Hello  sugu,
As you are asking about ISDF so i think its a(information security digital forensic) so.Digital forensics is a key component in Cyber Security. Many people hear the term forensics, or computer forensics, or digital forensics and instantly think, thats just for law enforcement, but the truth is, digital forensics has a key place on every cyber security team. In fact, without it, chances are your organizations Security posture and maturity will fail to see its full potential

Computer hacking forensic investigation is the process of detecting hacking attacks and properly extracting evidence to report the crime and conduct audits to prevent future attacks
I hope you get it
Best of luck for your future