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Merged
adrelanos merged 2 commits into from
Aug 25, 2024
Merged

Provide option to disable user namespaces #263

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759aee8
Provide option to disable user namespaces
raja-grewal Aug 16, 2024
1f51d4e
Add details on user namespaces
raja-grewal Aug 18, 2024
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2 changes: 1 addition & 1 deletion README.md
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Expand Up @@ -37,7 +37,7 @@ space, user space, core dumps, and swap space.
can no longer be utilized. See [documentation](https://www.kicksecure.com/wiki/SysRq).

- Restrict user namespaces to `CAP_SYS_ADMIN` as they can lead to substantial
privilege escalation.
privilege escalation. Optional - Disable all use of user namespaces.

- Restrict kernel profiling and the performance events system to `CAP_PERFMON`.

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9 changes: 9 additions & 0 deletions usr/lib/sysctl.d/990-security-misc.conf
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Expand Up @@ -93,11 +93,20 @@ kernel.sysrq=0
## User namespaces aim to improve sandboxing and accessibility for unprivileged users.
## Unprivileged user namespaces pose substantial privilege escalation risks.
## Restricting may lead to breakages in numerous software packages.
## Uncomment the second sysctl to entirely disable user namespaces.
## Disabling entirely will reduce compatibility with some AppArmor profiles.
##
## https://lwn.net/Articles/673597/
## https://madaidans-insecurities.github.io/linux.html#kernel
## https://github.com/a13xp0p0v/kernel-hardening-checker#questions-and-answers
## https://github.com/NixOS/nixpkgs/pull/84522#issuecomment-614640601
## https://github.com/Kicksecure/security-misc/pull/263
##
## KSPP=partial
## KSPP sets the stricter sysctl user.max_user_namespaces=0.
##
kernel.unprivileged_userns_clone=0
#user.max_user_namespaces=0

## Restricts kernel profiling to users with CAP_PERFMON.
## The performance events system should not be accessible by unprivileged users.
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