Hacked Gadgets: A resource for DIY project documentation as well as general gadget and technology news.
The Hacker News: The Hacker News — most trusted and widely-acknowledged online cyber security news magazine with in-depth technical coverage for cybersecurity.
Hakin9: E-magazine offering in-depth looks at both attack and defense techniques and concentrates on difficult technical issues.
Packet Storm: Information Security Services, News, Files, Tools, Exploits, Advisories and Whitepapers.
KitPloit: Leading source of Security Tools, Hacking Tools, CyberSecurity and Network Security.
HackRead: HackRead is a News Platform that centers on InfoSec, Cyber Crime, Privacy, Surveillance, and Hacking News with full-scale reviews on Social Media Platforms.
Exploit DB: An archive of exploits and vulnerable software by Offensive Security. The site collects exploits from submissions and mailing lists and concentrates them in a single database.
SecTools.Org: List of 75 security tools based on a 2003 vote by hackers.
Metasploit: Find security issues, verify vulnerability mitigations & manage security assessments with Metasploit. Get the worlds best penetration testing software now.
Are you tired of reading endless news stories about ethical hacking and not really knowing what that means? Let's change that!
This Post is for the people that:
Have No Experience With Cybersecurity (Ethical Hacking)
Have Limited Experience.
Those That Just Can't Get A Break
OK, let's dive into the post and suggest some ways that you can get ahead in Cybersecurity.
I receive many messages on how to become a hacker. "I'm a beginner in hacking, how should I start?" or "I want to be able to hack my friend's Facebook account" are some of the more frequent queries. Hacking is a skill. And you must remember that if you want to learn hacking solely for the fun of hacking into your friend's Facebook account or email, things will not work out for you. You should decide to learn hacking because of your fascination for technology and your desire to be an expert in computer systems. Its time to change the color of your hat 😀
I've had my good share of Hats. Black, white or sometimes a blackish shade of grey. The darker it gets, the more fun you have.
If you have no experience don't worry. We ALL had to start somewhere, and we ALL needed help to get where we are today. No one is an island and no one is born with all the necessary skills. Period.OK, so you have zero experience and limited skills…my advice in this instance is that you teach yourself some absolute fundamentals.
Let's get this party started.
What is hacking?
Hacking is identifying weakness and vulnerabilities of some system and gaining access with it.
Hacker gets unauthorized access by targeting system while ethical hacker have an official permission in a lawful and legitimate manner to assess the security posture of a target system(s)
There's some types of hackers, a bit of "terminology". White hat — ethical hacker. Black hat — classical hacker, get unauthorized access. Grey hat — person who gets unauthorized access but reveals the weaknesses to the company. Script kiddie — person with no technical skills just used pre-made tools. Hacktivist — person who hacks for some idea and leaves some messages. For example strike against copyright.
In this blog series we will analyze blockchain vulnerabilities and exploit them ourselves in various lab and development environments. If you would like to stay up to date on new posts follow and subscribe to the following: Twitter: @ficti0n
As of late I have been un-naturally obsessed with blockchains and crypto currency. With that obsession comes the normal curiosity of "How do I hack this and steal all the monies?"
However, as usual I could not find any actual walk thorough or solid examples of actually exploiting real code live. Just theory and half way explained examples.
That question with labs is exactly what we are going to cover in this series, starting with the topic title above of Re-Entrancy attacks which allow an attacker to siphon out all of the money held within a smart contract, far beyond that of their own contribution to the contract.
This will be a lab based series and I will show you how to use demo the code within various test environments and local environments in order to perform and re-create each attacks for yourself.
Note: As usual this is live ongoing research and info will be released as it is coded and exploited.
If you are bored of reading already and just want to watch videos for this info or are only here for the demos and labs check out the first set of videos in the series at the link below and skip to the relevant parts for you, otherwise lets get into it:
Background Info:
This is a bit of a harder topic to write about considering most of my audience are hackers not Ethereum developers or blockchain architects. So you may not know what a smart contract is nor how it is situated within the blockchain development model. So I am going to cover a little bit of context to help with understanding.I will cover the bare minimum needed as an attacker.
