CVE-2021-37186 Weak cryptography in LOGO! CMR2020
Weak random number generation in TCP/IP stack allows adjacent attackers to spoof connections and access sensitive information on Siemens industrial devices.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2021-37186?
CVE-2021-37186 is a medium-severity vulnerability in Siemens LOGO! CMR2020, published on 14 Sep 2021. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
A vulnerability has been identified in LOGO! CMR2020 (All versions < V2.2), LOGO! CMR2040 (All versions < V2.2), SIMATIC RTU3010C (All versions < V4.0.9), SIMATIC RTU3030C (All versions < V4.0.9), SIMATIC RTU3031C (All versions < V4.0.9), SIMATIC RTU3041C (All versions < V4.0.9). The underlying TCP/IP stack does not properly calculate the random numbers used as ISN (Initial Sequence Numbers). An adjacent attacker with network access to the LAN interface could interfere with traffic, spoof the connection and gain access to sensitive information.
Weakness: CWE-330
Which versions are affected by CVE-2021-37186?
It affects 6 products.
Products include Siemens Logo\! Cmr2020 Firmware, Siemens Logo\! Cmr2040 Firmware, Siemens Simatic Rtu3010c Firmware, Siemens Simatic Rtu3030c Firmware, Siemens Simatic Rtu3031c Firmware, Siemens Simatic Rtu3041c Firmware.
How do I fix CVE-2021-37186?
No fix has been published for CVE-2021-37186 yet. Limit exposure of the affected software until one is available.
Is CVE-2021-37186 being exploited?
There is no known exploitation of CVE-2021-37186 in the wild and no public exploit code.
Sources
Also known as GHSA-5g5j-x767-23r3.