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In this post we will show why Gridcoin is insecure and probably will never achieve better security. Therefore, we are going to explain two critical implementation vulnerabilities and our experience with the core developer in the process of the responsible disclosure. 

1. We can steal the block creation reward from many Gridcoin minters
2. We can efficiently prevent many Gridcoin minters from claiming their block creation reward (DoS attack)

So why do we not just open up an issue online explaining the problems?

Because we already fixed a critical design issue in Gridcoin last year and tried to help them to fix the new issues. Unfortunately, they do not seem to have an interest in securing Gridcoin and thus leave us no other choice than fully disclosing the findings.

In order to explain the vulnerabilities we will take a look at the current Gridcoin source code (version 3.5.9.8).

WARNING: Due to the high number of source code lines in the source files, it can take a while until your browser shows the right line.

Stealing the BOINC block reward

The developer implemented our countermeasures in order to prevent our attack from the last blog post. Unfortunately, they did not look at their implementation from an attacker's perspective. Otherwise, they would have found out that they conduct not check, if the signature over the last block hash really is done over the last block hash. But we come to that in a minute. First lets take a look at the code flow:

In the figure the called-by-graph can be seen for the function VerifyCPIDSignature.

1. CheckBlock → DeserializeBoincBlock [Source]
• Here we deserialize the BOINC data structure from the first transaction
2. CheckBlock → IsCPIDValidv2 [Source]
• Then we call a function to verify the CPID used in the block. Due to the massive changes over the last years, there are 3 possible verify functions. We are interested in the last one (VerifyCPIDSignature), for the reason that it is the current verification function.
3. IsCPIDValidv2 → VerifyCPIDSignature [Source]
4. VerifyCPIDSignature → CheckMessageSignature [Source, Source]

If we go backwards in the function call graph we see that in VerifyCPIDSignature the sMsg is the string sConcatMessage, which is a concatenation of the sCPID and the sBlockHash.
We are interested where the sBlockHash value comes from, due to the fact that this one is the only changing value in the signature generation.
When we go backwards, we see that the value originate from the deserialization of the BOINC structure (MiningCPID& mc) and is the variable mc.lastblockhash [Source, Source]. But wait a second, is this value ever checked whether it contains the real last block hash?

No, it is not....

So they just look if the stored values there end up in a valid signature.

Thus, we just need to wait for one valid block from a researcher and copy the signature, the last block hash value, the CPID and adjust every other dynamic value, like the RAC. Consequently, we are able to claim the reward of other BOINC users. This simple bug allows us again to steal the reward of every Gridcoin researcher, like there was never a countermeasure.

Lock out Gridcoin researcher
The following vulnerability allows an attacker under specific circumstances to register a key pair for a CPID, even if the CPID was previously tied to another key pair. Thus, the attacker locks out a legit researcher and prevent him from claiming BOINC reward in his minted blocks.

Reminder: A beacon is valid for 5 months, afterwards a new beacon must be sent with the same public key and CPID.

Therefore, we need to take a look at the functions, which process the beacon information. Every time there is a block, which contains beacon information, it is processed the following way (click image for higher resolution):

In the figure the called-by-graph can be seen for the function GetBeaconPublicKey.

We now show the source code path:

• ProcessBlock → CheckBlock [Source]
• CheckBlock → LoadAdminMessages [Source]
• LoadAdminMessages → MemorizeMessages [Source]
• MemorizeMessages → GetBeaconPublicKey [Source]

In the last function GetBeaconPublicKey there are different paths to process a beacon depending on the public key, the CPID, and the time since both were associated to each other.
For the following explanation we assume that we have an existing association (bound) between a CPID A and a public key pubK_A for 4 months.

1. First public key for a CPID received [Source]
• The initial situation, when pubK_A was sent and bind to CPID  A (4 months ago)
2. Existing public key for a CPID was sent [Source]
• The case that pubK_A was resent for a CPID A, before the 5 months are passed by
3. Other public key for a CPID was sent [Source]
• The case, if a different public key pubK_B for the CPID A was sent via beacon.
4. The existing public key for the CPID is expired
• After 5 months a refresh for the association between A and pubK_A is required.

