SIMATIC CN 4100: Missing Immutable Root of Trust in Hardware
CVE-2024-32742 is a high-severity missing immutable root of trust in hardware vulnerability in SIMATIC CN 4100 from Siemens, with a CVSS 3.1 base score of 7.6 out of 10. It can be exploited with physical access to the device by an unauthenticated attacker, without any action from a user. The record lists versions V3.0, 3.0 as the first without the flaw, so updating SIMATIC CN 4100 to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.39% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update SIMATIC CN 4100 to V3.0 or 3.0, whichever matches your release line, or a later version.
- Update Simatic Cn 4100 Firmware to 3.0 or a later version.
- Read the advisory on cert-portal.siemens.com for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Siemens | SIMATIC CN 4100 | before V3.0; before 3.0 | V3.0, 3.0 |
| Siemens | Simatic Cn 4100 Firmware | before 3.0 | 3.0 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- PhysicalThe attacker must physically touch the device.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- ChangedThe attack can reach beyond the vulnerable component into other systems.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H. Scored by CNA (siemens.com).
Official description
A vulnerability has been identified in SIMATIC CN 4100 (All versions < V3.0). The affected device contains an unrestricted USB port. An attacker with local access to the device could potentially misuse the port for booting another operating system and gain complete read/write access to the filesystem.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Missing Immutable Root of Trust in Hardware
A missing immutable root of trust in the hardware results in the ability to bypass secure boot or execute untrusted or adversarial boot code.
How developers prevent this class of flaw
- When architecting the system, the RoT should be designated for storage in a memory that does not allow further programming/writes. Note that, for components like ROM, secure patching/update features should be supported to allow authenticated and authorized updates in the field.
- During implementation and test, the RoT memory location should be demonstrated to not allow further programming/writes.
More Missing Immutable Root of Trust in Hardware vulnerabilities (CWE-1326)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Other vulnerabilities in SIMATIC CN 4100
- 7.5 High severity
- 9.1 Critical severity
- 7.8 High severity
- 7.5 High severity
- 9.8 Critical severity
- 7.5 High severity
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