CVE-2024-27047 Siemens CVE debrief

Who should care

Industrial control system operators, OT security teams, and asset owners deploying Siemens SIMATIC S7-1500 TM MFP systems should prioritize this vulnerability. The kernel-level crash could disrupt critical manufacturing processes, safety systems, or infrastructure operations dependent on these controllers. System integrators and maintenance personnel with shell access to the GNU/Linux subsystem represent a key insider threat vector. Organizations subject to NERC CIP, IEC 62443, or similar OT security frameworks should incorporate this into their vulnerability management programs given the lack of available patches.

Technical summary

The vulnerability resides in the Linux kernel's network PHY (physical layer) driver subsystem, specifically in the `phy_get_internal_delay` function. When this function is invoked without a defined `delay_values` array, and the device tree specifies `rx-internal-delay-ps` or `tx-internal-delay-ps` as 0, the code attempts to index into an empty or uninitialized array. This results in a NULL pointer dereference that crashes the kernel. The issue is classified under CWE-20 (Improper Input Validation). The affected product is the GNU/Linux subsystem within Siemens SIMATIC S7-1500 TM MFP programmable logic controllers, which are used in industrial automation environments. The local attack vector suggests that an attacker with the ability to influence device tree configuration or load malicious kernel modules could trigger the denial-of-service condition.

Defensive priority

medium

Recommended defensive actions

• Restrict access to the interactive shell of the GNU/Linux subsystem to trusted personnel only
• Only build and run applications from trusted sources
• Monitor for kernel panic events indicating NULL pointer dereference at virtual address 0
• Apply defense-in-depth strategies for industrial control systems per CISA guidance
• Subscribe to Siemens security advisories for patch availability updates

Evidence notes

The vulnerability description is derived from the CISA CSAF advisory ICSA-24-102-01, which references Siemens security advisory SSA-265688. The CVSS 3.1 vector AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H indicates a local attack vector with low attack complexity, no privileges required, and high availability impact. The advisory explicitly states 'Currently no fix is available' as of the last modification date.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.