Security Resilience

CVE-2023-33921

Siemens Cpci85 Firmware ≤ v05

Public PoC
Published
13 June 2023
Modified
21 November 2024
Patch / advisory
View advisory
CVSS Score v3.1 6.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0039 32th percentile
Risk Priority 50 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-2023-33921 is a medium-severity Exposed Dangerous Method or Function (CWE-749) vulnerability in Siemens Cpci85 Firmware. Its CVSS base score is 6.8 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Junk Data (T1001.001); ranked at the 32th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

OWASP Top 10 for Web (2025)

A01:2025 Broken Access Control

EU & UK References

Vulnerability Data

A vulnerability has been identified in CP-8031 MASTER MODULE (All versions < CPCI85 V05), CP-8050 MASTER MODULE (All versions < CPCI85 V05). The affected devices contain an exposed UART console login interface. An attacker with direct physical access could try…

more

to bruteforce or crack the root password to login to the device.

CWE(s)
CWE-749NVD-CWE-Other

Related Threats

MITRE ATT&CK Enterprise Techniques

T1001.001 Junk Data Command And Control
Adversaries may add junk data to protocols used for command and control to make detection more difficult.
attack.mitre.org →
T1003.007 Proc Filesystem Credential Access
Adversaries may gather credentials from the proc filesystem or `/proc`.
attack.mitre.org →
T1010 Application Window Discovery Discovery
Adversaries may attempt to get a listing of open application windows.
attack.mitre.org →
T1016.002 Wi-Fi Discovery Discovery
Adversaries may search for information about Wi-Fi networks, such as network names and passwords, on compromised systems.
attack.mitre.org →
T1025 Data from Removable Media Collection
Adversaries may search connected removable media on computers they have compromised to find files of interest.
attack.mitre.org →
T1027.002 Software Packing Stealth
Adversaries may perform software packing or virtual machine software protection to conceal their code.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2023-33920Same product: Siemens Cp-8031 Master Module
CVE-2023-33919Same product: Siemens Cp-8031 Master Module
CVE-2024-35209Same vendor: Siemens
CVE-2024-24924Same vendor: Siemens
CVE-2024-36266Same vendor: Siemens
CVE-2023-44321Same vendor: Siemens
CVE-2024-29119Same vendor: Siemens
CVE-2023-24581Same vendor: Siemens
CVE-2024-39569Same vendor: Siemens
CVE-2025-40830Same vendor: Siemens

Affected Assets

siemens
cpci85 firmware
≤ v05 · ≤ v05

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)
  • 4 hardening rules · 2 OS baselines
Validate
Prove the fix (OWASP ASVS)
  • V8.2.1

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

CM-7 Least Functionality
addresses: CWE-749

Explicitly prohibiting dangerous or unnecessary functions and services prevents exposure of methods that could be directly exploited.

SC-25 Thin Nodes
addresses: CWE-749

Minimal functionality removes or avoids exposure of dangerous methods and functions.

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.

ID.RA-01 partial match
blocks

Vulnerability identification processes will surface exposed dangerous methods during assessment.

PR.AA-05 partial match
blocks

Enforcing least-privilege authorization directly prevents unrestricted dangerous API methods.

PR.IR-01 partial match
blocks

Logical access controls at the network/environment layer can limit reachability of exposed functions.

PR.PS-06 partial match
blocks

Secure SDLC practices stop developers from exposing dangerous functions in the first place.

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.5.14 Information transfer partial match
removes
A.5.15 Access control partial match
removes
A.5.16 Identity management partial match
removes
A.5.17 Authentication information partial match
removes
A.5.18 Access rights partial match
removes
A.8.10 Information deletion partial match
removes

Hardening callouts derived

Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (higher-evidence rows only; rows rated `none` are excluded).

Ubuntu 22.04 (3 rules)
  • V-260559 Ubuntu 22.04 LTS must ensure only users who need access to security functions are part of sudo group. blocks CWE-749
  • V-260529 Ubuntu 22.04 LTS must be configured so that remote X connections are disabled, unless to fulfill documented and validated mission requirements. blocks CWE-749
  • V-260557 Ubuntu 22.04 LTS must be configured to use AppArmor. blocks CWE-749
Ubuntu 24.04 (1 rule)
  • V-270748 Ubuntu 24.04 LTS must ensure only users who need access to security functions are part of sudo group. blocks CWE-749

References