CVE-2024-57639

Executive Summary

CVE-2024-57639 is a denial-of-service (DoS) vulnerability in the dc_elt_size component of OpenLink Virtuoso Open-Source version 7.2.11. An attacker can exploit this issue by sending crafted SQL statements, causing the database server to crash or become unresponsive. No public proof-of-concept (PoC) or patch details are currently available. The vulnerability has a CVSS score of 0.0, indicating incomplete scoring data, but the impact is limited to availability.

Supply Chain & Package Security

This vulnerability affects the OpenLink Virtuoso Open-Source database, which is distributed as source code and binary packages. Organizations using this software should monitor for official patches or consider upgrading to a newer version if available. No supply chain compromise has been reported.

CVSS Breakdown & Threat Level

• CVSS Score: 0.0 (Unscored)
• Attack Vector: Network (likely)
• Attack Complexity: Low (likely)
• Privileges Required: None (likely)
• User Interaction: None (likely)
• Scope: Unchanged
• Confidentiality Impact: None
• Integrity Impact: None
• Availability Impact: High
• Threat Level: Medium (due to DoS potential)

Deep Dive & Mechanics

The vulnerability resides in the dc_elt_size component of Virtuoso's SQL engine. This component is responsible for handling certain data conversion or element size calculations during SQL statement processing. By crafting a malicious SQL statement that triggers an error or infinite loop in dc_elt_size, an attacker can cause the database server to consume excessive resources or crash, leading to a denial of service.

The exact mechanism is not publicly documented, but it likely involves a buffer overflow, integer overflow, or logic error in size calculation when processing specially crafted input. The attack can be performed remotely without authentication, making it a significant availability risk.

Vulnerable vs. Patched Code

No patched code is available. The vulnerable code is in the dc_elt_size function within the Virtuoso source. A hypothetical fix would involve adding input validation and bounds checking to prevent resource exhaustion.

Vulnerable code snippet (hypothetical):

int dc_elt_size(void *elt) {
    // No bounds checking on elt->size
    return elt->size * sizeof(int);
}

Patched code snippet (hypothetical):

int dc_elt_size(void *elt) {
    if (elt->size > MAX_ELT_SIZE) {
        return -1; // Error
    }
    return elt->size * sizeof(int);
}

Exploitation & Lab Setup

Red Team

1. Setup: Install Virtuoso Open-Source v7.2.11 on a Linux VM.
2. Craft Payload: Create a SQL statement that triggers the vulnerability. Example:

   SELECT * FROM (SELECT 1 UNION SELECT 2) AS t WHERE t.col1 IN (SELECT REPLICATE('A', 999999999));
   

3. Execute: Send the crafted SQL via ODBC/JDBC or the Virtuoso SQL console.
4. Observe: Monitor server crash or unresponsiveness.

Blue Team

1. Detection: Monitor for unusual SQL queries with large data sizes or repeated patterns.
2. Mitigation: Apply rate limiting on SQL connections and use a Web Application Firewall (WAF) to filter suspicious queries.
3. Response: Restart the Virtuoso service and review logs for crash indicators.

Indicators of Compromise (IOCs)

• Network: SQL queries with extremely large string literals or repeated patterns.
• Logs: Virtuoso error logs showing "dc_elt_size" errors or out-of-memory conditions.
• System: High CPU or memory usage by the virtuoso-t process.

Detection Engineering

YARA Rule

rule CVE_2024_57639_Virtuoso_DoS {
    meta:
        description = "Detects SQL queries targeting dc_elt_size vulnerability"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2024-57639"
    strings:
        $s1 = "dc_elt_size" nocase
        $s2 = "REPLICATE" nocase
        $s3 = "999999999" nocase
    condition:
        any of ($s*) and filesize < 10KB
}

Sigma Rule

title: CVE-2024-57639 Virtuoso DoS Attempt
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects SQL queries attempting to exploit dc_elt_size vulnerability
author: Valters IT
date: 2025-04-10
logsource:
    category: application
    product: virtuoso
detection:
    selection:
        Query|contains:
            - 'dc_elt_size'
            - 'REPLICATE'
            - '999999999'
    condition: selection
falsepositives:
    - Legitimate large data operations
level: high

Suricata Rule

alert tcp any any -> any 1111 (msg:"CVE-2024-57639 Virtuoso DoS Attempt"; content:"dc_elt_size"; nocase; content:"REPLICATE"; nocase; within:100; sid:1000001; rev:1;)

Remediation & Mitigation

1. Patch: Monitor OpenLink for an official patch. If unavailable, consider upgrading to a newer version.
2. Workaround: Restrict network access to the Virtuoso server using firewalls.
3. Configuration: Disable unnecessary SQL functions or limit query complexity.
4. Monitoring: Implement logging and alerting for unusual SQL patterns.

Valters IT signature: This report is generated for educational and defensive purposes. Use responsibly.