OTPulse

Siemens SINEC Network Management System Logback Component

MonitorCVSS 6.6ICS-CERT ICSA-22-314-03Nov 8, 2022
Siemens
Attack path
Attack VectorNetwork
Auth RequiredHigh
ComplexityHigh
User InteractionNone needed
Summary

SINEC NMS versions before 1.0.3 contain a vulnerability in the logback component (CVE-2021-42550) that allows attackers with write access to the logback.xml configuration file to execute arbitrary code on the management system. The vulnerability stems from insecure deserialization in the logback component. Exploitation requires the attacker to already have write access to the configuration file, which is a high-complexity prerequisite. No known public exploits target this vulnerability. Siemens has released version 1.0.3 with a fix.

What this means
What could happen
An attacker with write access to the logback configuration file on SINEC NMS could execute arbitrary code on the management system, potentially allowing them to alter network management functions, disable monitoring, or pivot to other industrial systems.
Who's at risk
This affects organizations running Siemens SINEC NMS (network management system) in versions before 1.0.3. SINEC NMS is used to manage and monitor industrial control system networks and assets. Impacts water utilities, power distribution, manufacturing plants, and other facilities that depend on centralized network management for their automation infrastructure.
How it could be exploited
An attacker must first gain write access to the logback.xml configuration file on a SINEC NMS system. This could occur if the attacker has local system access, compromised credentials with file system permissions, or exploits another vulnerability to gain file write capability. Once the configuration file is modified, the attacker can inject malicious code that executes when the logback logging component processes the configuration.
Prerequisites
  • Write access to logback.xml configuration file
  • Local or local-network access to the SINEC NMS system
  • Engineering or administrative credentials
  • High privilege level on the system
High attack complexityRequires privileged write access to configuration filesAffects network management system which controls visibility and operations across ICSComponent vulnerability (logback) in third-party library
Exploitability
Some exploitation risk — EPSS score 2.7%
Affected products (1)
ProductAffected VersionsFix Status
SINEC NMS<V1.0.31.0.3
Remediation & Mitigation
0/4
Do now
0/1
WORKAROUNDRestrict write access to the logback.xml configuration file to only trusted personnel and service accounts
Schedule — requires maintenance window
0/1

Patching may require device reboot — plan for process interruption

HOTFIXUpdate SINEC NMS to version 1.0.3 or later
Long-term hardening
0/2
HARDENINGPlace SINEC NMS behind a firewall and isolate the network management subnet from business networks and the Internet
HARDENINGImplement network access controls to limit which systems can reach SINEC NMS
View full CISA ICS-CERT advisory
API: /api/v1/advisories/731bcaef-e522-4291-ab88-66c77aae0ced

Get OT security insights every Tuesday

Advisory breakdowns, a weekly summary, and incident analyses for the people actually defending OT environments. Free, no account required.