[Security] Nested Container Execution Not Sandboxed - Breakout Risk

[anshul23102]

Description

Nested container execution is not properly sandboxed. Process escaping from inner container can access the host system. Container isolation is incomplete, creating a privilege escalation vulnerability.

Steps to Reproduce

1. Start nested container (container within container)
2. Inside nested container, run: mount command
3. Can access host filesystem mounts
4. Run privileged command from nested container
5. Command executes with elevated privileges on host

Environment Information

• Container runtime: Docker or similar
• Nesting: Multi-level containers
• Isolation: Using cgroups/namespaces (incomplete)
• Privileges: Not properly isolated

Expected Behavior

• Complete namespace isolation
• No host filesystem access from nested container
• Privilege dropping in nested containers
• cgroup resource limits enforced

Actual Behavior

• Nested container can access host
• Filesystem mounts visible
• Privilege escalation possible
• Container escape risk

Code Reference

• File: daemon/container_runtime.go
• Method: createNestedContainer() - incomplete isolation
• Missing: User namespace remapping
• Missing: seccomp profile

Additional Context

Level 1 security vulnerability. Fix requires:

• Implementing user namespace remapping
• Adding seccomp sandbox
• Enforcing cgroup limits
• Security testing for container escape

Suggested Labels

security, container-isolation, sandbox, privilege-escalation, critical