CVE-2025-25034: SugarCRM PHP Object Injection Vulnerability

CVE-2025-25034 Overview

A PHP object injection vulnerability exists in SugarCRM versions prior to 6.5.24, 6.7.13, 7.5.2.5, 7.6.2.2, and 7.7.1.0 due to improper validation of PHP serialized input in the SugarRestSerialize.php script. The vulnerable code fails to sanitize the rest_data parameter before passing it to the unserialize() function, allowing unauthenticated attackers to submit crafted serialized data containing malicious object declarations. This results in arbitrary code execution within the application context.

Notably, although SugarCRM released a prior fix in advisory sugarcrm-sa-2016-001, the patch was incomplete and failed to address some attack vectors. Exploitation evidence was observed by the Shadowserver Foundation on 2024-09-13 UTC, indicating active targeting of vulnerable SugarCRM installations.

Critical Impact

Unauthenticated remote code execution through PHP object injection allows attackers to fully compromise SugarCRM servers without requiring any credentials, potentially exposing sensitive CRM data and enabling lateral movement within corporate networks.

Affected Products

• SugarCRM versions prior to 6.5.24
• SugarCRM versions prior to 6.7.13
• SugarCRM versions prior to 7.5.2.5, 7.6.2.2, and 7.7.1.0

Discovery Timeline

• 2025-06-20 - CVE CVE-2025-25034 published to NVD
• 2025-11-20 - Last updated in NVD database

Technical Details for CVE-2025-25034

Vulnerability Analysis

This vulnerability stems from CWE-502: Deserialization of Untrusted Data. The core issue lies in the insecure handling of user-supplied serialized PHP objects within SugarCRM's REST API. The SugarRestSerialize.php script accepts the rest_data parameter from incoming requests and passes it directly to PHP's native unserialize() function without adequate validation or sanitization.

PHP's unserialize() function is inherently dangerous when processing untrusted input because it automatically instantiates objects based on the serialized data. When an attacker supplies a malicious serialized payload containing specially crafted object declarations, the application will instantiate these objects and execute any magic methods (such as __wakeup(), __destruct(), or __toString()) defined within them.

The presence of a public Metasploit module and the high EPSS score of 69.028% (98.62 percentile) indicates this vulnerability is highly likely to be exploited in the wild. The incomplete nature of the initial patch (sugarcrm-sa-2016-001) demonstrates the complexity of fully mitigating deserialization vulnerabilities.

Root Cause

The root cause is the use of PHP's unserialize() function on untrusted user input without proper validation. The SugarRestSerialize.php script accepts the rest_data parameter from REST API requests and deserializes it without verifying the content against an allowlist of expected object types. This allows attackers to inject arbitrary PHP objects that, when deserialized, trigger malicious code execution through PHP's magic method invocation mechanism.

Attack Vector

The attack is network-based and requires no authentication or user interaction. An attacker crafts a malicious HTTP request to the SugarCRM REST API endpoint, embedding a specially constructed serialized PHP object in the rest_data parameter. The serialized payload typically leverages existing classes within SugarCRM (known as "gadget chains") that have exploitable magic methods.

When the server processes the request and calls unserialize() on the attacker-controlled data, the malicious object is instantiated. The object's destructor or other magic methods then execute attacker-supplied commands within the context of the web server, enabling full server compromise.

The vulnerability is particularly dangerous because it requires no prior knowledge of application credentials and can be exploited by any attacker with network access to the SugarCRM installation. Technical details and proof-of-concept code are available in the Metasploit SugarCRM Exploit module and the Exploit-DB #40344 entry.

Detection Methods for CVE-2025-25034

Indicators of Compromise

• Unusual HTTP POST requests to SugarCRM REST API endpoints containing serialized PHP data patterns (look for O: prefixes followed by object declarations in rest_data parameters)
• Web server logs showing requests to /service/v4/rest.php or similar REST endpoints with abnormally large or suspicious rest_data values
• Evidence of unexpected PHP processes spawning shell commands or network connections from the web server context
• File system modifications in the SugarCRM directory structure, particularly new or modified PHP files that could indicate webshell deployment

Detection Strategies

• Deploy web application firewall (WAF) rules to detect and block serialized PHP object patterns in incoming requests, specifically targeting the O: object notation in POST parameters
• Implement intrusion detection system (IDS) signatures to identify exploitation attempts targeting the SugarCRM REST API deserialization vulnerability
• Monitor SugarCRM application logs for unusual REST API activity, particularly failed requests or errors related to object instantiation
• Use SentinelOne's behavioral detection to identify post-exploitation activities such as command execution or file manipulation originating from web server processes

Monitoring Recommendations

• Enable verbose logging on SugarCRM REST API endpoints and forward logs to a centralized SIEM for correlation and analysis
• Implement network traffic analysis to detect outbound connections from the SugarCRM server that may indicate successful compromise and command-and-control communication
• Set up file integrity monitoring (FIM) on the SugarCRM installation directory to detect unauthorized modifications that could indicate webshell deployment

How to Mitigate CVE-2025-25034

Immediate Actions Required

• Immediately upgrade SugarCRM to version 6.5.24, 6.7.13, 7.5.2.5, 7.6.2.2, 7.7.1.0 or later to address this vulnerability
• If immediate patching is not possible, restrict network access to the SugarCRM REST API endpoints using firewall rules or web server configuration
• Conduct a thorough review of web server logs for evidence of prior exploitation attempts or successful compromise
• Deploy web application firewall rules to block requests containing serialized PHP object patterns in the rest_data parameter

Patch Information

SugarCRM has addressed this vulnerability in security advisory sugarcrm-sa-2016-008, which provides a complete fix for the incomplete patch released in sugarcrm-sa-2016-001. Organizations should upgrade to the following minimum versions:

• Version 6.5.24 for the 6.5.x branch
• Version 6.7.13 for the 6.7.x branch
• Version 7.5.2.5 for the 7.5.x branch
• Version 7.6.2.2 for the 7.6.x branch
• Version 7.7.1.0 for the 7.7.x branch

For detailed patch information, refer to the SugarCRM Security Advisory 2016-008 and the VulnCheck SugarCRM RCE Advisory.

Workarounds

• Implement network-level access controls to restrict access to SugarCRM REST API endpoints to trusted IP addresses only
• Deploy a web application firewall configured to inspect and block HTTP requests containing serialized PHP object patterns (regex pattern: O:\d+:\"[a-zA-Z_])
• Consider disabling the REST API entirely if it is not required for business operations, and use alternative integration methods
• Apply virtual patching through reverse proxy or WAF rules while scheduling the official upgrade

# Example Apache .htaccess rule to block suspicious serialized data
<IfModule mod_rewrite.c>
    RewriteEngine On
    RewriteCond %{QUERY_STRING} rest_data=.*O:\d+: [NC,OR]
    RewriteCond %{REQUEST_BODY} O:\d+: [NC]
    RewriteRule .* - [F,L]
</IfModule>