Blumenthal and Rubio also wanted to know if Super Micro had worked with US law enforcement to address reports of tampering, what defenses it could mount (such as firmware updates or hardware configuration changes) and whether China had requested or restricted security info.

The politicians gave Super Micro until October 17th to provide its responses. We've asked Super Micro for comment.

The letter puts Super Micro in the hot seat, although it's not certain that much will result from the request. The company and those who supposedly used compromised servers, such as Amazon and Apple, have vehemently denied even some of the basic details of the Bloomberg story at the heart of the allegations. Super Micro isn't likely to change its tune, whether or not it's telling the truth. And when Homeland Security doesn't see a reason to pursue the matter, you might not see an investigation unless Super Micro reveals something truly eyebrow-raising. If there are any secrets, officials will likely need more than a letter to reveal them.

Update: Super Micro told Engaget in a statement that it had received the letter and was ready to engage with the senators. You can read the full response below.