The responsible disclosure process

As part of our work as researchers we all have had the pleasure to responsible disclose the findings to developer or companies.

For the reasons that we wanted to give the developer some time to fix the design vulnerabilities, described in the last blog post, we did not issue a ticket at the Gridcoin Github project. Instead we contacted the developer at September the 14th 2016 via email and got a response one day later (2016/09/15). They proposed a variation of our countermeasure and dropped the signature in the advertising beacon, which would result in further security issues. We sent another email (2016/09/15) explained to them, why it is not wise to change our countermeasures and drop the signature in the advertising beacon.
Unfortunately, we did not receive a response. We tried it again on October the 31th 2016. They again did not respond, but we saw in the source code that they made some promising changes. Due to some other projects we did not look into the code until May 2017. At this point we found the two implementation vulnerabilities. We contacted the developer twice via email (5th and 16th of May 2017) again, but never received a response. Thus, we decided to wait for the WOOT notification to pass by and then fully disclose the findings. We thus have no other choice then to say that:

The whole Gridcoin cryptocurrency is seriously insecure against attacks and should not be trusted anymore; unless some developers are in place, which have a profound background in protocol and application security.

A more detailed description of the Gridcoin architecture, the old design issue and the fix will be presented at WOOT'17. Some days after the conference the paper will be available online.

A keylogger is a computer program which can be written using any computer programming language such as c++ when you install it on a Victim system it can keep the records of every keystroke in a text file. Keylogger is mainly used to steal confidential data such as passwords, credit card numbers etc.

A keylogger can be programmed using any programming language such as c++, java, c# e.tc. For this tutorial, I will use python to make a keylogger, because python is flexible, powerful and simple to understand even a non-programmer can use python to make a keylogger.

Requirements to create a python keylogger

You will learn to install these things one by one. If you have already installed and configured the python development kit feel free to skip Part 1.

Download python development kit by clicking here.

Choose python 2.7 because I am using this version. It is ok if you have a different version of python this method will work on every version of python.

Installation of python is pretty simple.Open the python setup file, Mark the checkboxes Very important else you have to set the python path manually, and click on Install Now.

You need Pypiwin32 and PyHook python packages to create python keylogger. To install these packages you need pip, you can install Pypiwin32 and PyHook without using pip which is not recommended.

To download pip go to https://pip.pypa.io/en/stable/installing/ and Save link as by right clicking on get-pip.py. when the download is done, just run the get-pip.py file.

Now you need to set the Variable path for pip to do this right click on the computer icon and choose properties.

Now click on the Advanced system settings

Choose Environment Variables.

Choose New, Set the Variable name: PATH and Variable value as C:\Python27\Scripts

Click on ok.

Open Command Prompt(CMD) and type: pip installs Pypiwin32 press the Enter Key, wait for the installation to complete. After the Pypiwin32 package installation type: pip install PyHook press the Enter Key and wait for the installation to complete.When done close the Command Prompt.

Now you have configured your environment and installed all the necessary packages, let's start creating the keylogger. Click on the start menu and scroll down until you find Python 2.7, run python IDLE(GUI) by clicking on it.

Go to the File, from the drop-down menu choose New file.

Copy these lines of code and paste into the new file. Modify the directory in the second line of code to your own location e.g 'C:\test\log.txt' this will create a folder named test in C save the log.txt file there when the Keylogger start.

Save your file as a test.pyw at any location you want, the .pyw extension is very important because of it the python keylogger will run in the background without notifying the user.

The Python Keylogger is now completed you can test it out by opening it and typing some text in your browser, go to the log.txt file which is in the F:\test\log.txt on my PC. You will find your log.txt file in C:\test\log.txt.But what if you want to test it on someone else computer? you want to run it without the user knowing that it has been launched, this can be done by attaching it to the program that the victim always uses such as Google Chrome.

Copy the following code and paste into notepad. Save it by giving .bat extension e.g launch.bat in a hidden location, e.g c:\test\launch.bat

Now right click on the google chrome desktop shortcut icon and click on properties. You will see a field called Target. Change the target field to the batch file launch.bat directory that you created. let's say you have saved your launch.bat file in a test folder in C, Then change the target field with "C:\test\launch.bat". Now, whenever the user opens chrome the keylogger will run automatically.