Chinese cyber group uses new malware to maintain access to hacked networks

The Chinese espionage group UNC5221, also known as VerdantBamboo, used the Brickstorm backdoor and previously undocumented malware named Plenet and AgentPSD to access Microsoft 365 environments. Investigators found that the attackers had remained in the victim’s network for at least 18 months and had also compromised the victim’s managed service provider.