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Comment by b212 | Hacker News Reader

Apple puts so much pressure on security, shouldn't it be possible to block ransomware somehow on the OS level, possibly on all platforms?

I mean not many apps need to modify millions of files on all drives including network drives and dongles... It should be fairly easy to spot, something like:

1. If xxx wants to modify more than 50 files in 24 hours go to 2.

2. If some of the files were modified more than a week ago or if the files are in directories across multiple drives go to 3.

3. If some of the files are images/documents it's a no go, prompt user to accept and list the affected files.

I'd love something like this for my Synology, it's connected to my Macbook as a network drive and I store my backups there, if anything modifies these files without my knowledge I'm doomed. I need to access some of my backups on daily basis so it's kinda hard to disconnect te drive all the time :/

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Windows 10 has just what you describe: https://www.bleepingcomputer.com/news/microsoft/how-to-enabl...

Of course, bad guys still can 1) create encrypted copy and delete originals instead of modifying files in place; 2) disable protection alongside with A/V and proceed as usual; and my favorite 3) rely on built-in disk encryption mechanisms and simply overwrite encryption keys & salts.

> Windows 10 has just what you describe [link]

I've looked into this, but it feels limited to me. It's all or nothing. I can't have App1 only access Documents and App2 only access Pictures. Once I give any one app access to the "protected folders", it has access to all the protected folders.

Yes, it's does not give you SELinux/seccomp level of granularity. But then again, there is a slight chance that users might actually understand what it's for and how to use it, unlike SELinux/seccomp.

In practice though, if you're a power user you probably won't run shady binaries, and if you do - nothing will protect you from them as your user is likely a member of administrative group / wheel and you use sudo/su/doas somewhat regularly. While if you're worried about protecting your employees/family members, just making sure they are not part of the same admin groups and enforcing basic Software Restriction Policy / AppLocker / SELinux / RBAC will be enough to protect against 99% threats out there.

I agree that SELinux is much too complex for "regular people".

However, the issue I see with this approach is that the default location for saving pretty much everything on Windows is the Documents folder. So I think most people would just blindly agree to give access to this folder.

Most malware comes from apps people wilfully install, so they would probably grant them access to the folders because they would want to use them.

The approach I like best is what MacOS does, where you have to approve access to a specific folder. The drawback of the MacOS implementation is that I cannot define specific folders I want protected (say .ssh).

I agree, at least an option to have more granularity would be a good thing. Maybe the upcoming changes to Android/iOS permission models will solve the problem of UI/UX and this will finally become fashionable.

However, there is also a question of properly enforcing granular per-process restrictions (without breaking backwards compatibility). It's not a trivial task, there are plenty of corner cases: race conditions, symlinks, alternate data streams, process hollowing... I don't expect any implementation to be full-proof in the first decade.

You should check out Qubes OS. https://www.qubes-os.org/

All applications run inside a VM, and you set up different VMs for different tasks. The windows are all composited onto one seamless desktop environment, with the colour of the window decorations telling you which VM it's in. You can copy and paste between the VMs with a special keyboard shortcut, and you can manually copy files between them as well, but otherwise they have no access to each other.

If you open some ransomware in one VM, it can't touch (or read, or know of the existence of) any of the data in other VMs.

How is usability? It’s a very appealing model but it sounds confusing

That's what I've been wondering too, especially now when more and more applications are starting to use hardware graphics acceleration.

It's great at what it does. Much more useful than I expected, feels more thought out than some commercial alternatives.

XEN Virtualization with their custom X-passthrough driver is super fast as well. No hardware acceleration of course, but it didn't feel choppy at all. As long as you have enough RAM (I'd say 16GB at least), it works pretty much like bare metal (even though there are several VMs running in background at all times for network, fw, usb, etc), way faster than Spice, VNC, RDP or Virtualbox (talking about UI not number crunching).

I used it briefly but found interacting with weird USB devices (mainly Arduino and RTL-SDR) slightly too annoying.

The first thing that happened when I enabled this, is that VMWare Workstation (a signed app that passes smartscreen stuff) was denied access to its data folder in the documents folder. No notification from Windows.

Not a good first impression, and I don't really want to learn the file access patterns of all the things I use.

> 2) disable protection alongside with A/V and proceed as usual

How would the malware do that? I've looked into this and with Windows 10 1903 onward, Tamper Protection is enabled by default. [1]

I have yet to find a programmatic method to disable Tamper Protection (which is a prerequisite to disable Defender). I've tried regedit (permission denied), GPO, and all other manner of PowerShell thuggery, but I have not succeeded. In the end, I scripted extracting and editing the registry hive offline (outside the VM) to disable Tamper Protection.

