The provided sources collectively offer a comprehensive examination of cyber espionage, defining it as the unauthorized acquisition of sensitive information for strategic advantage. They discuss the diverse actors involved, from nation-states to insiders, alongside their motivations like economic gain or national security. The text details various attack methodologies, including sophisticated social engineering, advanced malware like RATs, and the pervasive threat of supply chain compromises, often mapped using the MITRE ATT&CK framework. Furthermore, the sources explore the far-reaching impacts of such activities, ranging from significant economic losses and national security risks to the erosion of public and international trust. Finally, the collection outlines comprehensive countermeasures, encompassing technical defenses such as network and endpoint security, data-centric strategies, the role of cyber threat intelligence, and organizational frameworks like NIST CSF and ISO 27001, while also looking towards emerging threats like AI-driven attacks and quantum computing's implications for encryption.

Research done with the help of artificial intelligence, and presented by two AI-generated hosts.