This implementation in rust, contains a fast cpu emulator than can execute one million instructions in less than two seconds. And a simple genetic algorithm to do the evolution.
Here we create the genetic algorithm, and configure a population of 1000 individuals, and the top 5 to crossover. We run the genetic algorithm with 500 cycles maximum. Note that in this case the population are programs initially random until take the correct shape.
An evaluation function is provided in the run method as well, and looks like this:
The evaluation function receives a CPU object, to compute a test you need to set the initial parameters, run the program and set a scoring regarding the return value.
What is BurpSuite? Burp Suite is a Java based Web Penetration Testing framework. It has become an industry standard suite of tools used by information security professionals. Burp Suite helps you identify vulnerabilities and verify attack vectors that are affecting web applications. Because of its popularity and breadth as well as depth of features, we have created this useful page as a collection of Burp Suite knowledge and information.
In its simplest form, Burp Suite can be classified as an Interception Proxy. While browsing their target application, a penetration tester can configure their internet browser to route traffic through the Burp Suite proxy server. Burp Suite then acts as a (sort of) Man In The Middle by capturing and analyzing each request to and from the target web application so that they can be analyzed.
Everyone has their favorite security tools, but when it comes to mobile and web applications I've always found myself looking BurpSuite . It always seems to have everything I need and for folks just getting started with web application testing it can be a challenge putting all of the pieces together. I'm just going to go through the installation to paint a good picture of how to get it up quickly.
BurpSuite is freely available with everything you need to get started and when you're ready to cut the leash, the professional version has some handy tools that can make the whole process a little bit easier. I'll also go through how to install FoxyProxy which makes it much easier to change your proxy setup, but we'll get into that a little later.
Requirements and assumptions:
Mozilla Firefox 3.1 or Later Knowledge of Firefox Add-ons and installation The Java Runtime Environment installed
Download BurpSuite from http://portswigger.net/burp/download.htmland make a note of where you save it.
on for Firefox from https://addons.mozilla.org/en-US/firefox/addon/foxyproxy-standard/
If this is your first time running the JAR file, it may take a minute or two to load, so be patient and wait.
Video for setup and installation.
You need to install compatible version of java , So that you can run BurpSuite.
How do I get started with bug bounty hunting? How do I improve my skills?
These are some simple steps that every bug bounty hunter can use to get started and improve their skills:
Learn to make it; then break it! A major chunk of the hacker's mindset consists of wanting to learn more. In order to really exploit issues and discover further potential vulnerabilities, hackers are encouraged to learn to build what they are targeting. By doing this, there is a greater likelihood that hacker will understand the component being targeted and where most issues appear. For example, when people ask me how to take over a sub-domain, I make sure they understand the Domain Name System (DNS) first and let them set up their own website to play around attempting to "claim" that domain.
Read books. Lots of books. One way to get better is by reading fellow hunters' and hackers' write-ups. Follow /r/netsec and Twitter for fantastic write-ups ranging from a variety of security-related topics that will not only motivate you but help you improve. For a list of good books to read, please refer to "What books should I read?".
Join discussions and ask questions. As you may be aware, the information security community is full of interesting discussions ranging from breaches to surveillance, and further. The bug bounty community consists of hunters, security analysts, and platform staff helping one and another get better at what they do. There are two very popular bug bounty forums: Bug Bounty Forum and Bug Bounty World.
Participate in open source projects; learn to code. Go to https://github.com/explore or https://gitlab.com/explore/projects and pick a project to contribute to. By doing so you will improve your general coding and communication skills. On top of that, read https://learnpythonthehardway.org/ and https://linuxjourney.com/.
Help others. If you can teach it, you have mastered it. Once you discover something new and believe others would benefit from learning about your discovery, publish a write-up about it. Not only will you help others, you will learn to really master the topic because you can actually explain it properly.
Smile when you get feedback and use it to your advantage. The bug bounty community is full of people wanting to help others so do not be surprised if someone gives you some constructive feedback about your work. Learn from your mistakes and in doing so use it to your advantage. I have a little physical notebook where I keep track of the little things that I learnt during the day and the feedback that people gave me.
Learn to approach a target. The first step when approaching a target is always going to be reconnaissance — preliminary gathering of information about the target. If the target is a web application, start by browsing around like a normal user and get to know the website's purpose. Then you can start enumerating endpoints such as sub-domains, ports and web paths.