Unless the malware has a way to open the Settings app and toggle Tamper Protection in the UI as if they were a user, I can't think of any way they could disable it unless they exploit a known weakness in Defender or a third-party anti-virus program (entirely possible).

[1] https://docs.microsoft.com/en-us/windows/security/threat-pro...

Tamper protection is really meant for enterprise. Disabling it is exactly as hard as gaining privilege escalation. It is harder to achieve in AD (of course attackers gain lateral movement opportunities instead, but that's a different story), so Tamper protection makes sense there as an additional "security in depth" layer. At home where the logged in user is likely an admin already (even if "protected" by run as / UAC), tamper protection doesn't really add much apart from breaking existing exploit kits and requiring attackers to invest into new ones.

That seems like something different - macOS already protects access to stuff like the Documents and Photos folders, etc out of the box (you have to give permission on first run, everyone complained that macOS has turned into Vista).

But if you thought the app was good and granted it access and it then goes wild...

Just quickly thinking of where there might be a lot of images/documents modified quickly: web browser cache, photo management software, antivirus software.

I think it'd be easier to isolate applications and data like Cubes OS instead of trying to create a universal rule set.

https://www.qubes-os.org/intro/

There's a fantastic free tool called RansomWhere by Objective-See that I use to monitor the rapid creation of encrypted files on my Mac. It notifies me from time to time during installation processes that something possibly malicious is going on.

Link: https://objective-see.com/products/ransomwhere.html

Is there anything like this for Windows, where most ransomware thrives?

This is why offline backups are important. Ransomware can't do anything with a drive that isn't running. Having an external hard drive that you need to physically plug and unplug once/twice/etc a week might sound inconvenient, but it solves your potential issue.

Are there any versions of malware that sit and wait for several months so that once you have it in your backups it sits and waits for you to save over your old back up and then starts it’s thing? Then if you restore from that backup you have the malware sitting waiting again to start.

Can that be worked around by having extra backups with only non executable files? Like txt, png, cpp (but without compiling and running)?

I have a vague memory of ransomware that waited for one to mount external disks yes, but not as advanced as they ones you mentioned

How would that work? If it didn't encrypt your active storage, then the backups wouldn't be encrypted either, right? Or would it somehow interfere with the backups, making you think the backup's OK when it actually is just garbage and then encrypt your active drive when no more usable backups exist?

I guess that's one reason why if you don't try restoring from you backups it's as good as not having any...

Yep:

- External drive with a bootable backup (Carbon Copy Cloner)

- Network drive with automagical Time Machine backups

- Offsite versioned backups (for example Backblaze)

"Pride goes before destruction, and a haughty spirit before a fall", but I'd be surprised if I ever will lose a file like this.

The current macOS already has great ransomware protections in the form of per-app, per-directory file access permissions.

Don’t let apps access “files on external volumes” or “files on removable media” or whatever it calls it on the popup when an app first tries to access those.

Consider replicating your Synology to a cloud service. Ransomware isn't your only risk here, burglary or fire could also leave you without your backups.

Read only filesystem snapshots (that can be restored quickly) are the best way to prevent ransomware IMPO. The snapshots can't be over-written or modified and the user can restore them whenever they like.

You may want to consider archiving some of those backups to an external drive that is only hooked up to store new data maybe? Or maybe theres something you can do for the network drive

Append-only external disk, is there sth like that?

And one flips a hardware switch to start overwriting from the beginning, if disk full

I think a network based one in theory should be capable of doing so with the right OS / configuration, but not sure about a hardware based one

https://en.wikipedia.org/wiki/Write_once_read_many

This is the acronym I saw on HN somewhere though, WORM.

Edit: Upon further research its kind of annoying that this isn't more common for NAS / cloud storage solutions. I think some like Dropbox do keep revisions on the other hand.

Syncthing can save revisions, and is open source -- I remember now

https://docs.syncthing.net/users/versioning.html

Lots of config options

Just out of curiosity, can you clarify on "I need to access some of my backups on daily basis"?

Time Machine (I don't know if that is what they are talking about, but it's an example) is designed to be used daily as well as in case your laptop explodes. Opening Time Machine allows you to go back and see every version of a file as long as your backup drive was connected when you saved it.

So each NPM\YARN install will fail... We need an API that we can extend as much as we want...

> each NPM\YARN install will fail

No -- that only writes to sub dirs

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