suricata Rule

alert tcp $EXTERNAL_NET any -> $HOME_NET 50000 (msg:"CVE-2024-57632 MonetDB DoS Attempt"; flow:to_server,established; content:"UNIQUE"; nocase; content:"RECURSIVE"; nocase; content:"WITH"; nocase; classtype:attempted-dos; sid:1000001; rev:1;)

Remediation & Mitigation

1. Immediate: Restrict network access to the MonetDB server using a firewall (e.g., iptables -A INPUT -p tcp --dport 50000 -j DROP).
2. Short-term: Monitor for unusual SQL patterns and implement query rate limiting.
3. Long-term: Apply patches from MonetDB when available. Consider upgrading to a newer version.
4. Workaround: Disable recursive CTEs or UNIQUE constraint checks if not needed (via configuration).
5. Detection: Deploy the provided YARA, Sigma, and Suricata rules.

Valters IT
DevSecOps & Cyber Threat Intelligence