Can malware jump between Macs on the same network?

[123123123]

I'm not certain which forum this fits best, so if it's better elsewhere, I'd appreciate it if the mods could move it.

Let's say that a Mac gets some form of malware – uncommon, I know, but not impossible. Is it possible that it could "jump" to other Macs on the same network, or even other nearby ones (via Bluetooth)? Assuming separate iCloud accounts.

 

[Mr_Brightside_@]

No

 

[mystery hill]

Yes, Malware can spread to devices on the same network.

AirPlay Security Flaws Impact Third-Party Devices and Unpatched Apple Products

Researchers at cybersecurity firm Oligo today outlined a series of AirPlay vulnerabilities that impact millions of Apple devices (via Wired) and...

www.macrumors.com

 

[123123123]

Yes, Malware can spread to devices on the same network.

AirPlay Security Flaws Impact Third-Party Devices and Unpatched Apple Products

Researchers at cybersecurity firm Oligo today outlined a series of AirPlay vulnerabilities that impact millions of Apple devices (via Wired) and...

www.macrumors.com

So what precautions should one take other than staying up to date on updates? If I want to take my MacBook to the local coffee shop and use their wifi, am I taking a serious risk?

 

[Brian33]

Could malware be written to spread to other Macs on a network? Sure! But I don't think it's a common feature.

If I want to take my MacBook to the local coffee shop and use their wifi, am I taking a serious risk?

IMHO, the risk of getting malware this way is probably low -- not non-existent, but low. If it were me, I'd turn off all Sharing features on my Mac (like File Sharing, Remote Login, etc), and maybe limit my time on the network, but I personally wouldn't worry a lot about other people's Macs infecting mine.

Rogue access points and man-in-the-middle attacks seem to be mentioned more often as a risk when on a public network.

 

[123123123]

Could malware be written to spread to other Macs on a network? Sure! But I don't think it's a common feature.


IMHO, the risk of getting malware this way is probably low -- not non-existent, but low. If it were me, I'd turn off all Sharing features on my Mac (like File Sharing, Remote Login, etc), and maybe limit my time on the network, but I personally wouldn't worry a lot about other people's Macs infecting mine.

Rouge access points and man-in-the-middle attacks seem to be mentioned more often as a risk when on a public network.

What about non-Mac devices on the network, like iPhones and iPads? I realize cross-platform malware is mostly nonexistent, but can they act as "vectors"?

 

[TheMountainLife]

So what precautions should one take other than staying up to date on updates? If I want to take my MacBook to the local coffee shop and use their wifi, am I taking a serious risk?

I'll provide some intermediate advice as I used to install wifi access points for small business from medical to restaurants.

- Use your own hotspot over public wifi. If you must use public wifi use a VPN.
- Change the name of your Mac. I've always found it annoying that Apple names your device based off the Apple ID/User account or whatever so change it to something obscure vs "Charlie's MacBook Air" as this can be seen from the wifi owner and anyone that scans the network if they aren't properly segmented.
- Ensure Limit IP address tracking is enabled and that Private Wi-Fi address is set to rotating in system preferences.
- Manually assign your own DNS preferences instead of whatever is automatically pushed from connection. (Cloudflare, AdGuard, Google are all fine)
- Under Sharing in System Preferences ensure screen sharing, remote management, remote login and file sharing are unchecked unless there is an absolute need. If so, it should only be set to users with a strong password, not all users.

That's all I can recall off the top of my head.

 

[FreakinEurekan]

Could it? Sure, I suppose.

Will it? HIGHLY unlikely, to the point that unless you're a highly likely target you can ignore it (and if you ARE a highly likely target, asking at MacRumors is not the direction to take).

 

[chrono1081]

So what precautions should one take other than staying up to date on updates? If I want to take my MacBook to the local coffee shop and use their wifi, am I taking a serious risk?

No you are not taking a serious risk. Malware on macOS is incredibly rare and most of the "exploits" you see require physical access to a device (and it's well known that if someone has physical access to ANY device on ANY OS it could be game over for your data).

macOS has something called XCProtect that runs before the OS even boots and has signatures of all known Mac malware.

*THAT BEING SAID*, unless you're using a VPN there's always a risk of doing anything sensitive on a network that is not your own. I personally do not use public wifi for anything sensitive but rather I use the hotspot on my phone.

 

[IJustWannaTalk]

So what precautions should one take other than staying up to date on updates? If I want to take my MacBook to the local coffee shop and use their wifi, am I taking a serious risk?

No.

 

[Madonepro]

So what precautions should one take other than staying up to date on updates? If I want to take my MacBook to the local coffee shop and use their wifi, am I taking a serious risk?

You could use a VPN, or download a use the Tor browser, but as others have said, it's a risk, but quite small.

 

[Basic75]

If I want to take my MacBook to the local coffee shop and use their wifi, am I taking a serious risk?

Depends on how their Wifi is set up. If it's behind a NAT your computer can't be addressed from the internet, if not it can. If the hotspot allows all devices in the network to see each other your computer can be addressed by everybody else in the coffee shop, otherwise it can't. The biggest threat is probably through manipulated DNS, but if you care about your stuff you shouldn't be using plain old DNS over UDP anyhow.

 

[CharlesShaw]

If the hotspot allows all devices in the network to see each other your computer can be addressed by everybody else in the coffee shop, otherwise it can't.

I won't even allow my employer-managed Windows laptop to connect to my personal WiFi network, so I keep it on an isolated guest network.

 

[123123123]

I won't even allow my employer-managed Windows laptop to connect to my personal WiFi network, so I keep it on an isolated guest network.

Unfortunately, I often don’t have that luxury. I suppose my question is this: If I have an up to date Mac on a public wifi network (which could possibly have other machines with malware, whether Macs, iPads, iPhones, PCs, etc.), is my Mac at risk of contracting malware? (I see that as a separate issue from the question of whether data sent over that network is secure or not – if I want to just read the news and check the weather, That’s different from doing banking – but I’m much more worried about the prospect of somehow contracting malware from just using a public wifi network.)