Multiple vulnerabilities were reported in the Nucleus Real-Time Operating System (RTOS). The Nucleus RTOS is an essential component in several WAGO PLCs and fieldbus coupler. WAGO uses older Versions of the Nucleus RTOS also in legacy products. For additional information please consult the official Siemens advisory: • Advisory SSA-044112
The reported vulnerabilities allow an attacker who has access to the device and is able to exploit the vulnerabilities, to manipulate and disrupt the device. Please consult the CVE entries listed above for more details. WAGO devices are not affected by CVE-2021-31885. Vulnerable to all vulnerabilities listed above: 750-829, 750-831/000-00x, 750-852, 750-880/0xx-xxx, 750-881, 750-882, 750-885/0xx-xxx, 750-889, 750-331, 750-352/xxx-xxx Vulnerable only to CVE-2021-31344, CVE-2021-31346, CVE-2021-31890: 750-823, 750-832/000-00x, 750-862, 750-890/0xx-xxx, 750-891, 750-893, 750-332, 750-362/xxx-xxx, 750-363/xxx-xxx, 750-364/xxx-xxx, 750-365/xxx-xxx
The DHCP client application assumes that the data supplied with the 'Hostname' DHCP option is NULL terminated. In cases when global hostname variable is not defined, this may lead to Out-ofbound reads, writes, and Denial-of-service conditions.
A vulnerability has been identified in APOGEE MBC (PPC) (BACnet) (All versions), APOGEE MBC (PPC) (P2 Ethernet) (All versions), APOGEE MEC (PPC) (BACnet) (All versions), APOGEE MEC (PPC) (P2 Ethernet) (All versions), APOGEE PXC Compact (BACnet) (All versions = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and = V2.3 and < V6.30.016), Nucleus NET (All versions), Nucleus ReadyStart V3 (All versions < V2017.02.4), Nucleus ReadyStart V4 (All versions < V4.1.1), Nucleus Source Code (All versions), PLUSCONTROL 1st Gen (All versions), SIMOTICS CONNECT 400 (All versions < V0.5.0.0), TALON TC Compact (BACnet) (All versions < V3.5.4), TALON TC Modular (BACnet) (All versions < V3.5.4). ICMP echo packets with fake IP options allow sending ICMP echo messages to arbitrary hosts on the network. (FSMD-2021-0004)
Use general security best practices to protect systems from local and network attacks.
Do not allow direct access to the device from untrusted networks.
Update to the latest firmware according to the table in chapter solutions.
Disable the DHCP, DNS and the FTP port 21.
Industrial control systems (ICS) should not be directly accessible from the Internet, but should be protected by consistently applying the defense-in-depth strategy. The BSI provides general information on securing ICS in the ICS Compendium [BSI2013] and on the official BSI website [BSI2021].
For fieldbus coupler:
The listed fieldbus coupler and PLCs above are based on Nucleus V1 RTOS. At the moment there are no updates for this version available. Due to this reason WAGO recommends according to the recommendations of the BSI to implement the following measures:
Enforce segmentation controls and proper network hygiene to reduce the risk of vulnerable devices. Restrict external communication paths and isolate vulnerable devices in zones as a mitigating measure.
Ensure DHCP responses from non-authorized servers are blocked or discarded.
Monitor network traffic for anomalies and discard invalid packets.
Disable or block FTP, DHCP, DNS especially on critical network segments
Please check regularly for an update of this Advisory.
For fieldbus coupler:
We recommend all effected users to update to the firmware version listed below:
WAGO GmbH & Co. KG thanks the following parties for their efforts:
CERT@VDE for coordination (see )
Yuval Halaban, Uriel Malin, Tal Zohar from Medigate for reporting
Daniel dos Santos, Amine Amri, Stanislav Dashevskyi from Forescout Technologies for reporting
The full story
This article is one source in a clustered incident — the cluster page carries the summary, timeline and every other outlet covering it.
