Identify the phase of SDLC this case fall in either requirements and system design or system implementation,deployment and maintenance. And what can be the mitigation strategies of the case, what could have been done differently to avoid the incidents and liabilities that occurred

Case Study 9: A system administrator, fearing the company's layoff, embedded malicious code within scripts on the organization's servers. The code was set to execute on his next birthday, approximately six months in the future. Had he been successful, the code would have wiped out critical data on more than 70 servers and caused widespread financial damage. It also would have caused potential health risks to the organization's customers. Even after surviving the layoffs a few days later, the insider did not remove the malicious code; in fact, he modified it one month later. The malicious code contained a programming error and failed to execute on his birthday as scheduled. However, the insider allegedly corrected the programming error six months later, setting the code to execute on his next birthday. Fortunately, a few months before the intended execution date, another system administrator investigating a system error discovered the malicious code and disabled it