T 4.83 Malfunctions of self-developed macros in Outlook

For reasons of interoperability, many software manufacturers equip their tools and applications with programming interfaces, e.g. as Application Programming Interface (API). These allow for also using certain functions from other programs or for extending the scope of functions of the application. In this way, errors and incorrect calculations in macros may constitute an increased risk. As a deliberate act, self-developed software with a harmful function could also be used for attacks (see T 5.164 Misuse of programming interfaces in Outlook).

For Microsoft Outlook, programming interfaces are offered which the users can use to write their own applications or functional extensions (macros) that can send and receive messages, appointments, and tasks using the client.

Example:

• A macro is used to collect certain keywords in emails for a statistic. The macro counts incorrectly due to an index error. This triggers incorrect economic decisions such as purchasing or selling activities.