Security Resilience

CVE-2023-49621

Siemens Simatic Cn 4100 Firmware ≤ 2.7

Published
09 January 2024
Modified
16 December 2025
Patch / advisory
View advisory
CVSS Score v3.1 9.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0060 47th percentile
Risk Priority 72 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2023-49621 is a critical-severity Use of Default Credentials (CWE-1392) vulnerability in Siemens Simatic Cn 4100 Firmware. Its CVSS base score is 9.8 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Protocol or Service Impersonation (T1001.003); ranked at the 47th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to CM-6 (Configuration Settings) and IA-5 (Authenticator Management) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

A07:2025 Authentication Failures

EU & UK References

Vulnerability Data

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…

more

affected device.

CWE(s)
CWE-1392

Related Threats

MITRE ATT&CK Enterprise Techniques

T1001.003 Protocol or Service Impersonation Command And Control
Adversaries may impersonate legitimate protocols or web service traffic to disguise command and control activity and thwart analysis efforts.
attack.mitre.org →
T1003.001 LSASS Memory Credential Access
Adversaries may attempt to access credential material stored in the process memory of the Local Security Authority Subsystem Service (LSASS).
attack.mitre.org →
T1003.004 LSA Secrets Credential Access
Adversaries with SYSTEM access to a host may attempt to access Local Security Authority (LSA) secrets, which can contain a variety of different credential materials, such as credentials for service accounts.
attack.mitre.org →
T1003.007 Proc Filesystem Credential Access
Adversaries may gather credentials from the proc filesystem or `/proc`.
attack.mitre.org →
T1007 System Service Discovery Discovery
Adversaries may try to gather information about registered local system services.
attack.mitre.org →
T1011.001 Exfiltration Over Bluetooth Exfiltration
Adversaries may attempt to exfiltrate data over Bluetooth rather than the command and control channel.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-22925Same product: Siemens Simatic Cn 4100
CVE-2024-32742Same product: Siemens Simatic Cn 4100
CVE-2025-40938Same product: Siemens Simatic Cn 4100
CVE-2024-32740Same product: Siemens Simatic Cn 4100
CVE-2023-49251Same product: Siemens Simatic Cn 4100
CVE-2024-32741Same product: Siemens Simatic Cn 4100
CVE-2026-22924Same product: Siemens Simatic Cn 4100
CVE-2023-49252Same product: Siemens Simatic Cn 4100
CVE-2025-40593Same product: Siemens Simatic Cn 4100
CVE-2025-40939Same product: Siemens Simatic Cn 4100

Affected Assets

siemens
simatic cn 4100 firmware
≤ 2.7

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)

—

Validate
Prove the fix (OWASP ASVS)
  • V13.2.1

Mitigating Controls (NIST 800-53 r5) AI

CM-6 Configuration Settings good match

Secure configuration settings establish baselines that prohibit default credentials on system components.

IA-5 Authenticator Management good match

Authenticator management requires verification of identity and secure distribution of initial authenticators, directly stopping default credentials from being left in place.

RA-5 Vulnerability Monitoring and Scanning good match

Vulnerability scanning can discover default credentials after deployment but does not stop their introduction.

AC-2 Account Management partial match

Account management processes include assignment and control of initial account credentials, reducing the chance defaults remain active.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.AA-01 partial match
blocks

Credential management processes directly require replacing or disabling default passwords and keys.

PR.AA-03 partial match
blocks

Authentication policies can enforce non-default credential strength but do not explicitly address initial deployment defaults.

PR.PS-01 partial match
blocks

Hardened baselines and configuration management explicitly prohibit default credentials on deployed systems.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.26 Application security requirements partial match
removes
A.8.28 Secure coding partial match
removes
A.8.9 Configuration management partial match
blocks

The requirement to replace vendor default authentication information immediately after installation directly counters the use of default credentials that attackers commonly target.

References