Hello aspiring hackers. In this howto, we will see how to enumerate installed programs a Windows system after compromise. This is a POST exploit in Metasploit which means this exploit is only available when we get a meterpreter session on the target system. Once a Windows system is hacked, privilege escalation is the next step. One of the ways to escalate privileges in a Windows system would be to find vulnerabilities in the programs installed in our target Windows system. We can do this manually but Metasploit has a post module to do exactly this. Let us see how to use it.
Send the current meterpreter session to background and load the enum_applications module as shown below. Just like any other POST module, it needs only one option, the session id of the meterpreter session we just sent to background.
Set the session Id and execute the module as shown below.
As you can see, the module successfully gave us the programs installed on our victim’s system. Now we can search for any vulnerabilities in those programs which we could be used in privilege escalation. That is how we enumerate Installed programs in Windows.
Vulnerability Assessment is the process of evaluating the weakness of a system or network. It identifies the vulnerabilities in a system or network and helps black hats to devise exploits to get access to a target system or network. We developed this Vulnerability assessment by hackers article to give readers an idea as to how hackers perform vulnerability assessment. For example, imagine I am a black hat who performed a Nmap scan on the target (in this case, Metasploitable). The target has displayed so many banners of the services running.
Hello aspiring hackers. You all know about the meterpreterpayload. It is an advanced dynamically extensible payload of Metasploit. Meterpreter architecture migration exploit is a “post” exploit used to migrate from one architecture to another architecture. What is architecture? As we all know there are two main system architectures 32bit and 64bit.
Sometimes we happen to run our exploit from a 32bit machine to hack a 64bit machine or run our exploit from a 64bit machine to hack a 32bit machine. The meterpreter payload spawns a process according to the architecture of the attacking system. If the attacking system is 32bit, the meterpreter process is 32bit and if the attacking system is 64bit the meterpreter process is 64bit.
Sometimes there may be compatibility issues if we get a 32bit meterpreter session on a 64bit machine and vice versa. This is the exact reason why this module has been introduced. For example, in one of our previous howto, we hacked a 64bit machine from a 32bit Kali Linux. So we have a 32bit meterpreter session on a 64bit target system. To overcome the problems of incompatibility, we need to start a 64bit meterpreter session.
It is exactly in cases like these, this module comes handy. This module checks if the architecture of meterpreter is as same as the architecture of OS and if it is not, spawns a new process with the correct architecture and migrates into that process. Let’s see how this module works.
To use this module, we need to background the current session using command “background”. Then load the exploit as shown below. Type command “show options” to have a look at the options it requires.
We need to only set the session id of the meterpreter session we just sent to background and the exploit is good to go.
If you see in the above image, our exploit failed to run for the first time. This is because in the previous session we had system privileges and if we run this module we may lose the system privileges. But don’t worry we can change the options to overcome this problem.
Set “ignore_system” option to true and you should be fine to go. This time the exploit ran successfully. As you can see in the above image, our target is a 64bit machine and our meterpreter migrated to a 64bit process successfully. Lets check by typing command “session s -l” to see the available sessions. You can see we have a 64bit meterpreter now. Job performed.
Hello, aspiring ethical hackers. In our previous blogpost, you learnt about various techniques used for Windows privilege escalation. In this blogpost, you will learn about UAC bypass, one of the techniques used for privilege escalation in Windows. To understand UAC bypass, you need to first understand what is UAC.
What is UAC?
User Account Control (UAC) is a mandatory access control feature of Windows operating system that helps in improving the security of the operating system. It was introduced in Window Vista and Windows Server 2008 and has ben improved since then. User Account Control works by limiting a software or program to run with standard user privileges (low privileges) until and unless a user with administrator privileges authorizes it by giving permission. This way, only applications trusted by the user can be run on the system. This helps to prevent malware infection as malware and virus need administrator privileges to infect the system wholly.
How can UAC be bypassed?
Now, you have a question. How can UAC be bypassed. There are various UAC bypass methods. They are,
1. Registry key manipulation:
This technique works by hijacking the normal execution flow of an auto elevated application. What are auto-elevated applications? In Microsoft windows, if a binary is trusted (i.e. it has been signed with a MS certificate or the binary is in a trusted directory), the UAC prompt will not be presented. This can be exploited using a registry key.
The fodhelper privilege escalation method is an example of this. Fodhelper.exe is a trusted binary in Windows operating systems that is used to manage features in Windows settings. We can exploit this binary by hijacking a special key in the Registry under the current user hive and inserting a custom command that will get invoked when the Windows fodhelper.exe application is launched.
Once the UAC flag is turned off, we will spawn a second shell with SYSTEM privileges. Metasploit has a module for this. Let’s see it practically using Metasploit. Imagine we have a scenario where we have gained access to a Windows system using any Windows hacking technique.
To use the fodhelper module to elevate privileges, we need to background the current session.
Search for fodhelper module using the search command.
Load the module and set the session ID as shown below.
Run the module as shown below.
As you can see, we successfully got a meterpreter session. When I check privileges, its still user privileges but when I run “getsystem” command, I get system privileges on the target Windows system.
2. DLL hijacking:
In this method, the execution of an elevated program is hijacked using DLL Search order hijacking, DLL loading, redirection or other DLL vulnerability.