A woodsman was once asked, "What would you do if you had just five minutes to chop down a tree?" He answered, "I would spend the first two and a half minutes sharpening my axe." As you progress, you will start to notice patterns and find yourself refining your hunting methodology. You will probably also start automating a lot of the repetitive tasks.
Printers belong arguably to the most common devices we use. They are available in every household, office, company, governmental, medical, or education institution.
From a security point of view, these machines are quite interesting since they are located in internal networks and have direct access to sensitive information like confidential reports, contracts or patient recipes.
TL;DR: In this blog post we give an overview of attack scenarios based on network printers, and show the possibilities of an attacker who has access to a vulnerable printer. We present our evaluation of 20 different printer models and show that each of these is vulnerable to multiple attacks. We release an open-source tool that supported our analysis: PRinter Exploitation Toolkit (PRET) https://github.com/RUB-NDS/PRET
Full results are available in the master thesis of Jens Müller and our paper.
Furthermore, we have set up a wiki (http://hacking-printers.net/) to share knowledge on printer (in)security. The highlights of the entire survey will be presented by Jens Müller for the first time at RuhrSec in Bochum.
Background
There are many cool protocols and languages you can use to control your printer or your print jobs. We assume you have never heard of at least half of them. An overview is depicted in the following figure and described below.
Device control
This set of languages is used to control the printer device. With a device control language it is possible to retrieve the printer name or status. One of the most common languages is the Simple Network Management Protocol (SNMP). SNMP is a UDP based protocol designed to manage various network components beyond printers as well, e.g. routers and servers.
Printing channel
The most common network printing protocols supported by printer devices are the Internet Printing Protocol (IPP), Line Printer Daemon (LPD), Server Message Block (SMB), and raw port 9100 printing. Each protocol has specific features like print job queue management or accounting. In our work, we used these protocols to transport malicious documents to the printers.
Job control language
This is where it gets very interesting (for our attacks). A job control language manages printer settings like output trays or paper size. A de-facto standard for print job control is PJL. From a security perspective it is very useful that PJL is not limited to the current print job as some settings can be made permanent. It can further be used to change the printer's display or read/write files on the device.
Page description language
A page description language specifies the appearance of the actual document. One of the most common 'standard' page description languages is PostScript. While PostScript has lost popularity in desktop publishing and as a document exchange format (we use PDF now), it is still the preferred page description language for laser printers. PostScript is a stack-based, Turing-complete programming language consisting of about 400 instructions/operators. As a security aware researcher you probable know that some of them could be useful. Technically spoken, access to a PostScript interpreter can already be classified as code execution.
Attacks
Even though printers are an important attack target, security threats and scenarios for printers are discussed in very few research papers or technical reports. Our first step was therefore to perform a comprehensive analysis of all reported and published attacks in CVEs and security blogs. We then used this summary to systematize the known issues, to develop new attacks and to find a generic approach to apply them to different printers. We estimated that the best targets are the PostScript and PJL interpreters processing the actual print jobs since they can be exploited by a remote attacker with only the ability to 'print' documents, independent of the printing channel supported by the device.
We put the printer attacks into four categories.
Denial-of-service (DoS)
Executing a DoS attack is as simple as sending these two lines of PostScript code to the printer which lead to the execution of an infinite loop:
Other attacks include:
Offline mode. The PJL standard defines the OPMSG command which 'prompts the printer to display a specified message and go offline'.
Physical damage. By continuously setting the long-term values for PJL variables, it is possible to physically destroy the printer's NVRAM which only survives a limited number of write cycles.
Showpage redefinition. The PostScript 'showpage' operator is used in every document to print the page. An attacker can simply redefine this operator to do nothing.
Protection Bypass
Resetting a printer device to factory defaults is the best method to bypass protection mechanisms. This task is trivial for an attacker with local access to the printer, since all tested devices have documented procedures to perform a cold reset by pressing certain key combinations. However, a factory reset can be performed also by a remote attacker, for example using SNMP if the device complies with RFC1759 (Printer MIB):
Other languages like HP's PML, Kyocera's PRESCRIBE or even PostScript offer similar functionalities.
Furthermore, our work shows techniques to bypass print job accounting on popular print servers like CUPS or LPRng.
Print Job Manipulation
Some page description languages allow permanent modifications of themselves which leads to interesting attacks, like manipulating other users' print jobs. For example, it is possible to overlay arbitrary graphics on all further documents to be printed or even to replace text in them by redefining the 'showpage' and 'show' PostScript operators.
Information Disclosure
Printing over port 9100 provides a bidirectional channel, which can be used to leak sensitive information. For example, Brother based printers have a documented feature to read from or write to a certain NVRAM address using PJL:
Our prototype implementation simply increments this value to dump the whole NVRAM, which contains passwords for the printer itself but also for user-defined POP3/SMTP as well as for FTP and Active Directory profiles. This way an attacker can escalate her way into a network, using the printer device as a starting point. Other attacks include:
File system access. Both, the standards for PostScript and PJL specify functionality to access the printers file system. As it seems, some manufacturers have not limited this feature to a certain directory, which leads to the disclosure of sensitive information like passwords.
Print job capture. If PostScript is used as a printer driver, printed documents can be captured. This is made possible by two interesting features of the PostScript language: First, permanently redefining operators allows an attacker to 'hook' into other users' print jobs and secondly, PostScript's capability to read its own code as data allows to easily store documents instead of executing them.
Credential disclosure. PJL passwords, if set, can easily retrieved through brute-force attacks due to their limited key space (1..65535). PostScript passwords, on the other hand, can be cracked extremely fast (up to 100,000 password verifications per second) thanks to the performant PostScript interpreters.
PRET
To automate the introduced attacks, we wrote a prototype software entitled PRET. The main idea of PRET is to facilitate the communication between the end-user and the printer. Thus, by entering a UNIX-like command PRET translates it to PostScript or PJL, sends it to the printer, and evaluates the result. For example, PRET converts a UNIX command ls to the following PJL request:
It then collects the printer output and translates it to a user friendly output.
PRET implements the following list of commands for file system access on a printer device:
Evaluation
As a highly motivated security researcher with a deep understanding of systematic analysis, you would probably obtain a list of about 20 - 30 well-used printers from the most important manufacturers, and perform an extensive security analysis using these printers. However, this was not our case. To overcome the financial obstacles, we collected printers from various university chairs and facilities. While our actual goal was to assemble a pool of printers containing at least one model for each of the top ten manufacturers, we practically took what we could get. The result is depicted in the following figure:
The assembled devices were not brand-new anymore and some of them were not even completely functional. Three printers had physically broken printing functionality so it was not possible to evaluate all the presented attacks. Nevertheless, these devices represent a good mix of printers used in a typical university or office environment.
Before performing the attacks, we of course installed the newest firmware on each of the devices. The results of our evaluation show that we could find multiple attacks against each printer. For example, simple DoS attacks with malicious PostScript files containing infinite loops are applicable to each printer. Only the HP LaserJet M2727nf had a watchdog mechanism and restarted itself after about ten minutes. Physical damage could be caused to about half of the tested device within 24 hours of NVRAM stressing. For a majority of devices, print jobs could be manipulated or captured.
PostScript, PJL and PML based attacks can even be exploited by a web attacker using advanced cross-site printing techniques. In the scope of our research, we discovered a novel approach – 'CORS spoofing' – to leak information like captured print jobs from a printer device given only a victim's browser as carrier. A proof-of-concept implementation demonstrating that advanced cross-site printing attacks are practical and a real-world threat to companies and institutions is available at http://hacking-printers.net/xsp/.
Our next post will be on adapting PostScript based attacks to websites.
The United States Cybersecurity and Infrastructure Security Agency (CISA) yesterday issued a fresh advisory alerting organizations to change all their Active Directory credentials as a defense against cyberattacks trying to leverage a known remote code execution (RCE) vulnerability in Pulse Secure VPN servers—even if they have already patched it. The warning comes three months after another
YardStick One Unleashed, Automating RF Attacks In Python - An RFCat Primer
I decided to dive into our current device a bit more before moving on to a new device, and really ramp up the skillsets with RFCat and the Yardstick.So for this blog you will need our previous Target and a Yardstick One. We will be hacking everyting using only the Yardstick and Python.
