Security Resilience

CVE-2023-43696

Sick Apu0200 Firmware ≤ 4.0.0.6

Published
09 October 2023
Modified
21 November 2024
Patch / advisory
CVSS Score v3.1 8.2
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N
EPSS Score 0.0088 58th percentile
Risk Priority 63 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-2023-43696 is a high-severity Improper Access Control (CWE-284) vulnerability in Sick Apu0200 Firmware. Its CVSS base score is 8.2 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Data Obfuscation (T1001); ranked in the top 42% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

Improper Access Control in SICK APU allows an unprivileged remote attacker to download as well as upload arbitrary files via anonymous access to the FTP server.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1001 Data Obfuscation Command And Control
Adversaries may obfuscate command and control traffic to make it more difficult to detect.
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.
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.
T1003.005 Cached Domain Credentials Credential Access
Adversaries may attempt to access cached domain credentials used to allow authentication to occur in the event a domain controller is unavailable.
T1007 System Service Discovery Discovery
Adversaries may try to gather information about registered local system services.
T1011.001 Exfiltration Over Bluetooth Exfiltration
Adversaries may attempt to exfiltrate data over Bluetooth rather than the command and control channel.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2025-5131Shared CWE-284, CWE-434
CVE-2025-3169Shared CWE-284, CWE-434
CVE-2025-11398Shared CWE-284, CWE-434
CVE-2026-16330Shared CWE-284, CWE-434
CVE-2025-8764Shared CWE-284, CWE-434
CVE-2026-3748Shared CWE-284, CWE-434
CVE-2025-13198Shared CWE-284, CWE-434
CVE-2025-15415Shared CWE-284, CWE-434
CVE-2026-5670Shared CWE-284, CWE-434
CVE-2025-7906Shared CWE-284, CWE-434

Affected Assets

sick
apu0200 firmware
≤ 4.0.0.6

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)
  • V5.1.1

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.

addresses: CWE-284 CWE-434

This control enforces ownership-based restrictions on portable storage device use, directly implementing access control over media insertion into organizational systems.

addresses: CWE-284 CWE-434

Hardware write-protect enforces access control on critical resources (e.g., firmware) independent of software state.

addresses: CWE-284

The access control policy and procedures directly mandate and enforce proper access control mechanisms across the organization.

addresses: CWE-284

Device lock enforces restricted access until re-authentication, directly reducing unauthorized use of active sessions.

addresses: CWE-284

Supervision and review of access control activities directly detects and remediates improper access configurations or usages.

addresses: CWE-284

Explicitly identifying and documenting actions permitted without identification or authentication enforces proper access control boundaries by defining justified exceptions.

addresses: CWE-284

By automatically labeling outputs with security attributes, the control supports attribute-based enforcement and reduces exploitability of improper access control weaknesses.

addresses: CWE-284

Associating and retaining security attributes with data directly supports enforcement of access control decisions across storage, processing, and transmission.

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.PS-01 partial match
blocks

Hardened configuration baselines can enforce allowed file types and processing rules.

PR.PS-05 partial match
blocks

Restricting execution of unauthorized software directly blocks dangerous uploaded files from running.

PR.PS-06 partial match
blocks

Secure development practices include input validation and file-type restrictions that prevent this weakness.

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.

blocks

A.5.1 only requires that an information security policy and topic-specific policies (including on access control) exist and are reviewed; it does not itself enforce, implement or act on any access restriction, so the weakness can still be exploited (per the owner's explicit rule that governance/dependency clauses score none on effect verbs).

removes
blocks

A.5.15 directly mandates determining requirements, defining/implementing topic-specific access control policy+rules (with explicit references to 8.3, 5.16, 5.18), and enforcing authorized access while preventing unauthorized access, which squarely stops exploitation of most CWE-284 instances; the bounded remainder is the physical slice (explicitly delegated to 7.2-7.4) plus any second-order defects like path traversal that are not authorization decisions.

blocks

A.5.16's identity lifecycle (unique binding, timely disable/remove, no duplicates, oversight of shared/non-human) directly stops most improper access by ensuring the actor in an access decision is correctly identified and authorized; the bounded remainder is non-identity mechanisms in CWE-284 such as path traversal or CSRF that do not turn on actor identity at all.

blocks

A.5.18 directly governs the provisioning, review, adjustment and timely revocation of both physical and logical access rights per business rules, segregation of duties and risk-evaluated changes/terminations; this stops most unauthorized-actor exploitation paths named by CWE-284, with a bounded remainder (e.g. path-traversal or CSRF cases that are not authorization decisions at all)

Hardening callouts derived

DISA STIG baselines are authored against specific weaknesses. Where this CVE cites a broad weakness class, the mapping is not asserted at that abstraction (owner ruling, 2026-09-25: grade only at Base and below), so no rule is shown here rather than a rule shown against the wrong grain.

  • No fine-grained STIG row for CWE-284, a pillar-level weakness. Rules are authored against its narrower children: CWE-749, CWE-1220.

References