Recently, a hot topic in the news is the accusation by China's National Security Agency that the United States breached China's National Time Service Center. I have read several news articles that generally introduce this event, but none mention the detailed process. Later, I found a detailed analysis in an official tweet by the National Computer Network Emergency Response Technical Team/Coordination Center (CNCERT), titled "Technical Analysis Report on the Cyber Attack by the U.S. National Security Agency on the National Time Service Center". The content is very professional and provides detailed data, so experts can refer to this article.
I skimmed through it and found that although the introduction is detailed, the initial step of obtaining login credentials for the computer terminals is only briefly mentioned. How did the NSA obtain the login permissions for the computers at the Time Service Center? How was the first breach in the security defense opened?
Triangulation
According to the disclosure by CNCERT, the initial breach occurred between March 24, 2022, and April 11, 2023, when the NSA attacked and stole secrets from more than 10 devices at the Time Service Center through "Triangulation". In September 2022, the attacker obtained the login credentials for an office computer through a foreign-brand mobile phone used by a network administrator at the Time Service Center, and used these credentials to gain remote control of the office computer.
No further information was provided, so I searched for this Triangulation. This is not the triangulation in surveying, but rather a term first disclosed by the renowned Russian security firm Kaspersky. The original article is Operation Triangulation: The last (hardware) mystery. The core attack chain is shown in the figure below:

