Electronic Campaingn Application Forum

Opey

Smart Contract Exploitation and Hacking Course Announcement

What Is this:

For those who have been hitting me up on twitter and YouTube for more blockchain smart contract exploitation content this blog is for you. I have posted a video below explaining what this is and included a course outline of the content we are providing free for everyone. I was actually told recently that I am crazy for giving out this level of detailed content and training for free.. However, I believe in the original hacker ethic code from long ago, that information should be freely available for everyone!! In this frame of mind, the only pay for content will be if you wish to go the extra mile. For the person who wants to prove to themselves or others that they learned something via a certification package with detailed exam prep targets and guides, followed by a final exam CTF and reporting write-up.

So I hope you enjoy this content. The content and walk through labs will be all free. This content will be posted regularly over the next few months 90% of it is already written and ready to go.

We will start off with the differences between Solidity and other languages and do a quick coding overview before we start hacking. This way everyone is on the same page when we start looking at coding examples of vulnerable targets or reviewing case study code. Then we will cover a wide range of typical issues that effect decentralized applications(DApps) and smart contracts on the Ethereum blockchain. How to spot them and exploit them with full walk-through style learning. Subjects we have already released (Re-Entrancy, Integer Attacks, Authorization) have been updated with new code, new examples, and case studies etc. Some of the learning content will be the same but with a lot of newly added content. And in the case of Authorization completely re-written and expanded on.

Basically this course was created to get the information out there in a clear concise way. Because when I started researching blockchain hacking all I found was a paragraph here and there on something that was overly technical or completely theoretical. I couldn't find any clear concise learning or examples. This drove me nuts trying to figure everything out, until I gave up and just coded my own vulnerabilities and hacked them. So hopefully this fills the knowledge gap to offer a clear and concise, Zero Fluff resource to those on the same path.

CTF Exam:

If you do enjoy this series over the next few months and want to challenge your skills and certify that you learned something we will be also offering pay for certification bundle that includes Decentralized Application (DApp) targets and detailed lab guides as preparation for a final exam against a more comprehensive CTF certification challenge target. More info on this as the months progress.

Bug Bounty of Sorts:

These labs are completed but we are working on a way to deliver the content which requires me to code up a course delivery software. So feel free to hack the course delivery software once its up, if you break in or bypass authorizations I will give you the full course for free provided you help me fix it. :P

Pre- Requisites:

This is more of a intermediate / advanced course with a white box code approach to bug hunting and a dynamic approach to application hacking and exploiting targets, with that said you will need the following pre-requisites:

Ability to code in some language and understanding of coding concepts.
Application hacking or development background with firm understanding of vulnerabilities

Contact Info:

As this is free, I only ask that you provide constructive feedback as we are creating other more advanced hacking courses on random subjects we are interested in. Most of which will be free. And feedback helps us not do things which are not useful and integrate new ideas where they make sense.

Cheers and I hope this finds you well.

Twitter:

Email:

info@cclabs.io

WebPage:

Intro Video:

Course Outline / Release Order:

Orange = = Whats included additionally for the full course

Blue = = What will be released free in blogs / videos

(Mostly every Mondays) over the next few months

Building and Scoping Things

Chapter 1: Cliff Notes on Blockchain

Intro:

What is a Blockchain and how is it secured

Smart Contracts

What is a Decentralized Application (DApp)?

Diving into Blockchain Components:

Distributed Vs Decentralized

Provenance Use Case:

Consensus and Mining:

Hands on Lab - Blockchain Consensus walkthrough Lab

Summary:

References:

Chapter 2: Threat Modeling and Scoping Engagements

Architecture Considerations:

Business Logic Locations and Technology Decisions

Development Environments

Threat Modeling

Summary

References:

Chapter 3 – Solidity for Penetration Testers Part 1 (Hello World)

About Solidity

Hands on Lab - Remix interface overview

Structure of a Smart Contract

Hands on Lab – HelloWorld

Summary

References:

Chapter 4 – Solidity for Penetration Testers Part 2

Beyond Hello World

Hands on Lab – Code HelloWorld bank

Code Level Walk Through of HelloWorld Bank

Checks Effects Interactions:

Summary

Part 2: Hacking and Exploiting Things

Chapter 5 - Glass Half Full or Glass Half Empty: Integer Attacks

Underflows and Overflows

Withdraw Function Vulnerable to an underflow

Transfer Function Vulnerable to a Batch Overflow

Batch Overflow Code Explanation:

ERC20 Batch Overflow Case-Study

Walkthrough of The Vulnerable Function

Reviewing the Real Attack Transaction

Hands on Lab - Exploiting Our Own ERC20 Batch Overflow

Hands on Lab - Fixing the ERC20 Overflow

Exam Prep - DApp Target + Detailed Lab Guide

Hands on Lab -Safe Math Walk Through

Integer Attacks Summary

Integer Attacks References

Chapter 6 - You Again: Leveraging Reentrancy Attacks

Reentrancy Intro

Checks Effects Interactions Pattern

Simple Reentrancy Example Code

Passing the Checks:

Looping the Interaction:

Updating the Effects:

Attacking Code Example:

Hands on Lab - Attacking a Simple Reentrancy

Hands on Lab - Fixing the Checks Effects interaction Pattern

Send vs Transfer Vs Call.Value

Case Study – The Dao Hack

Exam Prep - DApp Target + Detailed Lab Guide

Reentrancy Summary

Reentrancy References

Chapter 7 Do You Have a Hall Pass: Access Control Attacks

Understanding Smart Contract Authorization and Visibility

Visibility:

Simple Visibility Example:

Implementing Authorization:

Example Walk-through of No Authorization

Thinking about Smart Contracts as unpublished API's for DApps

Case of the Video Game Heist

Enumerating functions in a contract

Hands on Lab - Directly Calling Public Functions with Web3

Hands on Lab - Example Fix with Simple Authorization

Exit Scam Warning

Hands on Lab - Example Fix-2 Using Modifiers for Simple Authentication

Hands on Lab - Example Using Openzeppelin for Role Based Access Control

Exam Prep - DApp Target + Detailed Lab Guide

Authorization Summary:

Authorization References

Chapter 8 - Dude Where's My Data: Storage Vs Memory Attacks

Intro - Not Written Yet – Up Next

Code Example - Not Written Yet – Up Next

Case study? - Not Written Yet – Up Next

Exploiting vulnerability - Not Written Yet – Up Next

Summary - Not Written Yet – Up Next

References - Not Written Yet – Up Next

Chapter 9 - Do I know you: TxOrigin vs Message.sender Attacks

What's the difference?

Man In the Middle Via tx.origin

Hands on Lab - Simple tx.origin Example Walkthrough

Hands on Lab - Vulnerable TX.Origin Example Walkthrough

Exam Prep - DApp Target + Detailed Lab Guide

Action steps to familiarize yourself with the contract:

Attack Options:

Summary

References

Chapter 10 - Who Am I: Delegate Call Attacks

How delegate calls work:

Delegate Call vs Call

Simple Delegate Call Example Code

Simple Delegate Code Example Walkthrough

Hands on Lab - Simple Delegate Example Walkthrough

Variable Memory Issues with Delegate Calls

DelegateCall Storage Simple Example Code

Hands on Lab - DelegateCall Storage Walkthrough

Exam Prep - DApp Target + Detailed Lab Guide

Case Study - Parity Wallet Attack:

Attack Transactions Explained

Dangerous fallback function using delegatecall

The Parity Wallet Code

Delegate Chapter Summary

Delegate References:

Chapter 11 - Look into My Crystal Ball: Bad Randomness Issues

Cryptographic Implementations and Predictable PRNGs

Simple BlockHash Example

Hands on Lab - BlockHash Vulnerability Walk and Talk

Exam Prep - DApp Target + Detailed Lab Guide

Preventing Randomness Issues

Bad Randomness Summary

Bad Randomness References

Chapter 12 - Automated Static Application Security Testing

Content - Not written - Up Next

Hands On Lab - Not written - Up Next

Summary Not written - Up Next

References - Not written - Up Next

Chapter 13 - CTF Exam

Final Exam and CTF Certification Exam Target

Final Exam Reporting

Appendices:

Appendix I – Pre-Requisite Suggestions:

Programming Pre-Requisites:

Web Application Hacking Pre-Requisites:

Appendix II – Other Blockchain Learning Resources and Certifications

Appendix III – Non-Exhaustive Scoping Questions

Appendix IV – Non-Exhaustive List of things to check for

Related links

Opey

In this article we are going to do the SQL Injection (Blind) challenge of DVWA.
OWASP describes Blind SQL Injection as:
"Blind SQL (Structured Query Language) injection is a type of attack that asks the database true or false questions and determines the answer based on the applications response. This attack is often used when the web application is configured to show generic error messages, but has not mitigated the code that is vulnerable to SQL injection.

