Since Advanced Persistent Threats (APTs) are the most sophisticated form of cyber weapon to date, previous research has indicated that further knowledge about the actors and their Modus Operandi (MO) is needed as the groups are highly organized, skilled and motivated when engaging in cyberoperations with different aims. This thesis poses the research question: how does the desired impact of an APT affect its MO? To answer the research question, a cross-case study is performed using a qualitative case study design. The method of structured focused comparison is employed where the cases of the Russian attributed APT the Sandworm Team and the North Korean-linked APT the Lazarus Group which have engaged in numerous cyberoperations with multiple impacts are compared against the Russian attributed APT Turla and the North Korean attributed APT Kimsuky which have performed numerous cyberoperations with a single impact. The findings, using the MITRE ATT&CK framework, show that there are similarities across the cases in terms of the techniques used but differences in terms of malwares used. The findings therefore indicate that the malware may be the key determinant of the impact of a cyberoperation by an APT.