Merge pull request #1196 from HackTricks-wiki/research_update_src_linux-hardening_privilege-escalation_docker-security_docker-breakout-privilege-escalation_sensitive-mounts_20250727_082412

Research Update Enhanced src/linux-hardening/privilege-escal...

Author: carlospolop

src/linux-hardening/privilege-escalation/docker-security/docker-breakout-privilege-escalation/sensitive-mounts.md

@@ -299,6 +299,7 @@ Mounting certain host Unix sockets or writable pseudo-filesystems is equivalent
 /run/containerd/containerd.sock     # containerd CRI socket
 /var/run/crio/crio.sock             # CRI-O runtime socket
 /run/podman/podman.sock             # Podman API (rootful or rootless)
+/run/buildkit/buildkitd.sock        # BuildKit daemon (rootful)
 /var/run/kubelet.sock               # Kubelet API on Kubernetes nodes
 /run/firecracker-containerd.sock    # Kata / Firecracker
 ```
@@ -332,7 +333,7 @@ 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
@@ -343,11 +344,17 @@ When the last process leaves the cgroup, `/tmp/pwn` runs **as root on the host**
 * **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
@@ -357,6 +364,8 @@ When the last process leaves the cgroup, `/tmp/pwn` runs **as root on the host**
 - [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)
 
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