CVE intelligence and bounded remediation

CVE-2020-28397 — Siemens Cpu 1504D Tf Firmware security vulnerability

Medium CVSS 5.3

A vulnerability has been identified in SIMATIC Drive Controller family (All versions < V2.9.2), SIMATIC ET 200SP Open Controller CPU 1515SP PC2 (incl. SIPLUS variants) (All versions < V21.9), SIMATIC S7 PLCSIM Advanced (All versions > V2 < V4), SIMATIC S7-1200 CPU family (incl. SIPLUS variants) (Version V4.4), SIMATIC S7-1500 CPU family (incl. related ET200 CPUs and SIPLUS variants) (All versions > V2.5 < V2.9.2), SIMATIC S7-1500 Software Controller (All versions > V2.5 < V21.9), TIM 1531 IRC (incl. SIPLUS NET variants) (Version V2.1). Due to an incorrect authorization check in the affected component, an attacker could extract information about access protected PLC program variables over port 102/tcp from an affected device when reading multiple attributes at once.

Severity
Medium
CVSS
5.3 (3.1)
Published
2021-08-10
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-863

Affected products

  • siemens / cpu_1504d_tf_firmware
  • siemens / cpu_1507d_tf_firmware
  • siemens / cpu_1515sp_pc2_tf_firmware
  • siemens / simatic_s7_plcsim_advanced_firmware
  • siemens / simatic_s7-1500_software_controller
  • siemens / tim_1531_irc_firmware / 2.1

Showing 6 representative product identities from 60 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

Matched remediation archetype

Authorization bypass, IDOR, and cross-tenant access

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Check exposure

  • Map object and action authorization checks across API, UI, batch, import/export, and background-job paths.
  • Identify tenant, ownership, role, and policy boundaries for affected resources and administrative operations.
  • Use synthetic fixtures to compare intended access matrices without accessing another user's real data.

Remediate safely

  • Enforce server-side authorization at each resource access and state transition using the authenticated principal and trusted tenant context.
  • Scope data queries by tenant and ownership; treat client-supplied identifiers, roles, and policy claims as untrusted.
  • Add deny-by-default policy tests for horizontal and vertical access across every affected transport.

Authoritative sources

Complete CVE record and remediation plan

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