CVE-2026-1627 Overview
CVE-2026-1627 is a cryptographic vulnerability affecting SICK LMS1000 and MRS1000 industrial sensor devices. The vulnerability stems from the use of outdated and weak Message Authentication Code (MAC) algorithms in the device's SSH service. An attacker who can interact with network traffic may exploit this weakness to potentially compromise the integrity of SSH sessions, enabling manipulation of transmitted data.
This vulnerability falls under CWE-327 (Use of a Broken or Risky Cryptographic Algorithm), highlighting the critical importance of maintaining strong cryptographic standards in industrial control system (ICS) environments.
Critical Impact
Attackers with network access could compromise SSH session integrity, potentially manipulating sensor data or commands transmitted to industrial LIDAR devices used in safety-critical automation environments.
Affected Products
- SICK LMS1000 Firmware (all versions)
- SICK LMS1000 Hardware
- SICK MRS1000 Firmware (all versions)
- SICK MRS1000 Hardware
Discovery Timeline
- February 27, 2026 - CVE-2026-1627 published to NVD
- March 5, 2026 - Last updated in NVD database
Technical Details for CVE-2026-1627
Vulnerability Analysis
The vulnerability exists within the SSH service implementation on SICK LMS1000 and MRS1000 devices. These industrial LIDAR sensors utilize SSH for secure remote management and configuration. However, the SSH service supports outdated and cryptographically weak MAC algorithms that fail to provide adequate integrity protection for session data.
MAC algorithms are fundamental to SSH security, ensuring that data transmitted during a session has not been tampered with in transit. When weak MAC algorithms are permitted, an attacker positioned on the network path between an administrator and the device could potentially intercept and modify SSH traffic without detection.
The attack requires network-level access and user interaction (such as an administrator initiating an SSH session), but does not require prior authentication or elevated privileges. Successful exploitation could result in high impacts to both confidentiality and integrity, potentially allowing attackers to intercept sensitive configuration data or inject malicious commands into management sessions.
Root Cause
The root cause of CVE-2026-1627 is the firmware's acceptance of deprecated MAC algorithms in its SSH service configuration. This represents a Use of a Broken or Risky Cryptographic Algorithm (CWE-327) condition. The device firmware was not configured to enforce modern, cryptographically strong MAC algorithms, leaving the SSH service vulnerable to integrity attacks when weak algorithms are negotiated during session establishment.
Industrial devices often retain legacy cryptographic options for backward compatibility, but this practice introduces significant security risks when stronger alternatives are not enforced.
Attack Vector
The attack vector is network-based, requiring the attacker to position themselves on the network path between the legitimate user and the target device. The exploitation scenario typically involves:
- The attacker gains network access to the same network segment as the target SICK sensor device
- An administrator initiates an SSH connection to the device for management purposes
- The attacker intercepts the SSH negotiation and forces the use of weak MAC algorithms
- With weak integrity protection in place, the attacker can manipulate transmitted data without detection
- The attacker may then intercept configuration data or inject malicious commands
Since no public proof-of-concept exploit is currently available, the vulnerability primarily poses a risk in environments where network access controls are insufficient.
Detection Methods for CVE-2026-1627
Indicators of Compromise
- Unexpected SSH connections to LMS1000 or MRS1000 devices from unrecognized IP addresses
- SSH session negotiations that result in weak MAC algorithm selection (e.g., hmac-md5, hmac-sha1, hmac-sha1-96)
- Unusual configuration changes on affected devices without corresponding authorized change requests
- Network traffic anomalies suggesting man-in-the-middle positioning near industrial sensor networks
Detection Strategies
- Implement network monitoring to identify SSH connections to affected SICK devices and alert on connections from unauthorized sources
- Configure IDS/IPS rules to detect SSH negotiation traffic specifying weak MAC algorithms
- Deploy network traffic analysis to identify potential man-in-the-middle attacks on OT network segments
- Review SSH connection logs on network devices for connections to affected sensor hardware
Monitoring Recommendations
- Establish baseline SSH traffic patterns to and from SICK LMS1000 and MRS1000 devices for anomaly detection
- Monitor for changes to device configurations through out-of-band verification methods
- Implement centralized logging for all SSH connections to ICS/OT assets with real-time alerting
- Conduct regular vulnerability scans focusing on cryptographic configuration of industrial devices
How to Mitigate CVE-2026-1627
Immediate Actions Required
- Review and apply the latest firmware updates from SICK for LMS1000 and MRS1000 devices
- Implement network segmentation to isolate affected devices from untrusted networks
- Restrict SSH access to affected devices to only authorized management stations using network access control lists
- Consider disabling SSH if not required for operations and using alternative secure management methods
Patch Information
SICK has released security advisory SCA-2026-0005 addressing this vulnerability. Administrators should consult the SICK CSAF PDF Advisory #sca-2026-0005 for detailed patch information and firmware update instructions. Additional guidance is available through the SICK PSIRT Resource page.
Organizations should also review the SICK Cybersecurity Operating Guidelines for comprehensive security hardening recommendations.
Workarounds
- Implement strict network access controls to limit SSH access to only trusted management workstations via firewall rules or VLANs
- Deploy a jump host or bastion server for all SSH management of affected devices, ensuring strong cryptographic configurations on the intermediary
- Enable network monitoring and alerting for any SSH connections to affected devices
- Follow CISA ICS Recommended Practices for securing industrial control system environments
# Network segmentation example - restrict SSH access to management VLAN only
# Example firewall rule (adapt to your specific firewall platform)
iptables -A INPUT -p tcp --dport 22 -s 10.10.50.0/24 -d 10.10.100.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 22 -d 10.10.100.0/24 -j DROP
# Where 10.10.50.0/24 is the management VLAN and 10.10.100.0/24 contains SICK devices
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
