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Legacy

Legacy is a fairly straightforward beginner-level machine which demonstrates the potential security risks of SMB on Windows. Only one publicly available exploit is required to obtain administrator access.

Enumeration​

Task 1​

Question

How many TCP ports are open on Legacy?

  • Performing nmap scan for open ports
╭─ ~ ─────────────────────────────────────────────────────────────────────────────────────────
╰─❯ nmap -p- -r -v -T5 10.10.10.4 | grep open
Discovered open port 135/tcp on 10.10.10.4
Discovered open port 139/tcp on 10.10.10.4
Discovered open port 445/tcp on 10.10.10.4

╭─ ~ ─────────────────────────────────────────────────────────────────────────────────────────
╰─❯ nmap -p135,139,445 -sCV -T5 10.10.10.4 -Pn
Starting Nmap 7.94SVN ( https://nmap.org ) at 2025-01-02 16:33 IST
Nmap scan report for legacy.htb (10.10.10.4)
Host is up (0.26s latency).

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 XP microsoft-ds
Service Info: OSs: Windows, Windows XP; CPE: cpe:/o:microsoft:windows, cpe:/o:microsoft:windows_xp

Host script results:
| smb-security-mode:
|   account_used: guest
|   authentication_level: user
|   challenge_response: supported
|_  message_signing: disabled (dangerous, but default)
| 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: 2025-01-07T15:00:36+02:00
|_smb2-time: Protocol negotiation failed (SMB2)
|_nbstat: NetBIOS name: LEGACY, NetBIOS user: <unknown>, NetBIOS MAC: 00:50:56:b0:dd:ff (VMware)
|_clock-skew: mean: 5d00h57m21s, deviation: 1h24m49s, median: 4d23h57m22s

Service detection performed. Please report any incorrect results at https://nmap.org/submit/ .
Nmap done: 1 IP address (1 host up) scanned in 19.72 seconds


Answer

3

Task 2​

Question

What is the 2008 CVE ID for a vulnerability in SMB that allows for remote code execution?

  • Searching for CVE ID for Windows XP (Windows 2000 LAN Manager)
$ sudo nmap  --script=smb-vuln* -T5 10.10.10.4 -Pn
Starting Nmap 7.94SVN ( https://nmap.org ) at 2025-01-02 16:42 IST
Warning: 10.10.10.4 giving up on port because retransmission cap hit (2).
Nmap scan report for legacy.htb (10.10.10.4)
Host is up (0.30s latency).
Not shown: 997 closed tcp ports (reset)
PORT    STATE SERVICE
135/tcp open  msrpc
139/tcp open  netbios-ssn
445/tcp open  microsoft-ds

Host script results:
|_smb-vuln-ms10-061: ERROR: Script execution failed (use -d to debug)
| smb-vuln-ms08-067:
|   VULNERABLE:
|   Microsoft Windows system vulnerable to remote code execution (MS08-067)
|     State: LIKELY 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://technet.microsoft.com/en-us/library/security/ms08-067.aspx
|_      https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2008-4250
|_smb-vuln-ms10-054: false
| 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://technet.microsoft.com/en-us/library/security/ms17-010.aspx
|       https://blogs.technet.microsoft.com/msrc/2017/05/12/customer-guidance-for-wannacrypt-attacks/
|_      https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-0143

Nmap done: 1 IP address (1 host up) scanned in 40.25 seconds

Answer

CVE-2008-4250

Exploitation​

Task 3​

Question

What is the name of the Metasploit module that exploits CVE-2008-4250?

  • Found exploit information here
Answer

ms08_067_netapi

Task 4​

Question

When exploiting MS08-067, what user does execution run as? Include the information before and after the .

Answer

NT AUTHORITY\SYSTEM

CTF​

  • Get user flag stored at C:\Documents and Settings\john\Desktop

  • Get root flag stored at C:\Documents and Settings\Administrator\Desktop

Extra​

Task 7​

Question

In addition to MS08-067, Legacy's SMB service is also vulnerable to another remote code execution vulnerability with a CVE ID from 2017. What is that ID?

  • This answer can be found from previous nmap script scan for smb-vuln
Answer

CVE-2017-0143