Microsoft today shared details on how the SolarWinds hackers were able to remain undetected by hiding their malicious activity inside the networks of breached companies. Previously unknown information was disclosed by security experts part of the Microsoft 365 Threat Intelligence Center (MSTIC), and Microsoft Cyber Defense Operations Center (CDOC) Microsoft also provided a list of the most fascinating and unusual tactics, techniques, and procedures (TTPs) used in these attacks. The FBI, CISA, ODNI, and NSA earlier this month says that it is likely a Russian-backed Advanced Persistent Threat (APT) group.
Source: https://www.bleepingcomputer.com/news/security/microsoft-shares-how-solarwinds-hackers-evaded-detection/