Overthewire Bandit Level 16 To 17

Level goal

The credentials for the next level can be retrieved by submitting the password of the current level to **a port on localhost in the range 31000 to 32000**. First find out which of these ports have a server listening on them. Then find out which of those speak SSL and which don’t. There is only 1 server that will give the next credentials, the others will simply send back to you whatever you send to it.

Yey. Nmap. My friend from a old life hobby.

bandit16@bandit:~$ nmap localhost -p31000-32000

Starting Nmap 7.40 ( https://nmap.org ) at 2021-04-07 21:22 CEST
Nmap scan report for localhost (127.0.0.1)
Host is up (0.00025s latency).
Not shown: 996 closed ports
PORT      STATE SERVICE
31046/tcp open  unknown
31518/tcp open  unknown
31691/tcp open  unknown
31790/tcp open  unknown
31960/tcp open  unknown

Well, that didn’t help, lets add the -sV switch (all versions)

bandit16@bandit:~$ nmap localhost -p31000-32000 -sV

Starting Nmap 7.40 ( https://nmap.org ) at 2021-04-07 21:24 CEST
Stats: 0:01:28 elapsed; 0 hosts completed (1 up), 1 undergoing Service Scan
Service scan Timing: About 100.00% done; ETC: 21:25 (0:00:00 remaining)
Nmap scan report for localhost (127.0.0.1)
Host is up (0.00021s latency).
Not shown: 996 closed ports
PORT      STATE SERVICE     VERSION
31046/tcp open  echo
31518/tcp open  ssl/echo
31691/tcp open  echo
31790/tcp open  ssl/unknown
31960/tcp open  echo
1 service unrecognized despite returning data. If you know the service/version, please submit the following fingerprint at https://nmap.org/cgi-bin/submit.cgi?new-service :
SF-Port31790-TCP:V=7.40%T=SSL%I=7%D=4/7%Time=606E06F8%P=x86_64-pc-linux-gn
SF:u%r(GenericLines,31,"Wrong!\x20Please\x20enter\x20the\x20correct\x20cur
SF:rent\x20password\n")%r(GetRequest,31,"Wrong!\x20Please\x20enter\x20the\
SF:x20correct\x20current\x20password\n")%r(HTTPOptions,31,"Wrong!\x20Pleas
SF:e\x20enter\x20the\x20correct\x20current\x20password\n")%r(RTSPRequest,3
SF:1,"Wrong!\x20Please\x20enter\x20the\x20correct\x20current\x20password\n
SF:")%r(Help,31,"Wrong!\x20Please\x20enter\x20the\x20correct\x20current\x2
SF:0password\n")%r(SSLSessionReq,31,"Wrong!\x20Please\x20enter\x20the\x20c
SF:orrect\x20current\x20password\n")%r(TLSSessionReq,31,"Wrong!\x20Please\
SF:x20enter\x20the\x20correct\x20current\x20password\n")%r(Kerberos,31,"Wr
SF:ong!\x20Please\x20enter\x20the\x20correct\x20current\x20password\n")%r(
SF:FourOhFourRequest,31,"Wrong!\x20Please\x20enter\x20the\x20correct\x20cu
SF:rrent\x20password\n")%r(LPDString,31,"Wrong!\x20Please\x20enter\x20the\
SF:x20correct\x20current\x20password\n")%r(LDAPSearchReq,31,"Wrong!\x20Ple
SF:ase\x20enter\x20the\x20correct\x20current\x20password\n")%r(SIPOptions,
SF:31,"Wrong!\x20Please\x20enter\x20the\x20correct\x20current\x20password\
SF:n");

I’m going to guess it’s port 31790, lets see.

 openssl s_client --connect localhost:31790
CONNECTED(00000003)
...snip...
cluFn7wTiGryunymYOu4RcffSxQluehd
...snip...
Correct!
-----BEGIN RSA PRIVATE KEY-----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-----END RSA PRIVATE KEY-----

closed

Lets make a file in a tmp directory and save this.. Am going to use Nano because VI scares me. Copied the key and saved it.

bandit16@bandit:/tmp/zd16$ mkdir /tmp/zd16
bandit16@bandit:/tmp/zd16$ ls
pk.private

Lets try to connect!

bandit16@bandit:/tmp/zd16$ ssh bandit17@localhost -i /tmp/zd16/pk.private
Could not create directory '/home/bandit16/.ssh'.
The authenticity of host 'localhost (127.0.0.1)' can't be established.
ECDSA key fingerprint is SHA256:98UL0ZWr85496EtCRkKlo20X3OPnyPSB5tB5RPbhczc.
Are you sure you want to continue connecting (yes/no)? yes
Failed to add the host to the list of known hosts (/home/bandit16/.ssh/known_hosts).
This is a OverTheWire game server. More information on http://www.overthewire.org/wargames

@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@         WARNING: UNPROTECTED PRIVATE KEY FILE!          @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
Permissions 0644 for '/tmp/zd16/pk.private' are too open.
It is required that your private key files are NOT accessible by others.
This private key will be ignored.
Load key "/tmp/zd16/pk.private": bad permissions

Permissions… Wot? Here is the answer: https://chmodcommand.com/chmod-000/ to https://chmodcommand.com/chmod-400/

bandit16@bandit:/tmp/zd16$ chmod 400 pk.private
bandit16@bandit:/tmp/zd16$ ssh bandit17@localhost -i /tmp/zd16/pk.private

VICTORY.

The password for level 17:

redacted

On the next episode of Bandit…

ssh bandit17@localhost
redacted