CVE-2024-27419 Siemens CVE debrief

Who should care

Organizations operating Siemens SIMATIC S7-1500 TM MFP systems with enabled GNU/Linux subsystems, particularly in critical infrastructure and industrial automation environments. Security teams responsible for OT/ICS asset protection and kernel-level vulnerability management should prioritize access controls pending vendor fixes.

Technical summary

The vulnerability resides in the Linux kernel's NET/ROM protocol implementation, specifically in the handling of the `sysctl_net_busy_read` sysctl parameter. A data race occurs when the sysctl value is read while being concurrently modified, as the reader lacks proper synchronization protection. This is a local vulnerability requiring low privileges, with no confidentiality or integrity impact but potential high availability impact. The affected product is the GNU/Linux subsystem within Siemens SIMATIC S7-1500 TM MFP industrial controllers. No patch is currently available; mitigation relies on access restrictions and trusted application execution.

Defensive priority

medium

Recommended defensive actions

• Restrict interactive shell access to the GNU/Linux subsystem to trusted personnel only
• Build and run only applications from trusted sources
• Monitor for kernel updates from Siemens when fixes become available
• Apply defense-in-depth strategies for industrial control system environments
• Review CISA ICS recommended practices for additional hardening guidance

Evidence notes

The vulnerability description indicates a classic data race condition in kernel sysctl handling. The NET/ROM protocol (network layer for amateur packet radio) contains insufficient synchronization around the `sysctl_net_busy_read` parameter. Siemens has confirmed this affects the GNU/Linux subsystem of their SIMATIC S7-1500 TM MFP product line. CISA has tracked this through ICSA-24-102-01 with multiple revision updates through 2025-09-09, indicating ongoing monitoring of related kernel vulnerabilities.

Official resources