Legacy systems are IT systems that have been in use for several years or even decades and are still being used despite being technologically outdated. These systems may consist of hardware and software components that have not been further developed or updated for many years.

One main problem with legacy systems is that they often no longer meet the requirements and standards of modern IT systems. For example, they may have weaknesses in terms of security that are no longer sufficient for current threats. These vulnerabilities can be exploited by hackers to steal confidential information or disable the system.