A Standard Application Model:
In client server we generally have the following:
Front End - what the user sees (HTML Etc)
Server Side - code that handles business logic
Back End - Your database for example MySQL
A Decentralized Application Model:
Now with a Decentralized applications (DAPP) on the blockchain you have similar front end server side technology however
Smart contracts are your access into the blockchain.
Your smart contract is kind of like an API
Essentially DAPPs are Ethereum enabled applications using smart contracts as an API to the blockchain data ledger
DAPPs can be banking applications, wallets, video games etc.
A blockchain is a trust-less peer to peer decentralized database or ledger
The back-end is distributed across thousands of nodes in its entirety on each node. Meaning every single node has a Full "database" of information called a ledger.The second difference is that this ledger is immutable, meaning once data goes in, data cannot be changed. This will come into play later in this discussion about smart contracts.
Consensus:
The blockchain of these decentralized ledgers is synchronized by a consensus mechanism you may be familiar with called "mining" or more accurately, proof of work or optionally Proof of stake.
Proof of stake is simply staking large sums of coins which are at risk of loss if one were to perform a malicious action while helping to perform consensus of data.
Much like proof of stake, proof of work(mining) validates hashing calculations to come to a consensus but instead of loss of coins there is a loss of energy, which costs money, without reward if malicious actions were to take place.
Each block contains transactions from the transaction pool combined with a nonce that meets the difficulty requirements.Once a block is found and accepted it places them on the blockchain in which more then half of the network must reach a consensus on.
The point is that no central authority controls the nodes or can shut them down. Instead there is consensus from all nodes using either proof of work or proof of stake. They are spread across the whole world leaving a single centralized jurisdiction as an impossibility.
Things to Note:
First Note: Immutability
So, the thing to note is that our smart contracts are located on the blockchain
And the blockchain is immutable
This means an Agile development model is not going to work once a contract is deployed.
This means that updates to contracts is next to impossible
All you can really do is createa kill-switch or fail safe functions to disable and execute some actions if something goes wrong before going permanently dormant.
If you don't include a kill switch the contract is open and available and you can't remove it
Second Note:Code Is Open Source
Smart Contracts are generally open source
Which means people like ourselves are manually bug hunting smart contracts and running static analysis tools against smart contract code looking for bugs.
When issues are found the only course of action is:
Kill the current contract which stays on the blockchain
Then deploy a whole new version.
If there is no killSwitch the contract will be available forever.
Now I know what you're thinking, these things are ripe for exploitation.
And you would be correct based on the 3rd note
Third Note: Security in the development process is lacking
Many contracts and projects do not even think about and SDLC.
They rarely add penetration testing and vulnerability testing in the development stages if at all
At best there is a bug bounty before the release of their main-nets
Which usually get hacked to hell and delayed because of it.
Things are getting better but they are still behind the curve, as the technology is new and blockchain mostly developers and marketers.Not hackers or security testers.
Forth Note:Potential Data Exposure via Future Broken Crypto
If sensitive data is placed on the blockchain it is there forever
Which means that if a cryptographic algorithm is broken anything which is encrypted with that algorithm is now accessible
We all know that algorithms are eventually broken!
So its always advisable to keep sensitive data hashed for integrity on the blockchain but not actually stored on the blockchain directly
Exploitation of Re-Entrancy Vulnerabilities:
With a bit of the background out of the way let's get into the first attack in this series.
Re-Entrancy attacks allow an attacker to create a re-cursive loop within a contract by having the contract call the target function rather than a single request from auser. Instead the request comes from the attackers contract which does not let the target contracts execution complete until the tasks intended by the attacker are complete. Usually this task will be draining the money out of the contract until all of the money for every user is in the attackers account.
Example Scenario:
Let's say that you are using a bank and you have deposited 100 dollars into your bank account.Now when you withdraw your money from your bank account the bank account first sends you 100 dollars before updating your account balance.
Well what if when you received your 100 dollars, it was sent to malicious code that called the withdraw function again not lettingthe initial target deduct your balance ?
With this scenario you could then request 100 dollars, then request 100 again and you now have 200 dollars sent to you from the bank. But 50% of that money is not yours. It's from the whole collection of money that the bank is tasked to maintain for its accounts.
Ok that's pretty cool, but what if that was in a re-cursive loop that did not BREAK until all accounts at the bank were empty?