When an attacker exploits SQL injection, sometimes the web application displays error messages from the database complaining that the SQL Query's syntax is incorrect. Blind SQL injection is nearly identical to normal , the only difference being the way the data is retrieved from the database. When the database does not output data to the web page, an attacker is forced to steal data by asking the database a series of true or false questions. This makes exploiting the SQL Injection vulnerability more difficult, but not impossible."

To follow along click on the SQL Injection (Blind) navigation link. You will be presented with a page like this:

Lets first try to enter a valid User ID to see what the response looks like. Enter 1 in the User ID field and click submit. The result should look like this:

Lets call this response as valid response for the ease of reference in the rest of the article. Now lets try to enter an invalid ID to see what the response for that would be. Enter something like 1337 the response would be like this:

We will call this invalid response. Since we know both the valid and invalid response, lets try to attack the app now. We will again start with a single quote (') and see the response. The response we got back is the one which we saw when we entered the wrong User ID. This indicates that our query is either invalid or incomplete. Lets try to add an or statement to our query like this:

' or 1=1-- -

This returns a valid response. Which means our query is complete and executes without errors. Lets try to figure out the size of the query output columns like we did with the sql injection before in Learning Web Pentesting With DVWA Part 2: SQL Injection.
Enter the following in the User ID field:

' or 1=1 order by 1-- -

Again we get a valid response lets increase the number to 2.

' or 1=1 order by 2-- -

We get a valid response again lets go for 3.

' or 1=1 order by 3-- -

We get an invalid response so that confirms the size of query columns (number of columns queried by the server SQL statement) is 2.
Lets try to get some data using the blind sql injection, starting by trying to figure out the version of dbms used by the server like this:

1' and substring(version(), 1,1) = 1-- -

Since we don't see any output we have to extract data character by character. Here we are trying to guess the first character of the string returned by version() function which in my case is 1. You'll notice the output returns a valid response when we enter the query above in the input field.
Lets examine the query a bit to further understand what we are trying to accomplish. We know 1 is the valid user id and it returns a valid response, we append it to the query. Following 1, we use a single quote to end the check string. After the single quote we start to build our own query with the and conditional statement which states that the answer is true if and only if both conditions are true. Since the user id 1 exists we know the first condition of the statement is true. In the second condition, we extract first character from the version() function using the substring() function and compare it with the value of 1 and then comment out the rest of server query. Since first condition is true, if the second condition is true as well we will get a valid response back otherwise we will get an invalid response. Since my the version of mariadb installed by the docker container starts with a 1 we will get a valid response. Lets see if we will get an invalid response if we compare the first character of the string returned by the version() function to 2 like this:

1' and substring(version(),1,1) = 2-- -

And we get the invalid response. To determine the second character of the string returned by the version() function, we will write our query like this:
1' and substring(version(),2,2) = 1-- -
We get invalid response. Changing 1 to 2 then 3 and so on we get invalid response back, then we try 0 and we get a valid response back indicating the second character in the string returned by the version() function is 0. Thus we have got so for 10 as the first two characters of the database version. We can try to get the third and fourth characters of the string but as you can guess it will be time consuming. So its time to automate the boring stuff. We can automate this process in two ways. One is to use our awesome programming skills to write a program that will automate this whole thing. Another way is not to reinvent the wheel and try sqlmap. I am going to show you how to use sqlmap but you can try the first method as well, as an exercise.
Lets use sqlmap to get data from the database. Enter 1 in the User ID field and click submit.
Then copy the URL from the URL bar which should look something like this
http://localhost:9000/vulnerabilities/sqli_blind/?id=1&Submit=Submit
Now open a terminal and type this command:

sqlmap --version

this will print the version of your sqlmap installation otherwise it will give an error indicating the package is not installed on your computer. If its not installed then go ahead and install it.
Now type the following command to get the names of the databases:

sqlmap -u "http://localhost:9000/vulnerabilities/sqli_blind/?id=1&Submit=Submit" --cookie="security=low; PHPSESSID=aks68qncbmtnd59q3ue7bmam30" -p id

