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Denial of Service Vulnerabilities in SIMATIC S7-1200 CPU Family Before V4.7

Plan Patch7.5SSA-224824Feb 11, 2025
Attack VectorNetwork
Auth RequiredNone
ComplexityLow
User InteractionNone needed
Summary

SIMATIC S7-1200 CPU family before firmware version 4.7 contains two denial of service vulnerabilities that can be triggered by sending specially crafted network packets. An unauthenticated remote attacker can cause the affected PLCs to become unresponsive, disrupting automation and process control. The vulnerabilities are identified as CWE-404 and CWE-1286 and affect all S7-1200 CPU models including standard and SIPLUS variants across multiple configurations (AC/DC/Rly, DC/DC/DC, DC/DC/Rly).

What this means
What could happen
An attacker could send specially crafted network packets to cause the S7-1200 PLC to stop responding, halting automation logic and preventing normal process operation until the device is rebooted.
Who's at risk
This affects any organization using SIMATIC S7-1200 PLCs in automation systems, including water treatment plants, pumping stations, electrical substations, traffic control systems, and manufacturing facilities. All S7-1200 CPU variants (1211C, 1212C, 1212FC, 1214C, 1214FC, 1215C, 1215FC, 1217C, and SIPLUS variants) running firmware below V4.7 are at risk.
How it could be exploited
An attacker with network access to the S7-1200 CPU can send malformed packets to trigger a denial of service condition. The attack requires no credentials or authentication, and the CPU will become unresponsive to legitimate commands and process inputs.
Prerequisites
  • Network access to the S7-1200 CPU (port 102 for S7 communication or relevant industrial protocol ports)
  • No authentication required
Remotely exploitableNo authentication requiredLow complexity attackAffects critical process automationWide range of S7-1200 variants impactedHigh CVSS score (7.5)
Exploitability
Low exploit probability (EPSS 0.1%)
Affected products (34)
34 with fix
ProductAffected VersionsFix Status
SIMATIC S7-1200 CPU 1211C AC/DC/Rly< V4.74.7
SIMATIC S7-1200 CPU 1211C DC/DC/DC< V4.74.7
SIMATIC S7-1200 CPU 1211C DC/DC/Rly< V4.74.7
SIMATIC S7-1200 CPU 1212C AC/DC/Rly< V4.74.7
SIMATIC S7-1200 CPU 1212C DC/DC/DC< V4.74.7
Remediation & Mitigation
0/1
Schedule — requires maintenance window
0/1

Patching may require device reboot — plan for process interruption

HOTFIXUpdate SIMATIC S7-1200 CPU firmware to version 4.7 or later
View full Siemens ProductCERT advisory
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