CVE-2020-28328: SuiteCRM RCE Vulnerability

CVE-2020-28328 Overview

CVE-2020-28328 is a Remote Code Execution (RCE) vulnerability affecting SuiteCRM, the open-source Customer Relationship Management platform. The vulnerability exists in the system settings module where the Log File Name configuration parameter can be manipulated by an authenticated attacker to reference an attacker-controlled .php file under the web root, ultimately achieving arbitrary code execution on the server.

This vulnerability is particularly dangerous in scenarios involving admin account compromise, as it provides a direct pathway from administrative access to full server-level code execution, potentially affecting all data and services hosted on the vulnerable system.

Critical Impact

Authenticated attackers can achieve remote code execution by manipulating the logger_file_name setting to point to a malicious PHP file, leading to complete server compromise.

Affected Products

• SuiteCRM versions prior to 7.11.17
• SuiteCRM LTS versions prior to 7.10.28
• salesagility suitecrm

Discovery Timeline

• 2020-11-06 - CVE-2020-28328 published to NVD
• 2024-11-21 - Last updated in NVD database

Technical Details for CVE-2020-28328

Vulnerability Analysis

This vulnerability (CWE-434: Unrestricted Upload of File with Dangerous Type) stems from insufficient validation of the logger_file_name configuration parameter within SuiteCRM's system settings. When an attacker gains access to an admin account (through credential theft, phishing, or other means), they can modify this setting to reference a PHP file path of their choosing.

The attack chain typically involves first uploading a malicious PHP file to a location within the web root, then modifying the log file name setting to point to this file with a .php extension. When the logging mechanism attempts to write to this file, it may inadvertently execute the malicious PHP code, granting the attacker remote code execution capabilities.

The vulnerability has a high exploitation probability with public proof-of-concept exploits available. Multiple exploit variations have been documented on Packet Storm Security targeting different SuiteCRM versions.

Root Cause

The root cause lies in the inadequate input validation and sanitization of the logger_file_name parameter in SuiteCRM's configuration settings. The application fails to properly restrict:

1. The file extension that can be specified for log files
2. The directory path traversal that could allow referencing files outside expected locations
3. Validation that the specified file is actually a legitimate log file and not executable code

This allows an authenticated administrator to configure the logging system to write to or reference arbitrary PHP files, effectively turning a configuration change into a code execution primitive.

Attack Vector

The attack is conducted over the network and requires low-privilege authenticated access (typically administrative credentials). The attack flow proceeds as follows:

1. Attacker obtains administrative access to the SuiteCRM instance through credential compromise or account takeover
2. Attacker uploads a malicious PHP file to a web-accessible directory or identifies an existing writable location
3. Attacker navigates to the system settings and modifies the Log File Name parameter
4. The logger_file_name is set to point to the malicious .php file under the web root
5. When the log file is accessed or processed, the PHP code executes with the web server's privileges

The vulnerability requires no user interaction beyond the attacker's own actions and can result in complete confidentiality, integrity, and availability impact on the affected system. Detailed technical analysis and proof-of-concept code can be found at the GitHub SuiteCRM RCE repository.

Detection Methods for CVE-2020-28328

Indicators of Compromise

• Unusual modifications to SuiteCRM configuration files, particularly config.php or config_override.php with suspicious logger_file_name values
• Presence of unexpected .php files in the SuiteCRM web root or upload directories
• Web server logs showing access to non-standard PHP files that appear to be log-related
• Administrative setting changes to logging configurations without authorized change requests

Detection Strategies

• Monitor changes to the logger_file_name configuration parameter through file integrity monitoring on config files
• Implement alerting for new PHP file creation in the SuiteCRM installation directory
• Review web server access logs for requests to unusual .php files, especially those with log-like naming patterns
• Deploy web application firewall (WAF) rules to detect and block attempts to set suspicious log file paths

Monitoring Recommendations

• Enable comprehensive audit logging for all administrative actions within SuiteCRM
• Implement file integrity monitoring (FIM) on critical configuration files including config.php and config_override.php
• Monitor for PHP file creation events in real-time using endpoint detection solutions
• Set up alerts for configuration changes to the logging subsystem

How to Mitigate CVE-2020-28328

Immediate Actions Required

• Upgrade SuiteCRM to version 7.11.17 or later (or 7.10.28 LTS or later) immediately
• Audit current logger_file_name settings across all SuiteCRM instances for suspicious values
• Review administrative access logs to identify potential unauthorized configuration changes
• Implement additional authentication controls for administrative accounts (MFA)

Patch Information

SalesAgility has released patched versions addressing this vulnerability. Organizations should upgrade to:

• SuiteCRM 7.11.17 or later for the standard release branch
• SuiteCRM 7.10.28 LTS or later for the long-term support branch

Detailed release information is available in the SuiteCRM Release Notes.

Workarounds

• Restrict administrative access to the SuiteCRM instance to only trusted IP addresses via firewall rules
• Implement web application firewall (WAF) rules to block modification attempts to the logger_file_name parameter
• Configure file system permissions to prevent the web server from writing PHP files to the web root
• Disable or restrict access to the system settings page for non-essential administrative users

# Example: Restrict write permissions on SuiteCRM config files
chmod 444 /var/www/suitecrm/config.php
chmod 444 /var/www/suitecrm/config_override.php

# Ensure proper ownership
chown root:www-data /var/www/suitecrm/config.php
chown root:www-data /var/www/suitecrm/config_override.php