Full Report
A vulnerability in SIMATIC CN 4100 could allow an attacker to cause a denial of service condition. Siemens has released a new version for SIMATIC CN 4100 and recommends to update to the latest version.
Analysis Summary
# Vulnerability: Denial of Service in SIMATIC CN 4100 via SFTP File Storage
## CVE Details
- CVE ID: CVE-2025-40593
- CVSS Score: 6.5 (CVSS v3.1) / 7.1 (CVSS v4.0) (Medium/High depending on version)
- CWE: CWE-20 (Improper Input Validation)
## Affected Systems
- Products: SIMATIC CN 4100
- Versions: All versions prior to V4.0
- Configurations: Not explicitly detailed, but related to SFTP functionality.
## Vulnerability Description
The vulnerability lies in the application's handling of files within the SFTP folder. An attacker with low privileges (PR:L) can exploit this by storing arbitrary files in the SFTP folder, which can ultimately lead to a Denial of Service (DoS) condition on the device.
## Exploitation
- Status: Not explicitly stated as exploited in the wild.
- Complexity: Low (AC:L)
- Attack Vector: Network (AV:N)
## Impact
- Confidentiality: No impact (C:N)
- Integrity: No impact (I:N)
- Availability: High impact (A:H in CVSS v3.1 vector) due to Denial of Service.
## Remediation
### Patches
- Update to **Version V4.0 or later** for SIMATIC CN 4100.
- Reference link for update: hxxps://support.industry.siemens.com/cs/ww/en/view/109814144/
### Workarounds
- Follow the General Security Recommendations provided by Siemens.
- Protect network access to the devices using appropriate security mechanisms.
- Configure the environment according to Siemens' operational guidelines for Industrial Security.
## Detection
- Detection methods focus on monitoring atypical file uploads or management activity within the SFTP service directories of the SIMATIC CN 4100.
## References
- Vendor Advisory SSA-626991: hxxps://cert-portal.siemens.com/productcert/html/ssa-626991.html
- Siemens Operational Guidelines: hxxps://www.siemens.com/cert/operational-guidelines-industrial-security
- Siemens ProductCERT: hxxps://www.siemens.com/cert/advisories