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The ‘app’ you can’t trash: how SIP is broken in High Sierra

eclecticlight.co

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Re: The ‘app’ you can’t trash: how SIP is broken in High Sierra

#11
post #3

> when some malware does manage to slip an evil kernel extension past a user and is rewarded with the protection of SIP, neither the user nor any anti-malware tool will be able to remove that extension, unless the user restarts from a different boot volume, or KernelExtensionManagement allows it. But isn't that scenario "Game Over" anyway? At least installing kernel extensions is a process that is explicit and - impo…

You can not trust the user. Never.

Re: The ‘app’ you can’t trash: how SIP is broken in High Sierra

#12
post #7

Applying SIP on the KEXT makes sense, since any KEXT that’s writable by the user is a huge security risk. The only thing that appears to be broken here is the BlueStack uninstaller that is apparently not SIP-aware. There’s probably some way to do the SIP procedure you did to install the app in reverse.

The point of the article is that there's no documented way to do the SIP procedure in reverse.

Re: The ‘app’ you can’t trash: how SIP is broken in High Sierra

#13
git and other utilities are installed in SIP protected directories. Or are they? Actually, Apple installs shims for these tools that call on xcoderun, which runs the utilities in other XCode specific locations.

Just for shits and giggles, I used these Xcode shims to do a stupid hack:

http://randomtechnicalstuff.blogspot.com.au/2016/05/os-x-and...

Re: The ‘app’ you can’t trash: how SIP is broken in High Sierra

#14
post #3

> when some malware does manage to slip an evil kernel extension past a user and is rewarded with the protection of SIP, neither the user nor any anti-malware tool will be able to remove that extension, unless the user restarts from a different boot volume, or KernelExtensionManagement allows it. But isn't that scenario "Game Over" anyway? At least installing kernel extensions is a process that is explicit and - impo…

> not just another 'trained to ignore' permissions dialog.

I have never seen any user reading a dialog message if it has a button with label "ok", "cancel", "allow" or "next". Including a lot of developers/dev-ops.

Re: The ‘app’ you can’t trash: how SIP is broken in High Sierra

#15
post #3

> when some malware does manage to slip an evil kernel extension past a user and is rewarded with the protection of SIP, neither the user nor any anti-malware tool will be able to remove that extension, unless the user restarts from a different boot volume, or KernelExtensionManagement allows it. But isn't that scenario "Game Over" anyway? At least installing kernel extensions is a process that is explicit and - impo…

> not just another 'trained to ignore' permissions dialog. I have never seen any user reading a dialog message if it has a button with label "ok", "cancel", "allow" or "next". Including a lot of developers/dev-ops.

This seems a bit hyperbolic. I do, and I'm pretty sure a lot of people do - especially developers; and especially dialogs that you didn't explicitly expect.

Not saying that the majority do; or that a dialog is "good security protection". I just don't think it's as useless as you seem to imply.

Re: The ‘app’ you can’t trash: how SIP is broken in High Sierra

#16
post #15

Earlier quoted context omitted.

> not just another 'trained to ignore' permissions dialog. I have never seen any user reading a dialog message if it has a button with label "ok", "cancel", "allow" or "next". Including a lot of developers/dev-ops.

This seems a bit hyperbolic. I do, and I'm pretty sure a lot of people do - especially developers; and especially dialogs that you didn't explicitly expect. Not saying that the majority do; or that a dialog is "good security protection". I just don't think it's as useless as you seem to imply.

It’s exaggerated but only slightly. Some of the worst messes I’ve seen were people who should have known better just blindly pasting google search results because they didn’t have time to do it right.

More developers than sysadmins but definitely not exclusively so. Never underestimate the degree to which people are rushing or not questioning whether their initial diagnosis was correct.

Re: The ‘app’ you can’t trash: how SIP is broken in High Sierra

#17
post #3

> when some malware does manage to slip an evil kernel extension past a user and is rewarded with the protection of SIP, neither the user nor any anti-malware tool will be able to remove that extension, unless the user restarts from a different boot volume, or KernelExtensionManagement allows it. But isn't that scenario "Game Over" anyway? At least installing kernel extensions is a process that is explicit and - impo…

You can not trust the user. Never.

How does that work in parallel with "It's my device, I'll do what I want with it"?

Re: The ‘app’ you can’t trash: how SIP is broken in High Sierra

#18
This post annoys me for describing a problem which other people might encounter with a good level of detail but uses “broken” to get clicks rather than the more accurate “I don’t understand or agreee with the security model”.

As misnome and others have noted, if someone loads a malicious kext the only safe option is a complete wipe and reinstall – or depending on how much you trust Apple’s firmware signing, buying a new computer.

This is part and parcel of working in a higher security environment than the classic Unix model, and it’s not specific to MacOS. I’ve seen people have the same kind of angry rants about trying to delete immutable files on other Unixes, disabling SELinix rather than learning how to use it and then complaining when an auditor dinged it (on .gov systems!), etc. I think it’s generational for those of us who got started on single-user PCs in the early or pre-internet era and learned the root=god model as the default without questioning its suitability for general usage or the modern malware situation (broad targeting, sophisticated, omnipresent, infections can be permanent, etc.).

Re: The ‘app’ you can’t trash: how SIP is broken in High Sierra

#20
post #3

> when some malware does manage to slip an evil kernel extension past a user and is rewarded with the protection of SIP, neither the user nor any anti-malware tool will be able to remove that extension, unless the user restarts from a different boot volume, or KernelExtensionManagement allows it. But isn't that scenario "Game Over" anyway? At least installing kernel extensions is a process that is explicit and - impo…

> not just another 'trained to ignore' permissions dialog. I have never seen any user reading a dialog message if it has a button with label "ok", "cancel", "allow" or "next". Including a lot of developers/dev-ops.

The dialog for kernel extension doesn't contain any of those labels though. Instead it offers you to open the "Security" preference pane where some additional UI will be displayed.

If you blindly click buttons you will not accidentally enable a kernel extension.

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