Here replace the PHPSESSID with your session id which you can get by right clicking on the page and then clicking inspect in your browser (Firefox here). Then click on storage tab and expand cookie to get your PHPSESSID. Also your port for dvwa web app can be different so replace the URL with yours.
The command above uses -u to specify the url to be attacked, --cookie flag specifies the user authentication cookies, and -p is used to specify the parameter of the URL that we are going to attack.
We will now dump the tables of dvwa database using sqlmap like this:

sqlmap -u "http://localhost:9000/vulnerabilities/sqli_blind/?id=1&Submit=Submit" --cookie="security=low; PHPSESSID=aks68qncbmtnd59q3ue7bmam30" -p id -D dvwa --tables

After getting the list of tables its time to dump the columns of users table like this:

sqlmap -u "http://localhost:9000/vulnerabilities/sqli_blind/?id=1&Submit=Submit" --cookie="security=low; PHPSESSID=aks68qncbmtnd59q3ue7bmam30" -p id -D dvwa -T users --columns

And at last we will dump the passwords column of the users table like this:

sqlmap -u "http://localhost:9000/vulnerabilities/sqli_blind/?id=1&Submit=Submit" --cookie="security=low; PHPSESSID=aks68qncbmtnd59q3ue7bmam30" -p id -D dvwa -T users -C password --dump

Now you can see the password hashes.
As you can see automating this blind sqli using sqlmap made it simple. It would have taken us a lot of time to do this stuff manually. That's why in pentests both manual and automated testing is necessary. But its not a good idea to rely on just one of the two rather we should leverage power of both testing types to both understand and exploit the vulnerability.
By the way we could have used something like this to dump all databases and tables using this sqlmap command:

sqlmap -u "http://localhost:9000/vulnerabilities/sqli_blind/?id=1&Submit=Submit" --cookie="security=low; PHPSESSID=aks68qncbmtnd59q3ue7bmam30" -p id --dump-all

But obviously it is time and resource consuming so we only extracted what was interested to us rather than dumping all the stuff.
Also we could have used sqlmap in the simple sql injection that we did in the previous article. As an exercise redo the SQL Injection challenge using sqlmap.

References:

1. Blind SQL Injection: https://owasp.org/www-community/attacks/Blind_SQL_Injection
2. sqlmap: http://sqlmap.org/
3. MySQL SUBSTRING() Function: https://www.w3schools.com/sql/func_mysql_substring.asp

ps

The "ps" command is used in Linux to display your currently active processes over the Linux based system. It will give you all the detail of the processes which are active on the system.

ps aux|grep

The "ps aux|grep" command is used in Linux distributions to find all the process id of particular process like if you wanna know about all the process ids related to telnet process then you just have to type a simple command like "ps aux|grep 'telnet'". This command will give you the details about telnet processes.

pmap

The "pmap" command in Linux operating system will display the map of processes running over the memory in Linux based system.

top

The "top" command is used in Linux operating system to display all the running processes over the system's background. It will display all the processes with process id (pid) by which you can easily kill/end the process.

Kill pid

Basically the kill command is used to kill or end the process or processes by simply giving the process id to the kill command and it will end the process or processes. Just type kill and gave the particular process id or different process ids by putting the space in between all of them. kill 456 567 5673 etc.

killall proc

The "killall proc" is the command used in Linux operating system to kill all the processes named proc in the system. Killall command just require a parameter as name which is common in some of the processes in the system.

bg

The "bg" is the command used in Linux distributions to resume suspended jobs without bringing them to foreground.

fg

The "fg" command is used in Linux operating system to brings the most recent job to foreground. The fg command also requires parameters to do some actions like "fg n" n is as a parameter to fg command that brings job n to the foreground.More info

Electronic Campaingn Application Forum

Sunday, 30 August 2020

Blockchain Decentralized Application Hacking Course - A Journey Into Smart Contract Hacking And DApp Penetration Testing (Web 3.0)

Smart Contract Exploitation and Hacking Course Announcement

What Is this:

CTF Exam:

Bug Bounty of Sorts:

Pre- Requisites:

Contact Info:

Intro Video:

Course Outline / Release Order:

Orange = = Whats included additionally for the full course

Blue = = What will be released free in blogs / videos

(Mostly every Mondays) over the next few months

Related links

Learning Web Pentesting With DVWA Part 3: Blind SQL Injection

References:

Read more

Top Process Related Commands In Linux Distributions

ps

ps aux|grep

pmap

top

Kill pid

killall proc

bg

fg