Denial of Service Vulnerability in CP 44x-1 RNA before V1.5.18
Plan Patch7.4SSA-480937May 10, 2022
Attack VectorAdjacent
Auth RequiredNone
ComplexityLow
User InteractionNone needed
Summary
Denial of service vulnerability in Siemens SIMATIC CP 442-1 RNA and CP 443-1 RNA communication processor modules before version 1.5.18. The vulnerability allows an unauthenticated attacker on the automation network to send specially crafted messages that cause the communication processor to stop responding, disrupting SCADA and field device communications. The issue is addressed in firmware version 1.5.18 and later.
What this means
What could happen
An attacker with access to the automation network could send specially crafted messages to the CP 44x-1 RNA communication processor, causing it to become unresponsive and interrupting communication between the PLC and field devices until the module is restarted.
Who's at risk
Siemens SIMATIC automation systems using CP 442-1 RNA or CP 443-1 RNA communication processor modules. These are critical components in PLC networks that handle communication between the main controller and remote I/O modules, variable frequency drives, operator interfaces, and SCADA systems in water treatment, power distribution, and manufacturing facilities.
How it could be exploited
An attacker with network access to the CP 44x-1 RNA communication processor sends a malformed network message designed to trigger a resource exhaustion condition, causing the module to stop processing legitimate traffic. This could disrupt SCADA communications, process monitoring, and remote control capabilities.
Prerequisites
- Network access to the CP 44x-1 RNA communication processor on the automation network
- No authentication required to send malformed messages
remotely exploitableno authentication requiredlow complexityaffects industrial automation communicationshigh availability impact
Exploitability
Low exploit probability (EPSS 0.3%)
Affected products (2)
2 with fix
ProductAffected VersionsFix Status
SIMATIC CP 442-1 RNA< V1.5.181.5.18
SIMATIC CP 443-1 RNA< V1.5.181.5.18
Remediation & Mitigation
0/1
Schedule — requires maintenance window
0/1Patching may require device reboot — plan for process interruption
HOTFIXUpdate CP 442-1 RNA and CP 443-1 RNA modules to firmware version 1.5.18 or later
CVEs (1)
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