This indicates an attack attempt to exploit a Command Execution vulnerability in multiple Grandstream devices.
The vulnerability is caused by an error when the vulnerable software handles a malicious HTTP request. A remote attacker may be able to exploit this to execute arbitrary code on vulnerable systems.
Grandstream GAC2500 188.8.131.52
Grandstream GXP2200 184.108.40.206
Grandstream GVC3202 220.127.116.11
Grandstream GXV3275 before 18.104.22.168 Beta
Grandstream GXV3240 before 22.214.171.124 Beta
System Compromise: Remote attackers can gain control of vulnerable system.
Apply the most recent upgrade or patch from the vendor.