CVE-2025-41222 Overview
CVE-2025-41222 is a denial-of-service vulnerability affecting a wide range of Siemens RUGGEDCOM industrial network devices. The flaw resides in the web server's Transport Layer Security (TLS) handshake handler, which does not properly handle malformed handshake messages. An unauthenticated attacker with network access to the web server can send a crafted TLS handshake to crash both the web server and the underlying device. The vulnerability is classified under CWE-755: Improper Handling of Exceptional Conditions and impacts RUGGEDCOM ROS-based switches and serial devices widely deployed in electric utility substations, transportation systems, and other operational technology (OT) environments.
Critical Impact
Unauthenticated attackers on the network can crash RUGGEDCOM devices, disrupting industrial network communications and requiring device restart.
Affected Products
- RUGGEDCOM ROS-based switches including RSG2100, RSG2200, RSG2288, RSG2300, RSG2488, and RSG920P (V5.X versions prior to V5.10.0)
- RUGGEDCOM RS-series devices including RS400, RS416, RS416v2, RS900, RS900G, RS8000, RS910, RS940G, and RS969 (all versions or V5.X < V5.10.0)
- RUGGEDCOM i800/i801/i802/i803, M2100, M2200, M969, RMC30, RMC8388, RP110, RSL910, RST2228, RST2228P, RST916C, RST916P, and RSG907R/908C/909R/910C series
Discovery Timeline
- 2025-07-08 - CVE-2025-41222 published to the National Vulnerability Database (NVD)
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2025-41222
Vulnerability Analysis
The vulnerability is a denial-of-service condition triggered during TLS handshake processing on the RUGGEDCOM device web server. When the device receives a malformed TLS handshake message, the server fails to handle the exceptional condition and terminates unexpectedly. The crash extends beyond the web service itself, taking down the device and interrupting network switching or routing functions provided by the appliance.
Because RUGGEDCOM devices are frequently deployed in substations, rail signaling, and industrial control networks, a device crash can propagate operational impact upstream. The attack requires only network reachability to the management web interface, with no authentication or user interaction. Confidentiality and integrity are unaffected, but availability of the device and downstream network segments is compromised until the device restarts.
Root Cause
The root cause is improper handling of exceptional conditions ([CWE-755]) in the TLS handshake parser embedded in the RUGGEDCOM web server. Malformed handshake fields, such as invalid record lengths, cipher suite lists, or extension structures, are not gracefully rejected. Instead, the parsing logic reaches an unrecoverable state that terminates the web server process and destabilizes the firmware. This class of bug is common in embedded TLS stacks that lack robust input validation prior to state machine transitions.
Attack Vector
Exploitation is performed remotely over the network by connecting to the HTTPS management port of an affected RUGGEDCOM device. The attacker delivers a crafted TLS ClientHello or subsequent handshake record containing malformed fields. No credentials are needed and no user interaction is required on the device side. Successful exploitation causes the web server to crash and the device to reboot or hang. Refer to the Siemens Security Advisory SSA-083019 for full technical details and affected model coverage.
Detection Methods for CVE-2025-41222
Indicators of Compromise
- Unexpected reboots or unresponsiveness of RUGGEDCOM devices coinciding with inbound HTTPS traffic to the management interface
- TLS handshake failures logged from unusual source addresses targeting device management IPs on TCP port 443
- Loss of network connectivity through affected switches followed by device recovery cycles
Detection Strategies
- Monitor RUGGEDCOM device uptime and syslog output for repeated web server crashes or unplanned restarts
- Inspect network traffic to management interfaces for malformed TLS records using deep packet inspection or IDS signatures targeting anomalous ClientHello structures
- Correlate SNMP trap events indicating device restart with network-layer TLS session anomalies
Monitoring Recommendations
- Baseline expected sources of HTTPS management traffic and alert on connections from unauthorized subnets
- Enable syslog forwarding from RUGGEDCOM devices to a centralized log platform for uptime and TLS error monitoring
- Track patch inventory for firmware versions below V5.10.0 across the RUGGEDCOM fleet
How to Mitigate CVE-2025-41222
Immediate Actions Required
- Upgrade affected RUGGEDCOM devices with V5.X firmware to V5.10.0 or later where available
- Restrict network access to the device web server so only authorized management workstations can reach TCP port 443
- Segment RUGGEDCOM management interfaces onto a dedicated OT management VLAN isolated from general enterprise networks
Patch Information
Siemens has released firmware V5.10.0 addressing this vulnerability for supported RUGGEDCOM V5.X products. Devices in the V4.X branch and end-of-life RUGGEDCOM models listed in the advisory do not have a fix and require compensating controls. Consult the Siemens Security Advisory SSA-083019 for model-specific update guidance.
Workarounds
- Disable the web management interface on affected devices where feasible and manage them via CLI over SSH
- Apply firewall access control lists restricting HTTPS access to trusted management hosts only
- Follow Siemens operational guidelines for securing industrial devices and align with IEC 62443 network segmentation practices
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