So last time we scanned for signals with GQRX and a Software Defined Radio device. We took the demodulated wave forms in Audacity and discerned what the binary representation of our wave forms were by decoding them manually. We then transferred those into a hex format that our yardstick understood.However there is a way to do everything with our Yardstick. It will require a bit more understanding of the RFCat library, and a bit of python.
This blog will be your RFCAT primer and coding tutorial, but don't be scared with the word "Programming" I will be using simple code, nothing complicated.So if your a programmer, tune out any coding explanation and understand RFCat, if your not a coder, then use this as a jumping point to start making some quick python scripts for hacking.
Video Series PlayList Associated with this blog:
The first thing we did in our last blog after looking up the frequency was to open up GQRX and check if we can see our devices signals. As it turns out you can actually do this in python with RFCat. Which is really convenient if you left your Software Defined Radio dongle at home but happen to have access to a Yardstick.
RFCat as a Spectrum Analyzer:
In order to use RFCat as a spectrum analyzer we need to make sure we have RFcat installed and a few prerequisites such as python and PySide modules.I actually did this inside of an Ubuntu VMware because Pyside was giving me issues on OSX and I didn't feel like trying to fix it. So If you spin up an ubuntu vm you can do the following to get things up and running..
Install Spectrum Analyzer PreReqs:
sudo pip install PySide
sudo apt-get install ipython
Plug in your adapter and type in the following:
rfcat -r
d.specan(315000000)
You will then see the below output of RFCat Specan running in the 315 MHz range.
Click our doorbell, or trip the motion sensor and you will see a frequency spike as shown in the second picture.
This is similar to what you saw in GQRX but all with your Yardstick and the Python RFCat library.
So everything seems to be working and we can see our devices transmitting on the 315MHz frequency.Unfortunately we have no record button on Spescan. This leaves us to dive a little deeper into RFCat. We will see what RFCat can do for us in the recording and sniffing capacity.
Sniffing RF Data With The YardStick and Python:
In RFCat there is a simple listening command in our interactive session which will give us an idea of what is being transmitted and in what type of data format we are recieving. When using GQRX we received a WAV file, but what does RFCat give us?One thing I have realized over the years is programming is all about dealing with data in various formats and figuring out how to parse and use it in various implementations. So the first thing we have to figure out is what kind of data we are dealing with.
Lets hop back into RFCat and set a few parameters so the yardstick knows to listen on 315MHz and to use ASK modulation.The settings below should all be familiar from our last blog with an exception of "lowball" which configures the radio to use the lowest level of filtering. We basically want to see everything but may experience some noise by not filtering it out.. For example before you hit your doorbell button you may see random FF FF FF FF data outputted to the screen.
Below is the cmdline input needed and some example output. After all of our settings are in place we can use RF.listen() to start listening for everything in the 315000000 frequency range and have it output to the screen.
After you set it up, you can press the button on your doorbell and you will receive the following output. We have lots of zeros and what might be some hex output.
Destroy ficti0n$rfcat -r
>>> d.setFreq(315000000)
>>> d.setMdmModulation(MOD_ASK_OOK)
>>> d.setMdmDRate(4800)
>>> d.setMaxPower()
>>> d.lowball()
>>> d.RFlisten()
Entering RFlisten mode...packets arriving will be displayed on the screen
If you hit "ENTER" in your terminal you will stop receiving packets and drop back into a python interactive terminal. If we take a look at the repeating pattern in the above output, it looks like some random patterns and then a repeating pattern of, 84e708421084e738.If we convert that to binary we can compare with what we decoded WAV from our previous blog.
Since we are already in a python terminal you can type the following to see the binary representation:
Lets break that up into 8 bit bytes and compare it to our previous blogs binary, hmm its lot different then what we originally decoded the signal to be:
If we take the above capture data and format it correctly for RFcat with the replay code from the last blog. When we send it over, it does indeed ring the doorbell, thats interesting. A completely different value in both hex and in binary and still we get a doorbell to ring. So the variance we talked about last time extends a bit more. Below is the code with the new hex from the capture data:
I will also take a minute to note something before we continue. I had a little trouble at first when using a telescopic antenna in RFcat and the YardStick.So I will list those issues below as notes for you to play with if you run into random looking captures when pressing your doorbell button.
