CVE-2023-1935: Emerson ROC809 Auth Bypass Vulnerability

CVE-2023-1935 Overview

CVE-2023-1935 is a critical authentication bypass vulnerability affecting Emerson ROC800-Series Remote Terminal Unit (RTU) devices. These industrial control system (ICS) devices are commonly deployed in oil and gas, water/wastewater, and other critical infrastructure sectors for remote monitoring and control operations. The vulnerability allows unauthenticated attackers to bypass authentication mechanisms, potentially gaining unauthorized access to sensitive operational data or taking control of the device, which could result in denial-of-service conditions.

Critical Impact

This authentication bypass vulnerability in Emerson ROC800-Series RTU devices could allow attackers to gain unauthorized access to critical industrial control systems, manipulate operational data, or disrupt essential infrastructure services.

Affected Products

• Emerson ROC809 Firmware
• Emerson ROC827 Firmware
• Emerson ROC809L Firmware
• Emerson ROC827L Firmware
• Emerson DL8000 Firmware

Discovery Timeline

• August 2, 2023 - CVE-2023-1935 published to NVD
• November 21, 2024 - Last updated in NVD database

Technical Details for CVE-2023-1935

Vulnerability Analysis

This vulnerability is classified as CWE-287 (Improper Authentication), indicating a fundamental flaw in how the affected devices validate user credentials or session tokens. The authentication bypass allows remote attackers to access device functionality without providing valid credentials, effectively circumventing the security controls designed to protect these industrial control systems.

The vulnerability is exploitable over the network without requiring any user interaction or prior authentication. Once exploited, attackers can potentially read sensitive configuration data, modify device settings, issue commands to connected equipment, or cause service disruptions. Given the role of ROC800-Series devices in critical infrastructure environments, successful exploitation could have significant operational and safety implications.

Root Cause

The root cause of CVE-2023-1935 stems from improper authentication mechanisms within the ROC800-Series firmware. The authentication implementation fails to adequately verify user identity before granting access to protected functions, allowing attackers to bypass security controls entirely. This type of flaw typically occurs when authentication logic can be circumvented through specific request patterns, missing session validation, or flaws in the credential verification process.

Attack Vector

The attack vector for this vulnerability is network-based, meaning attackers can exploit it remotely if they have network access to the affected RTU devices. In typical industrial deployments, RTU devices may be accessible through operational technology (OT) networks, and in some cases through interconnections with corporate IT networks or via remote access pathways.

Attackers targeting these devices would typically:

1. Identify exposed ROC800-Series devices through network scanning
2. Craft requests that bypass the authentication mechanism
3. Gain unauthorized access to device functions and data
4. Potentially modify configurations, exfiltrate data, or disrupt operations

For detailed technical information, refer to the CISA ICS Advisory ICSA-23-206-03.

Detection Methods for CVE-2023-1935

Indicators of Compromise

• Unexpected network connections to ROC800-Series devices from unauthorized IP addresses
• Anomalous authentication events or missing authentication logs for successful device access
• Unauthorized configuration changes to RTU devices without corresponding valid user sessions
• Unusual command or query patterns directed at affected devices

Detection Strategies

• Implement network traffic monitoring and anomaly detection for OT network segments containing ROC800-Series devices
• Deploy intrusion detection systems (IDS) configured with rules to detect authentication bypass attempts against industrial control protocols
• Enable comprehensive logging on all ROC800-Series devices and forward logs to a centralized SIEM for correlation and analysis
• Monitor for unauthorized access patterns or configuration changes through asset inventory and change management systems

Monitoring Recommendations

• Establish baseline network behavior for ROC800-Series devices and alert on deviations
• Implement real-time monitoring of authentication events and access attempts to critical OT assets
• Deploy SentinelOne Singularity for OT/IoT environments to provide visibility into ICS device communications
• Conduct regular security assessments and vulnerability scans of industrial control system networks

How to Mitigate CVE-2023-1935

Immediate Actions Required

• Review the CISA ICS Advisory ICSA-23-206-03 for specific remediation guidance from the vendor
• Ensure affected ROC800-Series devices are not directly accessible from the internet or untrusted networks
• Implement network segmentation to isolate industrial control systems from corporate IT networks
• Apply any available firmware updates or patches from Emerson as soon as possible

Patch Information

Organizations should consult Emerson directly and review the CISA ICS Advisory ICSA-23-206-03 for specific patch information and firmware update recommendations. Contact Emerson technical support for guidance on obtaining and applying security updates for affected ROC809, ROC827, ROC809L, ROC827L, and DL8000 devices.

Workarounds

• Implement strict network access controls and firewall rules to limit connectivity to ROC800-Series devices to authorized systems only
• Use VPN connections with strong authentication for any remote access to OT networks containing affected devices
• Enable and monitor all available logging and auditing features on affected RTU devices
• Consider deploying additional authentication mechanisms such as jump servers or privileged access management solutions for administrative access

# Example firewall rule to restrict access to ROC800 devices (adjust IP ranges as needed)
# Allow only authorized management station
iptables -A INPUT -p tcp -s 10.10.10.100 -d 10.20.30.40 --dport 10001 -j ACCEPT
# Deny all other access to the RTU device
iptables -A INPUT -p tcp -d 10.20.30.40 --dport 10001 -j DROP