So at first we we have to do a nmap scan on our machine and the results for that are →

Nmap Results →

Nmap scan report for Host is up (0.050s latency). Not shown: 65429 closed ports, 100 filtered ports PORT STATE SERVICE VERSION 21/tcp open ftp vsftpd 3.0.3 22/tcp open ssh OpenSSH 7.2p2 Ubuntu 4ubuntu2.7 (Ubuntu Linux; protocol 2.0) | ssh-hostkey: | 2048 5a:4f:fc:b8:c8:76:1c:b5:85:1c:ac:b2:86:41:1c:5a (RSA) | 256 ac:9d:ec:44:61:0c:28:85:00:88:e9:68:e9:d0:cb:3d (ECDSA) |_ 256 30:50:cb:70:5a:86:57:22:cb:52:d9:36:34:dc:a5:58 (ED25519) 139/tcp open netbios-ssn Samba smbd 3.X - 4.X (workgroup: WORKGROUP) 445/tcp open netbios-ssn Samba smbd 4.3.11-Ubuntu (workgroup: WORKGROUP) 3128/tcp open http-proxy Squid http proxy 3.5.12 |_http-server-header: squid/3.5.12 |_http-title: ERROR: The requested URL could not be retrieved 3333/tcp open http Apache httpd 2.4.18 ((Ubuntu)) |_http-server-header: Apache/2.4.18 (Ubuntu) |_http-title: Vuln University No exact OS matches for host (If you know what OS is running on it, see ). TCP/IP fingerprint: OS:SCAN(V=7.80%E=4%D=5/17%OT=21%CT=1%CU=31134%PV=Y%DS=2%DC=T%G=Y%TM=5EC1487 OS:5%P=x86_64-pc-linux-gnu)SEQ(SP=FC%GCD=1%ISR=107%TI=Z%CI=I%II=I%TS=8)OPS( OS:O1=M508ST11NW7%O2=M508ST11NW7%O3=M508NNT11NW7%O4=M508ST11NW7%O5=M508ST11 OS:NW7%O6=M508ST11)WIN(W1=68DF%W2=68DF%W3=68DF%W4=68DF%W5=68DF%W6=68DF)ECN( OS:R=Y%DF=Y%T=40%W=6903%O=M508NNSNW7%CC=Y%Q=)T1(R=Y%DF=Y%T=40%S=O%A=S+%F=AS OS:%RD=0%Q=)T2(R=N)T3(R=N)T4(R=Y%DF=Y%T=40%W=0%S=A%A=Z%F=R%O=%RD=0%Q=)T5(R= OS:Y%DF=Y%T=40%W=0%S=Z%A=S+%F=AR%O=%RD=0%Q=)T6(R=Y%DF=Y%T=40%W=0%S=A%A=Z%F= OS:R%O=%RD=0%Q=)T7(R=Y%DF=Y%T=40%W=0%S=Z%A=S+%F=AR%O=%RD=0%Q=)U1(R=Y%DF=N%T OS:=40%IPL=164%UN=0%RIPL=G%RID=G%RIPCK=G%RUCK=G%RUD=G)IE(R=Y%DFI=N%T=40%CD= OS:S)

Network Distance: 2 hops Service Info: Host: VULNUNIVERSITY; OSs: Unix, Linux; CPE: cpe:/o:linux:linux_kernel

Host script results: |clock-skew: mean: 1h19m58s, deviation: 2h18m34s, median: -2s |nbstat: NetBIOS name: VULNUNIVERSITY, NetBIOS user: <unknown>, NetBIOS MAC: <unknown> (unknown) | smb-os-discovery: | OS: Windows 6.1 (Samba 4.3.11-Ubuntu) | Computer name: vulnuniversity | NetBIOS computer name: VULNUNIVERSITY\x00 | Domain name: \x00 | FQDN: vulnuniversity | System time: 2020-05-17T10:21:37-04:00 | smb-security-mode: | account_used: guest | authentication_level: user | challenge_response: supported | message_signing: disabled (dangerous, but default) | smb2-security-mode: | 2.02: |_ Message signing enabled but not required | smb2-time: | date: 2020-05-17T14:21:36 |_ start_date: N/A

Directory Busting

After directory busting we gain knowledge about a directory called internal which we can use to upload files to the server and it works for us .Now we have to upload a php fie on there but first we have to check what file type works on the site and what all can be uploaded cause as we can see the php file wont be uploaded we can try intercepting our request by burp suite and then try a list of file extensions and see which one is being uploaded and we find out that phtml is the one we can upload and then we download a php reverse shell and change our IP and port in it and then change extension to phtml and listen with netcat on the port we are using after we do that we can go to internal/uploads/shellanme.phtml and then that would pop a shell for us.

Privilege Escalation