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Readme. Install defaults.

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Christopher Laprise 2018-04-03 10:53:15 -04:00
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README.md
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@ -5,11 +5,12 @@ Leverage Qubes template non-persistence to enhance the guest operating system's
## vm-boot-protect.service ## vm-boot-protect.service
* Protect /home (user) executable files as immutable * Acts at VM startup before private volume /rw mounts
* Quarantine all /rw (root) configs & scripts, with Whitelisting * User: Protect /home executable files as immutable
* Root: Quarantine all /rw configs & scripts, with whitelisting
* Re-deploy custom or default files to /rw on each boot
* SHA256 checksumming guards against unwanted changes * SHA256 checksumming guards against unwanted changes
* Re-deploy custom 'default' files to /rw on each boot * Provides rescue shell on error or request
* Runs at VM start before /rw mounts
## Installing ## Installing
@ -24,7 +25,7 @@ Leverage Qubes template non-persistence to enhance the guest operating system's
- `vm-boot-protect` - Protects executables/scripts within /home/user and may be used with wide array of Qubes VMs including standalone, appVMs, netVMs, Whonix, etc. - `vm-boot-protect` - Protects executables/scripts within /home/user and may be used with wide array of Qubes VMs including standalone, appVMs, netVMs, Whonix, etc.
- `vm-boot-protect-root` - Protects /home/user as above, automatic /rw executable deactivation, whitelisting, checksumming, deployment. Works with appVMs, netVMs, etc. that are _template-based_. - `vm-boot-protect-root` - Protects /home/user as above, automatic /rw executable deactivation, whitelisting, checksumming, deployment. Works with appVMs, netVMs, etc. that are _template-based_.
CAUTION: The root option **removes** dirs /rw/config, /rw/usrlocal and /rw/bind-dirs. CAUTION: The -root option by default **removes** dirs /rw/config, /rw/usrlocal and /rw/bind-dirs!
3. Disabling the Qubes default passwordless-root is necessary for the above measures to work effectively. Here are two recommended ways (choose one): 3. Disabling the Qubes default passwordless-root is necessary for the above measures to work effectively. Here are two recommended ways (choose one):
- [Enabling auth prompt for sudo](https://www.qubes-os.org/doc/vm-sudo/#replacing-password-less-root-access-with-dom0-user-prompt) configures a simple yes/no prompt that appears in dom0. - [Enabling auth prompt for sudo](https://www.qubes-os.org/doc/vm-sudo/#replacing-password-less-root-access-with-dom0-user-prompt) configures a simple yes/no prompt that appears in dom0.
@ -34,40 +35,41 @@ Leverage Qubes template non-persistence to enhance the guest operating system's
### Usage ### Usage
Operation is automatic and will result in either a normal process with full access to the private volume at /rw, or a rescue service mode with the private volume quarantined at /mnt/rwtmp. Operation is automatic and will result in either a normal boot process with full access to the private volume at /rw, or a rescue service mode providing an xterm shell and the private volume quarantined at /dev/badxvdb.
At the `vm-boot-protect` level, certain executable files in /home will be made immutable so PATH and `alias` cannot be used to hijack commands like `su` and `sudo`, nor can impostor apps autostart whenever a VM starts. This prevents normal-privilege attacks from gaining persistence at startup. At the `vm-boot-protect` level, certain executable files in /home will be made immutable so PATH and `alias` cannot be used to hijack commands like `su` and `sudo`, nor can impostor apps autostart whenever a VM starts. This prevents normal-privilege attacks from gaining persistence at startup.
At the `vm-boot-protect-root` level, the $privdirs paths will be renamed as backups, effectively removing them from the VM startup. Then whitelisting, hash/checksumming and deployment are done (if configured). This protects VM startup from attacks that had previously achieved privilege escalation. At the `vm-boot-protect-root` level, the $privdirs paths will be renamed as backups, effectively removing them from the VM startup. Then whitelisting, hash/checksumming and deployment are done (if configured). This protects VM startup from attacks that had previously achieved privilege escalation.
The special `vm-boot-protect-cli` level unconditionally runs an xterm rescue shell.
### Configuration ### Configuration
Files can be added to /etc/default/vms in the template to enable the following features... Files can be added to /etc/default/vms in the template to enable the following features...