When using a telescopic antenna closed I had almost repeating output with some random bits flipped
When extending the antenna it went crazy output with random noise
I then used a small rubber ducky antenna and got the repeating output shown above.
What we have done so far:
So above, we managed to figure out the following all in RFCat
Verify the frequency with RFCat
How can I listen for it and capture a transmission with RFCat
How can I send this transmission with RFCat
We have basically eliminated the immediate need for the graphical tools that we were using in the last blog. Not to say that they are not useful. They absolutely are, and we should use them often and know how to work with all kinds of formats and understand everything.. However, if we are living in a reality that all we have is a Yardstick and no other tools. We are not helpless and we can still kick some serious RF butt.
Now we are going to take this a bit further so we can learn some more about RFCat, Python and mistakesI made when trying to automate this stuff. I found some interesting quirks I had to work through and I would like to save others some time who are also in the learning process as I am.
Using RFrecv() for Listening:
Ok first thing I learned is that RFListen() is not all that useful when it comes to automating this stuff. I tried to set its output to a variable but that did not seem to work.. So instead we will be working with another feature that lets us listen and that is RFrecv().If we fire up our RFCat in the terminal again we can give that a try:
Destroy:~ ficti0n$ rfcat -r
>>> d.setFreq(315000000)
>>> d.setMdmModulation(MOD_ASK_OOK)
>>> d.setMdmDRate(4800)
>>> d.setMaxPower()
>>> d.lowball()
>>> d.RFrecv()
Traceback (most recent call last):
File "", line 1, in
File "/Library/Python/2.7/site-packages/rflib/chipcon_nic.py", line 1376, in RFrecv
data = self.recv(APP_NIC, NIC_RECV, timeout)
File "/Library/Python/2.7/site-packages/rflib/chipcon_usb.py", line 664, in recv
raise(ChipconUsbTimeoutException())
ChipconUsbTimeoutException: Timeout waiting for USB response.
OK thats not cool we are getting a weird error if we don't get a signal right away regarding ChipconUsbTimeoutException.
No problem since we are in a python terminal we can just capture this exception and pass it, then continue with sniffing.This is done with a Try/Except block.
try:
... d.RFrecv()
... except ChipconUsbTimeoutException:
... pass
...
That looks a little better, I am no longer receiving errors, but lets put this in a loop so we are continuously listening with RFrecv() and press our doorbell so we can capture our doorbell signal.Below is the output of a random signal that came in followed by our doorbell.. but its all kinds of crazy looking and a bit hard to read:
try:
... d.RFrecv()
... except ChipconUsbTimeoutException:
... pass
...
while True:
... try:
... d.RFrecv()
... except ChipconUsbTimeoutException:
... pass
Lets try to fix the output a little and make it more readable by encoding it before we view it. Open up your text editor and use the following code.What we are doing here is simply setting up our listener as we did before and then setting it to a variable we can use.
Line 12: Setting our RFrecv() output to the variable y and z. The y variable is the output that we want
Line 13: We will wrap the y variable with an encode function to encode it with a HEX encoding.
Line 14: After that we just print it out.
When we run this script from the command line we will get a much nicer output shown below, much like we did with the RFlisten function above. The big difference being that our data is now set to the variable "capture"on line 13 and we can do what we want with that data. For example we can directly replay that data rather then manually performing the actions.
Parsing and replaying data:
This actually took me a bit of time to figure out, so we need to do a few things to get this to work:
We need to parse out the data from the surrounding 0s
We need to convert it to a format we can send (tricker then it sounds)
We need to add padding and send that data over (We know how to do this already)
Parsing Data:
So with this I first tried all kinds of regular expressions, but for some reason the inverse of more then 3 zeros in a row does not seem to work. I am no regex master but that seemed like it should be working. I then tried a few creative solutions reducing repeating zeros down to pairs that I could split on with string functions. This actually worked well but then my buddy showed me this which was more efficient:
re.split ('0000*', capture)
All this is doing is using the regex library to parse on a set of 4 or more zerosand return whats left in a list of useable hex data for sending.So lets add that into our code and give it a try to see what we get back. I made the following code changes:
Line 2: Import the Regex library
Line 11: We defined the capture variable so we can access it outside of the Try Block and the loop
Line 21: We created a payloads variable and created a list from the capture file of non 0000 blocks
Line 22: We print out our list of useable payloads which can been seen in the below output
Data Format Woes:
So we have data in a list we can pull from, thats awesome but I ran into a few issues. I first tried to parse this data into the \x format we normally used when sending our attack payloads manually, but that actually does not work. Reason being that if I use a code snippet like the following to convert this data into the right format everything looks ok and something like this \x84\xe7\x08\x42\x10\x84\xe7.But it won't actually work when I send it with RFCat. For some reason when you paste in your own hex its in a different format then if you programmatically create hex like below. You don't really need to understand the code below, just know it takes our payload and creates the hex in a visual format to what we used in the last blog:
DON'T USE THIS.. IT WONT WORK!!!
