mirror of
https://github.com/YunoHost/doc.git
synced 2024-09-03 20:06:26 +02:00
124 lines
4.6 KiB
Markdown
124 lines
4.6 KiB
Markdown
# Security
|
|
|
|
YunoHost has been developed to provide the best security without too much complication. Every protocol used in YunoHost are **encrypted**, only password's hash are stored and by default each user is able to access to his personal directory only.
|
|
|
|
Two things remain important to note:
|
|
|
|
* Installing additional apps can **increase significantly** the number of potential security flaws. Do not hesitate to get information about them **before using it**, and try to install only those which will suit your needs.
|
|
|
|
* The fact that YunoHost is a well-spread software increase chances to face an attack. If a flaw is discovered, it could potentially affect all the YunoHost instances at once. Keep your system **up-to-date** to remain safe.
|
|
|
|
*If you need some advises, do not hesitate to [ask us](/support).*
|
|
|
|
---
|
|
|
|
## Improve security
|
|
If your YunoHost server is used in a critical production environment, or if you want to improve its safety, you may want to follow those good practices.
|
|
|
|
**Attention:** *Following those instructions requires advanced knowledges in system administration.*
|
|
|
|
### SSH authentication via key
|
|
By default, the SSH authentication uses the administration password. Deactivation this kind of authentication and replacing it by a key mechanism is advised.
|
|
|
|
**On your client**:
|
|
|
|
```bash
|
|
ssh-keygen
|
|
ssh-copy-id -i ~/.ssh/id_rsa.pub <your_yunohost_server>
|
|
```
|
|
|
|
Type your admnistration password and your key will be copied on your server.
|
|
|
|
**On your server**, edit the SSH configuration file, in order to deactivate the password authentication.
|
|
|
|
```bash
|
|
nano /etc/ssh/sshd_config
|
|
|
|
# Modify or add the following line
|
|
PasswordAuthentication no
|
|
```
|
|
|
|
Save and restart SSH daemon.
|
|
|
|
---
|
|
|
|
### Modify SSH port
|
|
|
|
To prevent SSH connection attempts by robots that scan the Internet for any attempt SSH connections with any server accessible, you can change the SSH port.
|
|
|
|
**On your server**, edit the ssh configuration file, in order to modify SSH port.
|
|
|
|
```bash
|
|
nano /etc/ssh/sshd_config
|
|
|
|
# Search line "Port" and remplace port number (by default 22) by another not used number
|
|
Port 22 # to replace by 9777 for example
|
|
```
|
|
|
|
Save and restart SSH daemon.
|
|
|
|
Then restart the iptables firewall and close the old port in iptables.
|
|
|
|
```bash
|
|
yunohost firewall reload
|
|
yunohost firewall disallow <your_old_ssh_port_number> # port by default 22
|
|
yunohost firewall disallow --ipv6 TCP <your_new_ssh_port_number> # for ipv6
|
|
```
|
|
|
|
**For the next SSH connections ** you need to add the `-p` option followed by the SSH port number.
|
|
|
|
**Sample**:
|
|
|
|
```bash
|
|
ssh -p <new_ssh_port_number> admin@<your_yunohost_server>
|
|
```
|
|
|
|
---
|
|
|
|
### Change the user authorized to connect via SSH
|
|
|
|
To avoid multiple forcing the admin login attempts by robots, it can possibly change the authorized user to connect.
|
|
|
|
<div class="alert alert-info" markdown="1">
|
|
In the case of a key authentication, brute force has no chance of succeeding. This step is not really useful in this case
|
|
</div>
|
|
|
|
**On your server**, add a user
|
|
```bash
|
|
sudo adduser user_name
|
|
```
|
|
Choose a strong password, since it is the user who will be responsible to obtain root privileges.
|
|
Add the user to sudo group so just to allow him to perform maintenance tasks that require root privileges.
|
|
```bash
|
|
sudo adduser user_namesudo
|
|
```
|
|
|
|
Now, change the SSH configuration to allow the new user to connect.
|
|
**On your server**, edit the SSH configuration file
|
|
```bash
|
|
sudo nano /etc/ssh/sshd_config
|
|
|
|
# Look for the section "Authentication" and add at the end of it:
|
|
AllowUsers user_name
|
|
```
|
|
Only users listed in the AllowUsers directive will then be allowed to connect via SSH, which excludes the admin user.
|
|
|
|
Save and restart SSH daemon.
|
|
|
|
---
|
|
|
|
### Disable YunoHost API
|
|
YunoHost administration is accessible through an **HTTP API**, served on the 6787 port by default. It can be used to administrate a lot of things on your server, thus to break many things between malicious hands. The best thing to do, if you know how to use the [command-line interface](/moulinette), is to deactivate the `yunohost-api` service.
|
|
|
|
```bash
|
|
sudo service yunohost-api stop
|
|
```
|
|
|
|
### YunoHost penetration test
|
|
|
|
Some [pentests](https://en.wikipedia.org/wiki/Penetration_test) have been done on a YunoHost 2.4 instance (french):
|
|
|
|
- [1) Preparation](https://blog.exadot.fr/2016/07/03/pentest-dune-instance-yunohost-1-preparation)
|
|
- [2) The functionning](https://blog.exadot.fr/2016/07/12/pentest-dune-instance-yunohost-2-le-fonctionnement)
|
|
- [3) Black Box Audit](https://blog.exadot.fr/2016/08/26/pentest-dune-instance-yunohost-3-audit-en-black-box)
|
|
- [4) Grey Box Audit](https://blog.exadot.fr/2016/11/03/pentest-dune-instance-yunohost-4-audit-en-grey-box)
|