CVE-2025-6445: ServiceStack FindType RCE Vulnerability

CVE-2025-6445 Overview

CVE-2025-6445 is a directory traversal vulnerability in ServiceStack that enables remote code execution through the FindType method. This vulnerability allows remote attackers to execute arbitrary code on affected installations of ServiceStack due to the lack of proper validation of user-supplied paths prior to using them in file operations. While interaction with the ServiceStack library is required to exploit this vulnerability, attack vectors may vary depending on the specific implementation.

Critical Impact

Remote attackers can leverage this directory traversal flaw to execute arbitrary code in the context of the current process, potentially leading to complete system compromise.

Affected Products

• ServiceStack (all versions prior to patched release)

Discovery Timeline

• 2025-06-25 - CVE-2025-6445 published to NVD
• 2025-08-08 - Last updated in NVD database

Technical Details for CVE-2025-6445

Vulnerability Analysis

This vulnerability (tracked as ZDI-CAN-25837) exists within the implementation of the FindType method in ServiceStack. The core issue stems from CWE-22 (Path Traversal), where user-supplied input is not properly validated before being used in file system operations. This improper validation allows attackers to craft malicious path inputs that traverse outside intended directories, ultimately enabling arbitrary code execution within the context of the running process.

The network-based attack vector means exploitation can occur remotely, though the complexity is elevated due to implementation-specific requirements. No user interaction or authentication is required for exploitation, making this a particularly dangerous vulnerability for exposed ServiceStack deployments.

Root Cause

The root cause is improper input validation in the FindType method. The method fails to sanitize user-supplied path parameters, allowing directory traversal sequences (such as ../) to escape the intended directory context. This lack of path canonicalization enables attackers to reference arbitrary files on the file system, which can be leveraged for code execution.

Attack Vector

The vulnerability is exploited through network-accessible endpoints that utilize the vulnerable FindType method. An attacker can submit specially crafted path values containing directory traversal sequences to manipulate file operations. When the application processes these malicious paths without proper validation, the attacker gains the ability to:

1. Access files outside the intended directory structure
2. Load arbitrary code or assemblies into the application context
3. Execute code with the privileges of the running ServiceStack process

The exploitation mechanics depend on the specific ServiceStack implementation, but the fundamental issue of path traversal enables attackers to escape directory boundaries and potentially execute malicious payloads. For detailed technical information, refer to the Zero Day Initiative Advisory ZDI-25-416.

Detection Methods for CVE-2025-6445

Indicators of Compromise

• Unusual file access patterns attempting to traverse parent directories (e.g., ../ sequences in request parameters)
• Unexpected file system access logs showing reads or writes outside of expected application directories
• Anomalous process execution spawned from the ServiceStack application process
• Web requests to ServiceStack endpoints containing path traversal sequences in type parameters

Detection Strategies

• Implement web application firewall (WAF) rules to detect and block path traversal patterns in HTTP requests
• Monitor ServiceStack application logs for suspicious FindType method invocations with unusual path parameters
• Deploy endpoint detection and response (EDR) solutions to identify anomalous code execution from the ServiceStack process
• Use file integrity monitoring (FIM) to detect unauthorized file access or modifications

Monitoring Recommendations

• Enable verbose logging for ServiceStack applications to capture detailed request parameters
• Configure alerts for any file system access attempts outside designated application directories
• Monitor process trees for unexpected child processes spawned by the ServiceStack application
• Implement network traffic analysis to identify exploitation attempts targeting ServiceStack endpoints

How to Mitigate CVE-2025-6445

Immediate Actions Required

• Update ServiceStack to the latest patched version immediately
• Review and audit all ServiceStack implementations in your environment
• Implement input validation and path sanitization at the application layer as a defense-in-depth measure
• Restrict network access to ServiceStack endpoints where possible

Patch Information

ServiceStack has addressed this vulnerability in version 8.06. Organizations should update to this version or later to remediate CVE-2025-6445. Refer to the ServiceStack Vulnerabilities Report for official patch information and release notes.

Workarounds

• Implement application-level input validation to sanitize all user-supplied path inputs before they reach the FindType method
• Deploy a web application firewall (WAF) with rules to block directory traversal patterns
• Restrict file system permissions for the ServiceStack process to limit the impact of successful exploitation
• Consider implementing allowlist-based type resolution to prevent arbitrary type lookups

# Example: WAF rule pattern to block directory traversal attempts
# Add to your web application firewall configuration
# Block requests containing path traversal sequences
SecRule REQUEST_URI|ARGS|ARGS_NAMES "@rx \.\./" \
    "id:100001,phase:2,deny,status:403,msg:'Directory Traversal Attempt Blocked'"