CVE-2023-7339: Softing Industrial Gateway Buffer Overflow

CVE-2023-7339 Overview

CVE-2023-7339 is a stack-based buffer overflow vulnerability affecting multiple industrial gateway products manufactured by Softing Industrial Automation GmbH. This memory corruption flaw allows attackers to overflow buffers on the stack, potentially leading to denial of service conditions in critical industrial control system (ICS) environments.

The vulnerability impacts several gateway devices used in industrial automation networks, including PROFINET, EtherNet/IP, Modbus, and PROFIBUS communication gateways. These devices serve as critical infrastructure components that facilitate communication between different industrial protocols, making this vulnerability particularly concerning for operational technology (OT) environments.

Critical Impact

Authenticated network attackers can exploit this stack-based buffer overflow to crash affected industrial gateways, disrupting communication between industrial control systems and potentially causing operational downtime in manufacturing and process control environments.

Affected Products

• Softing pnGate through version 1.30
• Softing epGate through version 1.30
• Softing mbGate through version 1.30
• Softing smartLink HW-DP through version 1.30
• Softing smartLink HW-PN through version 1.01

Discovery Timeline

• 2026-03-27 - CVE-2023-7339 published to NVD
• 2026-03-30 - Last updated in NVD database

Technical Details for CVE-2023-7339

Vulnerability Analysis

This vulnerability is classified as CWE-121 (Stack-based Buffer Overflow), a memory corruption vulnerability that occurs when an application writes more data to a stack-allocated buffer than it can hold. In the context of Softing industrial gateways, this flaw enables attackers with low-level privileges to trigger a buffer overflow condition via network-based requests.

The vulnerability requires network access and low privileges to exploit, with no user interaction necessary. While the scope is unchanged (meaning the vulnerable component and impacted component are the same), the primary impact is on availability—the gateway can be crashed, causing a denial of service condition that disrupts industrial communications.

Industrial gateways like those affected by this vulnerability serve as protocol translators in manufacturing and process control environments. When these devices become unavailable due to a crash, communication between PLCs, HMIs, SCADA systems, and other industrial equipment can be severed, potentially halting production lines or causing safety concerns in critical infrastructure.

Root Cause

The root cause of CVE-2023-7339 is insufficient bounds checking when processing input data that is copied to a stack-allocated buffer. The affected firmware does not properly validate the length of incoming data before performing memory operations, allowing an attacker to provide maliciously crafted input that exceeds the buffer's allocated size.

When the oversized data is written to the stack buffer, it overwrites adjacent memory regions including potentially critical stack frame data such as return addresses and saved registers. In this case, the overflow results in a crash condition rather than code execution, causing the device to become unresponsive.

Attack Vector

The attack vector for this vulnerability is network-based, meaning an attacker must have network connectivity to the vulnerable gateway device. The attack requires low privileges, suggesting that some form of authentication is necessary, but not administrative access.

In typical industrial network architectures, these gateway devices may be accessible from both the IT network and the OT network, depending on network segmentation practices. An attacker who has gained initial access to the industrial network—either through compromised credentials, insider access, or lateral movement from IT systems—could target these gateways to disrupt operations.

The exploitation mechanism involves sending specially crafted network packets or requests to the gateway that contain oversized data fields. When the gateway processes this malicious input, the stack-based buffer overflow is triggered, causing the device to crash and become unavailable until manually restarted.

Detection Methods for CVE-2023-7339

Indicators of Compromise

• Unexpected gateway device crashes or restarts without administrative intervention
• Abnormal network traffic patterns targeting gateway management interfaces or industrial protocols
• Log entries indicating malformed requests or buffer-related errors prior to device failure
• Communication failures between industrial systems that rely on the affected gateway devices

Detection Strategies

• Implement deep packet inspection (DPI) rules to identify malformed or oversized packets targeting Softing gateway protocols
• Configure SIEM correlation rules to alert on repeated gateway device crashes or restarts
• Deploy network-based intrusion detection systems (IDS) with signatures for industrial protocol anomalies
• Monitor for unusual authentication attempts against gateway management interfaces

Monitoring Recommendations

• Enable comprehensive logging on affected gateway devices and forward logs to a centralized security monitoring platform
• Establish baseline behavior for gateway device performance and availability metrics to detect anomalies
• Implement network traffic analysis for communication between gateways and connected industrial systems
• Configure automated alerts for gateway device health status changes

How to Mitigate CVE-2023-7339

Immediate Actions Required

• Identify all Softing pnGate, epGate, mbGate, smartLink HW-DP, and smartLink HW-PN devices in your environment and inventory their firmware versions
• Implement network segmentation to restrict access to gateway devices from untrusted network segments
• Verify that authentication is enabled and configured with strong credentials on all affected devices
• Review firewall rules to limit network access to gateway management interfaces to authorized personnel only

Patch Information

Organizations should consult the official Softing security advisory for firmware update information. The Softing CVE-2023-7339 Advisory provides details on remediation steps and updated firmware versions that address this vulnerability. Additional technical details are available in the Softing CVE-2023-7339 JSON Details.

Contact Softing Industrial Automation GmbH for the latest firmware releases that patch this vulnerability. Given the industrial nature of these devices, coordinate patching activities with operational teams to minimize disruption to production systems.

Workarounds

• Isolate affected gateway devices on dedicated network segments with strict access controls until patches can be applied
• Implement allowlist-based firewall rules to permit only known, trusted IP addresses to communicate with gateway devices
• Deploy network-level rate limiting to mitigate the impact of potential exploitation attempts
• Consider deploying inline industrial protocol filtering appliances to validate traffic before it reaches vulnerable gateways

# Example firewall rule to restrict gateway access (adjust for your environment)
# Limit access to gateway management interface to specific admin workstations
iptables -A INPUT -p tcp --dport 443 -s 10.10.10.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -j DROP