That is Re-Entrancy in a nutshell.So let's look at some code.
Example Target Code:
function withdraw(uint withdrawAmount) public returns (uint) {
Line 1: Checks that you are only withdrawing the amount you have in your account or sends back an error.
Line 2: Sends your requested amount to the address the requested that withdrawal.
Line 3: Deducts the amount you withdrew from your account from your total balance.
Line 4. Simply returns your current balance.
Ok this all seems logical.. however the issue is in Line 2 - Line 3.The balance is being sent back to you before the balance is deducted. So if you were to call this from a piece of code which just accepts anything which is sent to it, but then re-calls the withdraw function you have a problem as it never gets to Line 3 which deducts the balance from your total. This means that Line 1 will always have enough money to keep withdrawing.
Let's take a look at how we would do that:
Example Attacking Code:
function attack() public payable {
1.bankAddress.withdraw(amount);
}
2.function () public payable {
3.if (address(bankAddress).balance >= amount) {
4.bankAddress.withdraw(amount);
}
}
Line 1: This function is calling the banks withdraw function with an amount less than the total in your account
Line 2: This second function is something called a fallback function. This function is used to accept payments that come into the contract when no function is specified. You will notice this function does not have a name but is set to payable.
Line 3:This line is checking that the target accounts balance is greater than the amount being withdrawn.
Line 4:Then again calling the withdraw function to continue the loop which will in turn be sent back to the fallback function and repeat lines over and over until the target contracts balance is less than the amount being requested.
Review the diagram above which shows the code paths between the target and attacking code. During this whole process the first code example from the withdraw function is only ever getting to lines 1-2 until the bank is drained of money. It never actually deducts your requested amount until the end when the full contract balance is lower then your withdraw amount. At this point it's too late and there is no money left in the contract.
Setting up a Lab Environment and coding your Attack:
Hopefully that all made sense. If you watch the videos associated with this blog you will see it all in action.We will now analyze code of a simple smart contract banking application. We will interface with this contract via our own smart contract we code manually and turn into an exploit to take advantage of the vulnerability.
Then lets open up an online ethereum development platform at the following link where we will begin analyzing and exploiting smart contracts in real time in the video below:
Coding your Exploit and Interfacing with a Contract Programmatically:
The rest of this blog will continue in the video below where we will manually code an interface to a full smart contract and write an exploit to take advantage of a Re-Entrency Vulnerability:
Conclusion:
In this smart contract exploit writing intro we showed a vulnerability that allowed for re entry to a contract in a recursive loop. We then manually created an exploit to take advantage of the vulnerability. This is just the beginning, as this series progresses you will see other types of vulnerabilities and have the ability to code and exploit them yourself. On this journey through the decentralized world you will learn how to code and craft exploits in solidity using various development environments and test nets.
Just connecting to the service, a 64bit cpu registers dump is received, and so does several binary code as you can see:
The registers represent an initial cpu state, and we have to reply with the registers result of the binary code execution. This must be automated becouse of the 10 seconds server socket timeout.
The exploit is quite simple, we have to set the cpu registers to this values, execute the code and get resulting registers.
In python we created two structures for the initial state and the ending state.
On my last hollidays, I made two HTML5 games, and published on android market. Nowadays javascript has powerful libraries for doing almost everything, and also there are several compilers from java or c code to javascript, converting opengl c code to html5 canvas, but definitely, javascript execution is slower than dalvik applications, and of course much slower than arm c libs. For improving the speed of sounds and images loader, I have used javascript asynchronous execution and scheduling priority has been controlled with setTimeout/setInterval which deprioritize or priorize a code block. This games are published on the android market here: Android Planets and here: Far Planet
Based on work from Scott Sutherland (@_nullbind), Antti Rantasaari, Eric Gruber (@egru), Will Schroeder (@harmj0y), and the PowerView authors. Install Use the executables in the releases section. If you want to build it yourself, make sure that your go environment is setup according to the Go setup doc. The goddi package also uses the below package.
go get gopkg.in/ldap.v2
Windows Tested on Windows 10 and 8.1 (go1.10 windows/amd64). Linux Tested on Kali Linux (go1.10 linux/amd64).
umount, mount, and cifs-utils need to be installed for mapping a share for GetGPP
apt-get update apt-get install -y mount cifs-utils
make sure nothing is mounted at /mnt/goddi/
make sure to run with sudo
Run When run, will default to using TLS (tls.Client method) over 636. On Linux, make sure to run with sudo.
dc: DC to target. Can be either an IP or full hostname. Required parameter.
startTLS: Use to StartTLS over 389.
unsafe: Use for a plaintext connection.