**Hashes/Checksums** are checked in ../vms/vms.all.SHA and ../vms/$vmname.SHA files. File paths contained in them must be absolute. See man page for `sha256sum -c`. **Hashes/Checksums** are checked in ../vms/vms.all.SHA and ../vms/$vmname.SHA files. File paths contained in them must be absolute. See man page for `sha256sum -c`.
**Whitelists** are checked in ../vms/vms.all.whitelist and ../vms/$vmname.whitelist files, and file paths contained in them must start with `/rw/`. **Whitelists** are checked in ../vms/vms.all.whitelist and ../vms/$vmname.whitelist files, and file paths contained in them must start with `/rw/`. A default is provided in ..vms/sys-net.whitelist to preserve Network Manager connections in sys-net.
**Deployment** files are copied _recursively_ from ../vms/vms.all/rw/ and ../vms/$vmname/rw/ dirs. Example is to place the .bashrc file in /etc/default/vms/vms.all/rw/home/user/.bashrc . **Deployment** files are copied _recursively_ from ../vms/vms.all/rw/ and ../vms/$vmname/rw/ dirs. Example is to place the .bashrc file in /etc/default/vms/vms.all/rw/home/user/.bashrc .
### Limitations ### Limitations
The `vm-boot-protect` concept enhances the guest operating system's own defenses by using the *root volume* non-persistence provided by the Qubes template system; thus a relatively pristine startup state may be achieved if the *private* volume is brought online in a controlled manner. Protecting the init/autostart files should result in Qubes template-based VMs that boot 'cleanly' with much less chance of being affected by malware initially. Even if malware persists in a VM, it should be possible to run other apps and terminals without interference if the malware has not escalated to root (admittedly, a big 'if'). The `vm-boot-protect` concept enhances the guest operating system's own defenses by using the *root volume* non-persistence provided by the Qubes template system; thus a relatively pristine startup state may be achieved if the *private* volume is brought online in a controlled manner. Protecting the init/autostart files should result in Qubes template-based VMs that boot 'cleanly' with much less chance of being affected by malware initially. Even if malware persists in a VM, it should be possible to run other apps and terminals without interference if the malware has not escalated to root (admittedly, a big 'if').
Conversely, attacks which damage/exploit the private filesystem itself or quickly re-exploit network vulnerabilities could conceivably still persist at startup. Repeated running of some apps such as Firefox, Chrome, LibreOffice, PDF viewers, online games, etc. may allow malware to persist in a VM; this is not only because of the complexity of the formats handled by such apps, but also because of settings contained in javascript or which specify commands to be executed by the app. Therefore, setting apps to autostart can diminish protection of the startup environment. Conversely, attacks which damage/exploit the Ext4 private filesystem itself or quickly re-exploit network vulnerabilities could conceivably still persist at startup. Further, repeated running of some apps such as Firefox, Chrome, LibreOffice, PDF viewers, online games, etc. may allow malware to persist in a VM; this is not only because of the complexity of the formats handled by such apps, but also because of settings contained in javascript or which specify commands to be executed by the app. Therefore, setting apps to autostart can diminish protection of the startup environment.
### Notes ### Notes
* The service name has been changed from `vm-sudo-protect` in pre-release to `vm-boot-protect`. The install script will automatically try to disable the old service. * The service name has been changed from `vm-sudo-protect` in pre-release to `vm-boot-protect`. The install script will automatically try to disable the old service.
* Currently if a vm-boot-protect check fails there is no immediate way to alert the user at startup. The VM will attempt to shutdown instead. See issue #7 for discussion. * All the user-writable startup files in /home should be protected by the immutable flag; See issue #9 if you notice an omission or other problem. An extra step of disabling the flag using `sudo chattr -i` whenever the user wants to modify these startup files.
* All the user-writable startup files in /home should be protected by the immutable flag; See issue #9 if you notice an omission or other problem. An extra step of disabling the flag using `sudo chattr -i` whenever the user wants to modify these startup files.
## Releases ## Releases
- v0.8.0 Adds protection to /rw, file SHA checksums, whitelists, deployment - v0.8.1 Working rescue shell. Network Manager whitelist.
- v0.2.0 Protects /home/user files and dirs - v0.8.0 Adds protection to /rw, file SHA checksums, whitelists, deployment
- v0.2.0 Protects /home/user files and dirs

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default/vms/sys-net.whitelist Normal file
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/rw/config/NM-system-connections/

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install
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#!/bin/sh #!/bin/sh
set -e
[ `id -u` -eq 0 ] || exit [ `id -u` -eq 0 ] || exit
echo "Disabling the pre-release service (if present)..." echo "Disabling the pre-release service (if present)..."
systemctl disable vm-sudo-protect.service systemctl disable vm-sudo-protect.service || true
echo "Installing vm-boot-protect.service..."
cp vm-boot-protect.sh /usr/lib/qubes/init cp vm-boot-protect.sh /usr/lib/qubes/init
chmod +x /usr/lib/qubes/init/vm-boot-protect.sh chmod +x /usr/lib/qubes/init/vm-boot-protect.sh
cp vm-boot-protect.service /lib/systemd/system cp vm-boot-protect.service /lib/systemd/system
systemctl daemon-reload systemctl daemon-reload
systemctl enable vm-boot-protect.service systemctl enable vm-boot-protect.service
echo "Adding defaults in /etc/default/vms..."
# Careful... ownership & mode are not preserved here!
cp -rnv default/vms/* /etc/default/vms
echo echo
echo "vm-boot-protect installed!" echo "vm-boot-protect installed!"