diff --git a/src/linux-hardening/privilege-escalation/docker-security/docker-breakout-privilege-escalation/sensitive-mounts.md b/src/linux-hardening/privilege-escalation/docker-security/docker-breakout-privilege-escalation/sensitive-mounts.md index 8ab7b4b49..04c6e1140 100644 --- a/src/linux-hardening/privilege-escalation/docker-security/docker-breakout-privilege-escalation/sensitive-mounts.md +++ b/src/linux-hardening/privilege-escalation/docker-security/docker-breakout-privilege-escalation/sensitive-mounts.md @@ -89,7 +89,7 @@ echo b > /proc/sysrq-trigger # Ponownie uruchamia hosta #### **`/proc/kallsyms`** - Wymienia eksportowane symbole jądra i ich adresy. -- Niezbędne do rozwoju exploitów jądra, szczególnie w celu pokonania KASLR. +- Kluczowe dla rozwoju exploitów jądra, szczególnie w celu pokonania KASLR. - Informacje o adresach są ograniczone, gdy `kptr_restrict` jest ustawione na `1` lub `2`. - Szczegóły w [proc(5)](https://man7.org/linux/man-pages/man5/proc.5.html). @@ -114,7 +114,7 @@ echo b > /proc/sysrq-trigger # Ponownie uruchamia hosta #### **`/proc/mem`** - Alternatywny interfejs dla `/dev/mem`, reprezentujący pamięć fizyczną. -- Umożliwia odczyt i zapis, modyfikacja całej pamięci wymaga przekształcenia adresów wirtualnych na fizyczne. +- Umożliwia odczyt i zapis, modyfikacja całej pamięci wymaga rozwiązania adresów wirtualnych na fizyczne. #### **`/proc/sched_debug`** @@ -231,7 +231,8 @@ REFRESH_TOKEN_SECRET=14ea /host-var/lib/containerd/io.containerd.snapshotter.v1.overlayfs/snapshots/140/fs/usr/share/nginx/html/index.html /host-var/lib/containerd/io.containerd.snapshotter.v1.overlayfs/snapshots/132/fs/usr/share/nginx/html/index.html -/ # echo '' > /host-var/lib/containerd/io.containerd.snapshotter.v1.overlayfs/snapshots/140/fs/usr/share/nginx/html/index2.html +/ # echo '' > /host-var/lib/containerd/io.containerd.snapshotter.v1.overlayfs/snapshots/140/fs/usr/sh +are/nginx/html/index2.html ``` The XSS was achieved: @@ -270,14 +271,16 @@ Katalog główny Dockera: /var/lib/docker So the filesystems are under `/var/lib/docker/overlay2/`: ```bash +```markdown $ sudo ls -la /var/lib/docker/overlay2 -drwx--x--- 4 root root 4096 Jan 9 22:14 00762bca8ea040b1bb28b61baed5704e013ab23a196f5fe4758dafb79dfafd5d -drwx--x--- 4 root root 4096 Jan 11 17:00 03cdf4db9a6cc9f187cca6e98cd877d581f16b62d073010571e752c305719496 -drwx--x--- 4 root root 4096 Jan 9 21:23 049e02afb3f8dec80cb229719d9484aead269ae05afe81ee5880ccde2426ef4f -drwx--x--- 4 root root 4096 Jan 9 21:22 062f14e5adbedce75cea699828e22657c8044cd22b68ff1bb152f1a3c8a377f2 +drwx--x--- 4 root root 4096 Jan 9 22:14 00762bca8ea040b1bb28b61baed5704e013ab23a196f5fe4758dafb79dfafd5d +drwx--x--- 4 root root 4096 Jan 11 17:00 03cdf4db9a6cc9f187cca6e98cd877d581f16b62d073010571e752c305719496 +drwx--x--- 4 root root 4096 Jan 9 21:23 049e02afb3f8dec80cb229719d9484aead269ae05afe81ee5880ccde2426ef4f +drwx--x--- 4 root root 4096 Jan 9 21:22 062f14e5adbedce75cea699828e22657c8044cd22b68ff1bb152f1a3c8a377f2 ``` +``` #### Note @@ -293,7 +296,8 @@ Mounting certain host Unix sockets or writable pseudo-filesystems is equivalent ```text /run/containerd/containerd.sock # gniazdo CRI containerd /var/run/crio/crio.sock # gniazdo runtime CRI-O -/run/podman/podman.sock # API Podman (z uprawnieniami lub bez) +/run/podman/podman.sock # API Podman (z uprawnieniami root lub bez) +/run/buildkit/buildkitd.sock # demon BuildKit (z uprawnieniami root) /var/run/kubelet.sock # API Kubelet na węzłach Kubernetes /run/firecracker-containerd.sock # Kata / Firecracker ``` @@ -327,7 +331,7 @@ When the last process leaves the cgroup, `/tmp/pwn` runs **as root on the host** ### Mount-Related Escape CVEs (2023-2025) * **CVE-2024-21626 – runc “Leaky Vessels” file-descriptor leak** -runc ≤1.1.11 leaked an open directory file descriptor that could point to the host root. A malicious image or `docker exec` could start a container whose *working directory* is already on the host filesystem, enabling arbitrary file read/write and privilege escalation. Fixed in runc 1.1.12 (Docker ≥25.0.3, containerd ≥1.7.14). +runc ≤ 1.1.11 leaked an open directory file descriptor that could point to the host root. A malicious image or `docker exec` could start a container whose *working directory* is already on the host filesystem, enabling arbitrary file read/write and privilege escalation. Fixed in runc 1.1.12 (Docker ≥ 25.0.3, containerd ≥ 1.7.14). ```Dockerfile FROM scratch @@ -338,11 +342,17 @@ CMD ["/bin/sh"] * **CVE-2024-23651 / 23653 – BuildKit OverlayFS copy-up TOCTOU** A race condition in the BuildKit snapshotter let an attacker replace a file that was about to be *copy-up* into the container’s rootfs with a symlink to an arbitrary path on the host, gaining write access outside the build context. Fixed in BuildKit v0.12.5 / Buildx 0.12.0. Exploitation requires an untrusted `docker build` on a vulnerable daemon. +* **CVE-2024-1753 – Buildah / Podman bind-mount breakout during `build`** +Buildah ≤ 1.35.0 (and Podman ≤ 4.9.3) incorrectly resolved absolute paths passed to `--mount=type=bind` in a *Containerfile*. A crafted build stage could mount `/` from the host **read-write** inside the build container when SELinux was disabled or in permissive mode, leading to full escape at build time. Patched in Buildah 1.35.1 and the corresponding Podman 4.9.4 back-port series. + +* **CVE-2024-40635 – containerd UID integer overflow** +Supplying a `User` value larger than `2147483647` in an image config overflowed the 32-bit signed integer and started the process as UID 0 inside the host user namespace. Workloads expected to run as non-root could therefore obtain root privileges. Fixed in containerd 1.6.38 / 1.7.27 / 2.0.4. + ### Hardening Reminders (2025) 1. Bind-mount host paths **read-only** whenever possible and add `nosuid,nodev,noexec` mount options. 2. Prefer dedicated side-car proxies or rootless clients instead of exposing the runtime socket directly. -3. Keep the container runtime up-to-date (runc ≥1.1.12, BuildKit ≥0.12.5, containerd ≥1.7.14). +3. Keep the container runtime up-to-date (runc ≥ 1.1.12, BuildKit ≥ 0.12.5, Buildah ≥ 1.35.1 / Podman ≥ 4.9.4, containerd ≥ 1.7.27). 4. In Kubernetes, use `securityContext.readOnlyRootFilesystem: true`, the *restricted* PodSecurity profile and avoid `hostPath` volumes pointing to the paths listed above. ### References @@ -352,5 +362,7 @@ A race condition in the BuildKit snapshotter let an attacker replace a file that - [https://0xn3va.gitbook.io/cheat-sheets/container/escaping/sensitive-mounts](https://0xn3va.gitbook.io/cheat-sheets/container/escaping/sensitive-mounts) - [Understanding and Hardening Linux Containers](https://research.nccgroup.com/wp-content/uploads/2020/07/ncc_group_understanding_hardening_linux_containers-1-1.pdf) - [Abusing Privileged and Unprivileged Linux Containers](https://www.nccgroup.com/globalassets/our-research/us/whitepapers/2016/june/container_whitepaper.pdf) +- [Buildah CVE-2024-1753 advisory](https://github.com/containers/buildah/security/advisories/GHSA-pmf3-c36m-g5cf) +- [containerd CVE-2024-40635 advisory](https://github.com/containerd/containerd/security/advisories/GHSA-265r-hfxg-fhmg) {{#include ../../../../banners/hacktricks-training.md}}