CVE-2023-39475: Ignition Deserialization RCE Vulnerability

CVE-2023-39475 Overview

CVE-2023-39475 is a critical insecure deserialization vulnerability affecting Inductive Automation Ignition, a widely deployed industrial automation platform used for SCADA systems and human-machine interfaces (HMI). This vulnerability allows remote attackers to execute arbitrary code on affected installations without requiring authentication, making it particularly dangerous in industrial control system (ICS) environments.

The vulnerability exists within the ParameterVersionJavaSerializationCodec class, where improper validation of user-supplied data enables deserialization of untrusted data. Successful exploitation allows an attacker to execute code in the context of SYSTEM, providing complete control over the affected system.

Critical Impact

Unauthenticated remote code execution with SYSTEM privileges in industrial automation environments poses severe risks to operational technology (OT) infrastructure and could enable attackers to manipulate industrial processes.

Affected Products

• Inductive Automation Ignition (all versions prior to patched release)
• Industrial automation systems utilizing Ignition for SCADA/HMI functionality
• Enterprise deployments of Ignition platform services

Discovery Timeline

• 2024-05-03 - CVE-2023-39475 published to NVD
• 2025-03-13 - Last updated in NVD database

Technical Details for CVE-2023-39475

Vulnerability Analysis

This vulnerability is classified as CWE-502: Deserialization of Untrusted Data. The flaw resides in the ParameterVersionJavaSerializationCodec class, which is responsible for handling serialized Java objects within the Ignition platform.

The core issue stems from the application accepting and deserializing Java objects from network inputs without implementing proper validation or filtering of the incoming data. Java deserialization vulnerabilities are particularly dangerous because they can allow attackers to instantiate arbitrary objects and invoke methods during the deserialization process, leading to code execution.

In this case, the vulnerability is network-accessible and requires no authentication, significantly lowering the barrier to exploitation. The attack complexity is low, meaning no special conditions or configurations are needed beyond network access to the vulnerable service.

Root Cause

The root cause is the absence of proper validation mechanisms for user-supplied serialized data in the ParameterVersionJavaSerializationCodec class. When the application deserializes incoming data, it fails to:

1. Validate the source of the serialized data
2. Implement allowlisting for acceptable classes during deserialization
3. Sanitize or filter potentially malicious serialized objects

This oversight allows attackers to craft malicious serialized payloads containing gadget chains that execute arbitrary code when deserialized by the vulnerable component.

Attack Vector

The attack vector is network-based, allowing remote exploitation without authentication. An attacker can target the Ignition service by sending specially crafted serialized Java objects to the vulnerable endpoint.

The exploitation flow involves:

1. The attacker identifies a network-accessible Ignition installation
2. A malicious serialized payload is crafted using known Java deserialization gadget chains
3. The payload is transmitted to the vulnerable ParameterVersionJavaSerializationCodec component
4. The server deserializes the malicious object, triggering code execution
5. The attacker gains SYSTEM-level access to the underlying host

Since no code examples are available from verified sources, technical exploitation details can be found in the Zero Day Initiative Advisory ZDI-23-1047.

Detection Methods for CVE-2023-39475

Indicators of Compromise

• Unexpected network connections to Ignition services from unknown or external IP addresses
• Anomalous Java process behavior including unusual child process spawning
• Unusual SYSTEM-level process execution originating from the Ignition service
• Suspicious serialized Java object traffic patterns in network logs

Detection Strategies

• Monitor network traffic for serialized Java object patterns targeting Ignition services
• Implement application-level logging to detect deserialization attempts with unexpected class types
• Deploy network intrusion detection signatures for known Java deserialization attack patterns
• Utilize endpoint detection to identify anomalous code execution from the Ignition process

Monitoring Recommendations

• Enable verbose logging on Ignition servers to capture deserialization events
• Monitor for process creation events where the parent process is the Ignition service
• Implement network segmentation monitoring to detect lateral movement from compromised ICS systems
• Track authentication failures and anomalous access patterns to Ignition endpoints

How to Mitigate CVE-2023-39475

Immediate Actions Required

• Isolate affected Ignition installations from untrusted networks immediately
• Implement network segmentation to restrict access to Ignition services to authorized systems only
• Apply vendor-supplied patches as soon as they are available
• Audit system logs for evidence of exploitation attempts

Patch Information

Organizations should consult Inductive Automation for official security patches addressing CVE-2023-39475. The vulnerability was tracked by the Zero Day Initiative as ZDI-CAN-20290 and published as ZDI-23-1047. Contact Inductive Automation support for the latest patched version of Ignition that addresses this deserialization vulnerability.

Workarounds

• Restrict network access to Ignition services using firewall rules to allow only trusted IP addresses
• Place Ignition servers behind a VPN or other secure access gateway
• Implement network-level filtering to block potentially malicious serialized Java traffic
• Consider deploying a web application firewall (WAF) with Java deserialization attack detection capabilities

# Example firewall configuration to restrict Ignition access
# Restrict access to Ignition default ports from untrusted networks
iptables -A INPUT -p tcp --dport 8088 -s 10.0.0.0/8 -j ACCEPT
iptables -A INPUT -p tcp --dport 8088 -j DROP
iptables -A INPUT -p tcp --dport 8043 -s 10.0.0.0/8 -j ACCEPT
iptables -A INPUT -p tcp --dport 8043 -j DROP