TryHackMe Writeup: Blue
Upon deploying “Blue”, I was presented with an IP address of 10.10.48.149. I first began enumeration of the machine by scanning for open ports and services
nmap -sT -sU -sV -Pn 10.10.48.149
Note that although not required for the lab, I also scanned for open UDP ports. Doing this could provide me with a larger attack surface. However, UDP scans take significantly longer, and will add more time to the scan process
The resulting scan has demonstrated that SMB port 445 was open. So my next step was to see if I could enumerate both shares and users. In addition, I also wanted to scan for any SMB vulnerabilities.
nmap -p445 10.10.48.149 — script=smb-enum-users,smb-enum-shares,smb-vuln-ms17–010
The resulting scan was unable to enumerate users or shares. It did however disclose that the host was likely vulnerable to “Eternal Blue”, associated with MS17–010.
With that being noted, I decided to jump directly into exploiting the vulnerability. Worst case scenario, it would fail and I would have to continue enumerating. But if it succeeds……. Its time to fire up Metasploit.
A search for an associated exploit returned several results. I chose to start with #2
First, I prepared Metasploit with known information to prevent having to repeatedly set the same information.
setg RHOSTS 10.10.48.149
setg LHOST 10.9.240.85
Now I can select the exploit and set any additional *required* fields.
Since the required fields were already set with “setg”, this exploit was ready to run. I typed “exploit -z” and fired it off. WINNING!
In addition to gaining a shell, I also noticed I already have SYSTEM privileges
Knowing that the flags on the system were named “flag*.txt”, I ran a recursive search for those files. For the search to work as directed, I changed my current directory to C:\, then ran the search
dir /r /s flag*
The resulting search turned up 3 flags
I could read those flags by typing the following:
However, not being satisfied with just retrieving the flags, I’d also like to dump hashes so we can potentially get credentials. To do this, I have a few options. First I could run a post-exploitation module to do this. However, by going this route I am still limited in what I can do in my current context (command shell). Instead, I would like to upgrade my shell to a meterpreter shell. To do this, I backgrounded my current session with Ctrl+Z and used the following module:
Once configured, I launched the exploit and waited for my session. Once in, I ran “getuid” to see if I needed to take further action to escalate my current privs. Luckily, I already had SYSTEM
Next, we will load any and all extensions that I could find useful now that I am fully in the system. I loaded additional extensions
Now, before I try anything else, I need to make sure that I am in a 64 bit process (so kiwi can work properly). I ran the following two commands:
I observed that my PID was 2528. Cross referencing that with the process list, I realized that I was in an x86 process.
No Bueno. I need to migrate! Now I need an x64 process that is ALSO running with system privs. Looks like 480 was a good candidate…
Next, I want creds. Why? Because they could be useful should I choose to pivot and attack other endpoints. So in my meterpreter shell, I ran the following:
Awesome! I have a few hashes to crack
I decided to use crackstation. If the hashes exist there, itll take way less time than John or Hashcat. After entering the hashes, looks like it gave us Jons password!
Since this is a standalone machine, There’s not much more to do network-wise. But if I were to continue during a real engagement, I would use this machine as a pivot point and spray these creds across the network to see what else I can access.