It's possible. There have been some viruses with effective digital signature authentication before. As for how they got it, there is no way to know. It may be leaked or used by insiders, but they are all small probability events. However, if the landlord uses Comodo's HIPS function, it is still recommended not to use digital signature for the white list. If the rules are not strict enough, some white+black samples may bypass the rules.
If the landlord still wants to use the white list, it is recommended to cooperate with Tencent computer housekeeper. Computer housekeeper has a high killing ability, and active defense is also making efforts in the near future. The white+black sample has improved the defense, and the hip with Comodo should be able to improve the defense ability better.
Welcome to consult the computer housekeeper enterprise platform for other questions!