CVE-2025-27816: Arctera InfoScale RCE Vulnerability

CVE-2025-27816 Overview

A critical insecure deserialization vulnerability has been discovered in Arctera InfoScale versions 7.0 through 8.0.2. The vulnerability exists within the .NET remoting endpoint implementation in the Windows Plugin_Host service, which runs on all servers where InfoScale is installed. An attacker can exploit this flaw by sending specially crafted, malicious serialized objects to the service, potentially achieving remote code execution on vulnerable systems.

The Plugin_Host service is specifically utilized when applications are configured for Disaster Recovery (DR) using the DR wizard. While the service runs by default on all InfoScale installations, it is only actively used in DR configurations, creating an unnecessary attack surface for environments not leveraging DR functionality.

Critical Impact

This vulnerability allows unauthenticated remote attackers to execute arbitrary code on affected systems by exploiting insecure deserialization in the Plugin_Host service, potentially leading to complete system compromise.

Affected Products

• Arctera InfoScale 7.0
• Arctera InfoScale 7.x through 8.0.1
• Arctera InfoScale 8.0.2

Discovery Timeline

• 2025-03-07 - CVE-2025-27816 published to NVD
• 2025-03-07 - Last updated in NVD database

Technical Details for CVE-2025-27816

Vulnerability Analysis

This vulnerability falls under CWE-502 (Deserialization of Untrusted Data), a well-documented class of security flaws that can lead to severe consequences when applications deserialize data from untrusted sources without proper validation.

The core issue lies in the .NET remoting endpoint exposed by the Plugin_Host service. .NET remoting is a legacy technology that enables communication between application domains, processes, or machines. When configured insecurely, these endpoints can accept serialized .NET objects from remote clients and deserialize them without adequate type restrictions or input validation.

In this case, the Plugin_Host service deserializes incoming messages without verifying their origin or validating the object types being deserialized. An attacker can craft malicious serialized objects containing gadget chains—sequences of .NET types that, when deserialized, trigger arbitrary code execution. Common gadget chains leverage types from the .NET Framework itself, such as those found in System.Windows.Data or System.Configuration.Install namespaces.

Root Cause

The root cause is the implementation of .NET remoting with insufficient security controls. The Plugin_Host service accepts serialized .NET objects over the network without implementing type filtering, authentication, or integrity verification. This design flaw allows attackers to inject malicious serialized payloads that execute arbitrary code during the deserialization process.

The vulnerability is exacerbated by the fact that the service runs with elevated privileges on Windows systems, meaning successful exploitation typically grants the attacker high-level access to the compromised host.

Attack Vector

The attack is network-based and requires no authentication or user interaction. An attacker with network access to the Plugin_Host service port can send specially crafted .NET serialized objects to the vulnerable endpoint. The service then deserializes these objects, triggering the execution of attacker-controlled code.

Typical exploitation involves:

1. Identifying systems running the vulnerable Plugin_Host service
2. Crafting a malicious serialized payload using known .NET deserialization gadget chains
3. Sending the payload to the .NET remoting endpoint
4. The service deserializes the payload, executing the embedded malicious code
5. The attacker gains code execution with the privileges of the Plugin_Host service

Tools such as ysoserial.net can be used to generate various .NET deserialization payloads that leverage different gadget chains to achieve code execution. For detailed technical information, refer to the Veritas Security Advisory ARC25-002.

Detection Methods for CVE-2025-27816

Indicators of Compromise

• Unusual network connections to the Plugin_Host service port from external or unexpected internal sources
• Anomalous process spawning from the Plugin_Host service process
• Unexpected child processes created by services running under InfoScale
• Suspicious .NET remoting traffic patterns or large serialized object transfers

Detection Strategies

• Monitor for network traffic to .NET remoting endpoints associated with InfoScale installations
• Implement endpoint detection rules to identify deserialization exploitation attempts and suspicious process genealogy
• Deploy network intrusion detection signatures for known .NET deserialization attack patterns
• Enable Windows process auditing to track child processes spawned by the Plugin_Host service

Monitoring Recommendations

• Audit all systems running Arctera InfoScale to identify the Plugin_Host service status
• Configure SIEM alerts for unusual outbound connections from servers hosting InfoScale
• Monitor Windows Event Logs for service crashes, unexpected restarts, or error events related to Plugin_Host
• Implement file integrity monitoring on critical system directories to detect post-exploitation activities

How to Mitigate CVE-2025-27816

Immediate Actions Required

• Disable the Plugin_Host service on all InfoScale installations not actively using Disaster Recovery functionality
• Apply network segmentation to restrict access to the Plugin_Host service port from untrusted networks
• Review and update firewall rules to limit inbound connections to affected systems
• Prioritize patching for internet-facing or DMZ systems running InfoScale

Patch Information

Arctera has released a security advisory addressing this vulnerability. Organizations should consult the Veritas Security Advisory ARC25-002 for official patch information and remediation guidance. Apply the vendor-provided security updates as soon as they become available for your specific InfoScale version.

Workarounds

• Manually disable the Plugin_Host service on systems where DR functionality is not required using Windows Services management
• Implement host-based firewall rules to block incoming connections to the Plugin_Host service port
• Deploy application whitelisting to prevent unauthorized code execution even if exploitation occurs
• Consider network isolation for systems that must run the vulnerable service until patches can be applied

# Disable Plugin_Host service on Windows (PowerShell)
Stop-Service -Name "Plugin_Host" -Force
Set-Service -Name "Plugin_Host" -StartupType Disabled

# Verify service is disabled
Get-Service -Name "Plugin_Host" | Select-Object Name, Status, StartType