3. Elevated COM interface method:
COM stands for Component Object Model. It acts as a binary interface between various processes of different programming languages. In Windows, is is the basis for several other Microsoft technologies like OLE, OLE Automation, Browser Helper Object, ActiveX, COM+, DCOM, Windows shell, DirectX and Windows runtime. In this method, the COM handler is bypassed while it references registry when a high integrity process is being loaded. These DLLs contain the payloads that result in elevated sessions.
Let’s demonstrate this using Metasploit. As for every privilege escalation exploit, we need to already have a meterpreter session on target. This can be achieved using one of the Windows hacking techniques. Once we have it, search for the bypassuac_comhijack module as shown below.
Load the bypassuac_comhijack module and check its options by using the “show options” command as shown below.
Set the session id and execute the exploit using “run” command as shown below. If everything went right, we will have another meterpreter session as shown below.
Check the privileges using the “getuid” command. If you still don’t have system privileges, run command “getsystem” and even if it results in an error, check your privileges once again using command “getuid“. You should definitely have system privileges by now.
We have performed two types of enumeration till now. Before we perform further enumeration, let us see whether these credentials we acquired can help us in gaining access to the remote system. We will do this by hacking FTP, telnet and SSH services. When we performed a scan with Nmap during scanning and enumeration stage, we have seen that ports 21,22,23 are open and running FTP, Telnet and SSH services respectively.
FTP
FTP stands for File Transfer Protocol. As the name implies, it is used to share or transfer files. This service runs on port 21 by default. Although not quite popular now, it was the most popular way of sharing files in yesteryears. It was quite popular as torrents now, only that FTP is a client-server architecture. Since FTP is used for sharing files, it has a option to enable anonymous downloads. Anonymous download is a type of download where anyone can download the file by logging in with the username of “anonymous” and password as anything. But it a was courtesy to give your email address as password in those days. Enabling anonymous account on FTP server is considered a high security risk especially if the account given not only read but also write permissions. Another disadvantage with FTP is that it uses clear text authentication. So if any hacker is sniffing on your LAN, he can see the username and password in plain text. Ok, Since our target is running FTP service, let us first check if anonymous account is enabled on the server. We can connect to FTP server through terminal by using command “ftp target address” as shown below.
I try to login with the anonymous account with anonymous as the password and the login is successful. Good, anonymous account is enabled on the target. It’s time to check the permissions given to anonymous user.
I type command “pwd” to see the current ftp directory. It’s root directory. Next I use “put” command to upload a random file to the FTP server. As you can see in the above image, file could not be created. So anonymous account has only “read” permissions. Enabling write permissions to the anonymous account may result in propagation of malware, pirated software etc. So anonymous account is secure in this case. Next I decided to try the credentials I got during enumeration. I decided to try with “msfadmin” first. The password is also “msfadmin” for user msfadmin. Login successful. I first checked the contents of the ftp directory. It seems this account has admin rights on the FTP server.
I once again try to upload the “shell.php” into the FTP directory. This time it’s successful.
Now I can upload any malicious file to the server and can use it for any nefarious purpose. or propagation.
TELNET
Telnet is a network protocol used to remotely administer a system. It is bi-directional and interactive communication protocol. Using telnet we can remotely communicate with a system far away. It runs on port 23. We can connect to a telnet server from terminal just as we connected to a FTP server using command “telnet IP address”. Anyone who successfully logs into telnet will get a shell on the remote system. When I connected to the telnet server of our target system, I didn’t even need any enumeration as the username and password were displayed in the banner.
When I logged in with the credentials msfadmin/msfadmin, as you can see in the below image, I got a normal shell.
Although getting a shell on a remote system is good, we can perform limited operations with this type of shells. But don’t worry, we can get a meterpreter session on the remote system with the help of Metasploit, of course by exploiting telnet.
Start Metasploit and load the telnet module as shown below. Set all the options we need and execute the module by typing command “run”.
You can see that we successfully got a shell just like before. Type command “sessions” to display the sessions we have.
Metasploit provides a wonderful option to upgrade a command shell to meterpreter shell. Load the following post module and the set the session id as that of telnet shell. Run the module.
As you can see in the above image, we successfully got a meterpreter session on the metasploitable system. We can see all the sessions we have using command “sessions”.
We can interact with the session we want by using command “sessions -i id” where id is the session id number. We will see more about meterpreter in our later issues. For the first time, we gained access to the metasploitable system, although with limited privileges.
SSH
SSH stands for a secure shell. It was designed as a replacement for telnet and intended to be secure unlike telnet. SSH is a cryptographic network protocol which encrypts the data during remote communication. Thus it provides security and authentication also takes in encrypted format. Thus even if any hacker is sniffing on the local LAN, he still can’t any SSH credentials. SSH by default runs on port 22. Just like it has a telnet module, Metasploit also has a SSH login module. We will use the same credentials msfadmin/msfadmin to login. Load the SSH login module as shown below and configure required options.
Once all the options are set, run the module as shown below.
We have a successful login. Same as above, we can use “sessions” command to view the available sessions. We can also upgrade this SSH shell to meterpreter just as we did in the case of telnet. That was about hacking FTP, telnet and SSH. Learn something advanced hacking with HTA Webserver Exploit
What We Achieved:
Using the details we gathered during enumeration, we have hacked some services on the Metasploitable system. We have also gained shell and meterpreter session on the system.
