SIMATIC CN 4100: Use of Default Credentials
CVE-2023-49621 is a critical-severity use of default credentials vulnerability in SIMATIC CN 4100 from Siemens, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected SIMATIC CN 4100 versions: All versions < V2.7. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.6% chance of exploitation within 30 days, which is low compared with other CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Update Simatic Cn 4100 Firmware to 2.7 or a later version.
- Read the advisory on cert-portal.siemens.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Siemens | SIMATIC CN 4100 | All versions < V2.7 | Not stated |
| Siemens | Simatic Cn 4100 Firmware | before 2.7 | 2.7 |
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
- NetworkCan be exploited remotely over a network, including the internet.
- 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
- UnchangedImpact stays within the vulnerable component.
- 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:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by CNA (siemens.com).
Official description
A vulnerability has been identified in SIMATIC CN 4100 (All versions < V2.7). The "intermediate installation" system state of the affected application uses default credential with admin privileges. An attacker could use the credentials to gain complete control of the affected device.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Use of Default Credentials
The product uses default credentials (such as passwords or cryptographic keys) for potentially critical functionality.
How developers prevent this class of flaw
- Prohibit use of default, hard-coded, or other values that do not vary for each installation of the product - especially for separate organizations.
- Force the administrator to change the credential upon installation.
- The product administrator could change the defaults upon installation or during operation.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, 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
Recent Use of Default Credentials vulnerabilities
- 9.8 Critical severity
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