Vulnerability giving attackers full control of Macs is under active exploitation

How are people running their Macs exposed directly to the Internet?

In order to make this work, a user would have to:

1. Turn on screen sharing
2. Turn off the OS firewall block
3. Set up NAT routing on their router to forward port 5900 to their Mac

Seems to me that anyone who could do this would know it was a really bad idea?

Especially since you can already tunnel screen sharing via Apple ID or FaceTime to connect without leaving the port open.

One of the ways it can happen is if a router doesn’t have a proper IPv6 firewall.

The majority of internet users in the USA have IPv6 connectivity - something like 55-60% overall, and close to 100% on some networks. T-Mobile’s network is 100% IPv6-only, using 464XLAT for connectivity to legacy IPv4-only servers. Most Comcast customers have IPv6 too, as they were the first major ISP to roll out IPv6, close to 15 years ago now.

Without an IPv6 firewall on the router, all devices on your network are directly accessible from the outside world (unless they’re running their own firewall, of course). At least Windows ships with a firewall enabled by default, which reduces the impact for Windows users.

I’ve seen this in places you wouldn’t expect it, too. TP-Link’s prosumer/SMB 10Gbps router (Omada ER8411) didn’t have an IPv6 firewall until about a year after launch. I had to disable IPv6 until then. They did add it, but I’ve since switched to a Unifi Cloud Gateway Fiber.

Thankfully I haven’t seen it recently, so maybe it’s not an issue any more on modern hardware.

NAT is a hack, not a security feature, and IPv6 removes the need for it. The firewall is the security feature. (edit: the firewall on the router)

The firewall is the security feature.

Mmm whole new class of bugs and vulns being introduced in one statement.

Now my 3d printer needs its firewall babysat. So does my smart fan. Excellent idea.

Homes and businesses should be islands.