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Siemens SICAM A8000 RTUs

Plan Patch8.1ICS-CERT ICSA-20-343-07Dec 8, 2020
Attack VectorNetwork
Auth RequiredNone
ComplexityLow
User InteractionRequired
Summary

SICAM A8000 RTU devices (CP-8000, CP-8021, CP-8022) use weak or deprecated cryptographic ciphers in their web-based management interface. An attacker could exploit this by downgrading the connection to a weak cipher and then intercepting or decrypting sensitive communications, including credentials or control commands. The vulnerability stems from improper validation of cipher strength during TLS/SSL negotiation (CWE-693).

What this means
What could happen
An attacker could intercept or decrypt sensitive communications to SICAM A8000 RTUs due to weak cipher configuration, potentially exposing control data or credentials used to manage critical substation equipment.
Who's at risk
Water utilities and electric utilities with Siemens SICAM A8000 remote terminal units (RTUs) should be concerned. These devices are commonly deployed at substations and pumping stations to monitor and control distribution equipment. Engineering staff and operators who access the RTU configuration interface over the network are the primary users at risk.
How it could be exploited
An attacker on the same network or positioned to intercept traffic could downgrade the encrypted connection to a weak cipher, then decrypt communications or perform a man-in-the-middle attack to capture credentials or inject commands into the RTU management interface.
Prerequisites
  • Network access to the RTU's management interface (typically port 443)
  • Ability to intercept or influence network traffic to the device
  • Weak ciphers must be enabled on the device (default configuration)
remotely exploitablelow complexityaffects safety-critical substation controlno authentication required to establish a connection (cipher downgrade)default weak ciphers likely enabled
Exploitability
Low exploit probability (EPSS 0.2%)
Affected products (3)
3 with fix
ProductAffected VersionsFix Status
SICAM A8000 CP-8000: All<V1616
SICAM A8000 CP-8021: All<V1616
SICAM A8000 CP-8022: All<V1616
Remediation & Mitigation
0/4
Do now
0/2
WORKAROUNDConfigure the RTU browser interface to accept only strong/secure ciphers (disable weak ciphers such as DES, RC4, MD5)
HARDENINGRestrict network access to the RTU management interface using firewall rules—allow only authorized engineering workstations and management systems
Schedule — requires maintenance window
0/1

Patching may require device reboot — plan for process interruption

HOTFIXUpdate SICAM A8000 CP-8000, CP-8021, and CP-8022 to firmware version 16 or later
Long-term hardening
0/1
HARDENINGImplement network segmentation to isolate the RTU and control system network from the business network and Internet
View full CISA ICS-CERT advisory
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