A remote code execution vulnerability in the WebAdmin of SG UTM was discovered and responsibly disclosed to Sophos in 2020. It was reported via the Sophos bug bounty program by an external security researcher. The vulnerability was fixed in September 2020.
Devices that have not been updated in the last year and still have WebAdmin exposed to the WAN are vulnerable. Check this Knowledge Base Article for additional information to determine if a device has been compromised and how to remediate.
Customers can protect themselves by ensuring their WebAdmin is not exposed to WAN.
This can be achieved by keeping Internal (LAN) (Network) or another internal-only network definition as the sole entry in Management→WebAdmin Settings→WebAdmin Access Configuration→Allowed Networks.
Internal (LAN) (Network)