Cisco Webex windows application read my outlook calendar without any authorization

Question

I received a webex invitation, I downloaded the windows client and installed it.

I was surprised to see that webex was able to read all my outlook calendar entries without any authentication or authorization. I could not find in the internet any reasonable explanation.

Can anyone explain? or Should I report this as a security bug?

Answer 1

If there are any tutorials on Outlook Calendars, I have not found them. Almost, everything I know is the result of experimentation. My first investigation was to see if I could read all the items in my calendar and decode them. Single appointments have a simple format and were easy. Recurring items were more complicated because of how many options there are. You also need to appreciate that if you create an entry for a weekly meeting with exceptions for the weeks you are away or the occasions the meeting is changed to a different date or time, you are creating one entry for the regular situation plus one sub-entry per exception. So, if you want to know if you have a meeting on day X, you must check the date of every single appointment and calculate the dates of every recurring appointment and its exceptions.

I do not remember why I was interested in calendars; perhaps it was idle curiosity. I am retired and this is my hobby.

The first Excel VBA macro I wrote, output each calendar entry in a tidy format so I could prove to myself I knew where everything was. I don't think that macro deals with exceptions. It seemed to work when I tested it a few weeks ago, so I posted it in response to a question.

The second Excel macro I wrote, calculated all the appointments that occurred within a given period. When I tested that recently, I thought there was a bug but, on closer investigation, I found I had not finished it. I decided to finish that macro and add categories which were of interest to the OP. I also posted that macro.

The first macro is in https://stackoverflow.com/a/60363647/973283 . The second macro is in a second answer to the same question.

These are Excel VBA macros. Do you read VBA well enough to extract the information you need from these macros? If not, perhaps I should document calendar items. I spent a lot of time investigating calendars, as a public service, I should make the results of my investigation available to others.

I should qualify: "Almost, everything I know is the result of experimentation". Microsoft provides dictionary style entries for all the properties of a calendar item. But how helpful is knowing there are four types of calendar item if you do not know what properties are used for each type.