CVE-2025-27392: Siemens Scalance LPE9403 RCE Vulnerability

CVE-2025-27392 Overview

CVE-2025-27392 is an OS command injection vulnerability [CWE-78] affecting Siemens SCALANCE LPE9403 (6GK5998-3GS00-2AC2) Local Processing Engine devices running firmware versions prior to V4.0. The device fails to properly sanitize user input when creating new Virtual Extensible LAN (VXLAN) configurations. An authenticated attacker with high privileges can inject operating system commands through the affected configuration interface. Successful exploitation allows arbitrary code execution on the underlying device, compromising the confidentiality, integrity, and availability of the industrial edge computing platform.

Critical Impact

An authenticated high-privileged remote attacker can execute arbitrary OS commands on SCALANCE LPE9403 devices, gaining control over an industrial edge platform deployed in operational technology (OT) networks.

Affected Products

• Siemens SCALANCE LPE9403 (6GK5998-3GS00-2AC2) — all firmware versions prior to V4.0
• Siemens SCALANCE LPE9403 hardware platform
• Siemens SCALANCE LPE9403 firmware

Discovery Timeline

• 2025-03-11 - CVE-2025-27392 published to NVD
• 2025-03-11 - Siemens publishes Security Advisory SSA-075201
• 2025-08-25 - Last updated in NVD database

Technical Details for CVE-2025-27392

Vulnerability Analysis

The SCALANCE LPE9403 is a Local Processing Engine designed for edge computing in industrial networks. The device exposes management interfaces that allow administrators to configure overlay networking features, including VXLAN tunnels. The vulnerability resides in the VXLAN configuration handler, which accepts user-supplied parameters and passes them to underlying operating system commands without adequate sanitization.

The Exploit Prediction Scoring System (EPSS) places this issue in the upper percentile range, reflecting elevated exploitation likelihood relative to other published CVEs. Although authentication with high privileges is required, OT environments frequently expose management planes to lateral movement once an initial foothold is established. Compromise of an LPE9403 provides attackers with code execution on an industrial edge node, which often bridges IT and OT segments.

Root Cause

The root cause is improper neutralization of special elements used in an OS command [CWE-78]. Input fields associated with new VXLAN configuration entries are concatenated into shell commands without escaping or argument-array execution. Shell metacharacters such as ;, |, &, and backticks remain unfiltered, enabling command injection at the privilege level of the configuration process.

Attack Vector

The attack vector is network-based and requires authentication as a high-privileged user. After authenticating to the device management interface, the attacker submits a crafted VXLAN configuration request containing injected shell syntax in a controllable parameter. The configuration backend executes the resulting command string, running attacker-controlled code on the device. No user interaction is required beyond authenticated API or web interface access. See the Siemens Security Advisory SSA-075201 for technical details.

Detection Methods for CVE-2025-27392

Indicators of Compromise

• Unexpected processes spawned by the VXLAN or network configuration daemon on the LPE9403
• VXLAN configuration entries containing shell metacharacters such as ;, |, &&, or backticks in name or parameter fields
• Outbound connections from the SCALANCE LPE9403 to unfamiliar IP addresses following configuration changes
• Unauthorized modifications to system files, cron entries, or startup scripts on the device

Detection Strategies

• Audit device configuration logs for VXLAN creation events and review parameter values for non-printable or shell-metacharacter content
• Monitor authentication logs for administrative logins followed immediately by network configuration changes
• Correlate management-plane API calls against expected change-management windows to surface anomalous configuration activity

Monitoring Recommendations

• Forward SCALANCE LPE9403 syslog and audit events to a centralized SIEM for inspection
• Baseline normal VXLAN configuration patterns and alert on deviations in parameter length or character set
• Track administrative account usage on industrial edge devices and alert on logins from unexpected source addresses

How to Mitigate CVE-2025-27392

Immediate Actions Required

• Upgrade SCALANCE LPE9403 firmware to version V4.0 or later as directed by Siemens Security Advisory SSA-075201
• Restrict management interface access to dedicated administrative networks using firewall rules and VLAN segmentation
• Rotate credentials for high-privileged accounts on affected devices and enforce strong, unique passwords
• Inventory all SCALANCE LPE9403 deployments and prioritize patching of internet-exposed or IT/OT boundary devices

Patch Information

Siemens addressed CVE-2025-27392 in SCALANCE LPE9403 firmware V4.0. Administrators should obtain the update through the Siemens Industry Online Support portal and follow the upgrade procedure documented in Siemens Security Advisory SSA-075201.

Workarounds

• Limit access to the device management interface to trusted engineering workstations through network access control lists
• Apply Siemens defense-in-depth guidance for industrial security, including placing devices behind a hardened cell protection firewall
• Restrict VXLAN configuration privileges to a minimal set of administrators and review existing role assignments
• Disable or remove unused administrative accounts on the LPE9403 to reduce the attack surface

# Example: restrict management access to the SCALANCE LPE9403 from an upstream firewall
# Replace <MGMT_NET> with the administrative subnet and <LPE9403_IP> with the device address
iptables -A FORWARD -s <MGMT_NET> -d <LPE9403_IP> -p tcp --dport 443 -j ACCEPT
iptables -A FORWARD -d <LPE9403_IP> -p tcp --dport 443 -j DROP
iptables -A FORWARD -d <LPE9403_IP> -p tcp --dport 22  -j DROP