PS C:\Users\Administrator\Desktop> .\godditest-windows-amd64.exe -username=testuser -password="testpass!" -domain="test.local" -dc="dc.test.local" -unsafe [i] Begin PLAINTEXT LDAP connection to 'dc.test.local'... [i] PLAINTEXT LDAP connection to 'dc.test.local' successful... [i] Begin BIND... [i] BIND with 'testuser' successful... [i] Begin dump domain info... [i] Domain Trusts: 1 found [i] Domain Controllers: 1 found [i] Users: 12 found [*] Warning: keyword 'pass' found! [*] Warning: keyword 'fall' found! [i] Domain Admins: 4 users found [i] Enterprise Admins: 1 users found [i] Forest Admins: 0 users found [i] Locked Users: 0 found [i] Disabled Users: 2 found [i] Groups: 45 found [i] Domain Sites: 1 found [i] Domain Subnets: 0 found [i] Domain Computers: 17 found [i] Deligated Users: 0 found [i] Users with passwords not set to expire: 6 found [i] Machine Accounts with passwords older than 45 days: 18 found [i] Domain OUs: 8 found [i] Domain Account Policy found [i] Domain GPOs: 7 found [i] FSMO Roles: 3 found [i] SPNs: 122 found [i] LAPS passwords: 0 found [i] GPP enumeration starting. This can take a bit... [i] GPP passwords: 7 found [i] CSVs written to 'csv' directory in C:\Users\Administrator\Desktop [i] Execution took 1.4217256s... [i] Exiting...
Functionality StartTLS and TLS (tls.Client func) connections supported. Connections over TLS are default. All output goes to CSVs and are created in /csv/ in the current working directory. Dumps:
Domain users. Also searches Description for keywords and prints to a seperate csv ex. "Password" was found in the domain user description.
Users in priveleged user groups (DA, EA, FA).
Users with passwords not set to expire.
User accounts that have been locked or disabled.
Machine accounts with passwords older than 45 days.
Domain Computers.
Domain Controllers.
Sites and Subnets.
SPNs and includes csv flag if domain admin (a flag to note SPNs that are DAs in the SPN CSV output).
Trusted domain relationships.
Domain Groups.
Domain OUs.
Domain Account Policy.
Domain deligation users.
Domain GPOs.
Domain FSMO roles.
LAPS passwords.
GPP passwords. On Windows, defaults to mapping Q. If used, will try another mapping until success R, S, etc... On Linux, /mnt/goddi is used.
"Aircrack-ng is an 802.11 WEP and WPA-PSK keys cracking program that can recover keys once enough data packets have been captured. It implements the standard FMS attack along with some optimizations like KoreK attacks, as well as the all-new PTW attack, thus making the attack much faster compared to other WEP cracking tools. In fact, Aircrack-ng is a set of tools for auditing wireless networks." read more...
"PHoss is a sniffer. A normal sniffer software is designed to find problems in data communication on the network. PHoss is designed to know some protocols which use (or may use) clear text passwords. Many protocols are designed to use secure authentication. For fallback they define a lowest level of authentication using clear text. Many companies use this lowest fallback definition as standard setting to make the product working in many environments." read more...
Spaghettiis an Open Source web application scanner, it is designed to find various default and insecure files, configurations, and misconfigurations. Spaghetti is built on Python 2.7 and can run on any platform which has a Python environment. Spaghetti Installation: Spaghetti's Features: Fingerprints:
Server:
Web Frameworks (CakePHP,CherryPy,...)
Web Application Firewall (Waf)
Content Management System (CMS)
Operating System (Linux,Unix,..)
Language (PHP,Ruby,...)
Cookie Security
Discovery:
Bruteforce:Admin Interface Common Backdoors Common Backup Directory Common Backup File Common Directory Common FileLog File
More information
