Why You Shouldn’t Share Links via Facebook Messenger
In a post on Medium, security researcher Inti De Ceukelaire explains how any developer could see the URLs you share in private Facebook messages. Even if you’re only linking to cat pictures, URLs sometimes contain sensitive information that you’re unaware of, such as names, locations, and even hidden keys. When De Ceukelaire reached out to Facebook, the company said that this was “publicly documented and intentional behavior.” Long story short: be cautious about using Facebook Messenger, particularly for any sensitive communications!
Why would you put anything online that you wouldn't want to see on the front page of a newspaper?
From what I could understand, in Messenger there is more information obtained through the link than the original share and can include personal info. Exactly how and the risk level is what I could not figure out because it became too technical.
The problem is that people believe (and Facebook encourages them to believe) that one-on-one conversations in Facebook Messenger are private. That's clearly not true, at least when it comes to links.
So, can I share the URL of this page on FB (not Messenger)?
(To be honest, I could not understand the actual article.)
You can, but the point is that it's possible for someone to discover that link. In the case of this page, there's no confidential information included in the link, but the possibility of a link transferred via Facebook Messenger getting out could be a concern if we were instead talking about a link to a Google Doc that contained sensitive data.