for payload in payloads:
formatted = ""
if (len(payload) > 6) and (len(payload) % 2 == 0):
print "Currently being formatted: " + payload
iterator = iter(payload)
for i in iterator:
formatted += ('\\x'+i + next(iterator))
else:
continue
Formatted Hex Vs Manually Pasted Hex
So lets compare the outputs of our manually created Hex String versus what we get when we format with the above code
Below is the output of the following:
Your encoded capture
Your parsed payloads in a nice list
Your payload being processed into hex.
But this is where things go wrong, you then have :
Your nicely formatted Hex created by your code above (Yay for us)
Then you have your manually pasted in hex from your original attack payloads as unprintable characters(What?)
You can clearly see there is a major difference between when we manually paste in our hex like we did in the last blog and when we create it from our capture file.This led to another sleepless night of researching whats going on. I did a bunch of troubleshooting until I found some code on the RFcat site and saw it using the BitString library and something called BitArray.The examples for this library were using binary data instead of hex and then converting it.
BitString BitArray Formating FTW:
If you remember above we created binary input with some python, so lets use that code in our current program template and then feed it into byteArray and see what happens. We can install bitstring with the following:
Install Bitstring:
sudo pip install bitstring
Our New code using BitString:
Line 2: I imported bitstring
Line 25: I added a for loop to go through our payload list one by one
Line 27: I convert our current payload to binary
Line 28: I take that binary and I feed it into bitstring to fix the formatting issues
Lines 29-30:Print out our binary and our new data that match our manually pasted data format, shown below
With these conversions the data above looks like its correct to attack our target devices. I know this seems like a lot of steps, but honestly this is only 50 lines of code in all to automate our replay attacks in a simple way.It is also very easy if you know what your doing and don't spend all of your time figuring it out like I did. You just need to understand how to work with the types of data each component understands.
With this latest code update we are ready to send our code with a simple modification to our RFxmit line from the last blog. We will now change RXxmit to take our formatted variable and then append our padding:
Below is our full code to automate this attack, with a few changeups, but not many.. Really all I did was add some conditional statements to limit our data to longer payloads that are divisible by 2 since our hex takes 2 string characters for example \x41 is the string character 4 and 1.I originally did this for the iterator code which required the proper amount of characters but decided to leave it since it makes sense anyway.I also set it so that if there is a capture it breaks out of the loop. This way we are not continuously attacking every transmission we see. Instead for our testing we can hit our doorbell, replay all the values before our script finishes and exits.
Note: I sent similar code to a friend and had him run it against a black box real world target. He had permission to attack this target via the owner of a facility and it worked flawlessly. So although a doorbell is a trivial target. This same research applies to garages, gates, and any other signal not using protection mechanism such as rolling code, multiple frequencies at once etc.
Also note that when you run this, almost all of the payloads in your list will ring the doorbell which is why I put a timing variable before the sending command. This way your doorbell isn't overburdened. I already broke a few of these devices during testing LOL.
I have since modified this code to be more effective, and have additional features and more niceties, I will release that code when its ready.. For now enjoy the below code and hit me up with any questions or comments.
I hope this blog is helpful in demystifying RFCat in order to successfully perform/automate attacks with only Python and your Yardstick One. This is essentially a few nights of my research posted here for everyone to learn from. Because it was a pain to find useful information, and I would like to save other people a lot of sleepless nights. I am by no means the master of RF or RFCat, there is tons more to learn. Up next I will get back on track with a real world attack against a device and creating our own keyfobs to replay our attacks in the future.
