The massive data breach could affect as many as 80 million customers.
The Senate passed a cybersecurity bill on Thursday to protect critical infrastructure.
Details mirror a previous Chinese cyberattack.
The advisory was sent to businesses in what is described as a "flash."
The commission's members are raising new alarms about cyberattacks.
“It is important to highlight that we really started this trend," Snowden said.
Apple fought back against newly discovered malware used to spy on Chinese iPhone users.
This year is expected to see 42.8 million cyberattacks, roughly 117,339 per day.
China is responsible for the most cyberattacks in the United States, Comey said.