Based on the context, - CAB is likely to be the acronym for "Change Advisory Board", a group of people who need to approve changes for IT. - ECAB would then stand for "Emergency Change Advisory Board", a term coined at least as part of ITIL ( Information Technology Infrastructure Library). VGIC could be a shorthand for the client or other authority (as it seems you cannot establish the ECAB without their approval), but I can't guess from this context. Working in IT, it's sometimes frustrating to read documentation filled with acronyms, especially if it's lacking the abbreviations table at the beginning of the document. I feel your pain.

Whoever wrote those acronyms is using it to ensure that communication does NOT occur. As a native I have no idea what each means, though IT can be "Information Technology". The person who wrote the document should be removed from the company. This sort of "jargonism" is used when people fear for their jobs and making life harder for people to enter the "inner circle" is part of that process. Good luck