Oraclewizard.com, Inc is a Veteran Owned HUBZONE Certified Small Business, Principle owner Robert Lockard is an Oracle ACE Director and Winner of the 2015 Oracle Developers Choice Award for Database Design.
I learned this morning a dear friends elderly relatives received a number of calls from someone claiming to be from their bank. I won’t go into all the issues; however there are some things everyone should be aware of. BTW: This not only applies to banks, this applies to any call you receive (Bank, IRS, Police, Insurance Company). There are a lot of criminals out there, please, don’t be a victim. For those who don’t know me, I spent twelve years at Financial Crimes Enforcement Network (FinCEN) I know a bit about this.
Remember the criminals top priority is to steal from you.
Your bank will never call you and ask for personal information. Sometimes this is hidden with, “we must verify your identity.” Bottom line, your bank will not do this. This is a trick to steal from you.
It is very easy to spoof a phone number. Do not trust the phone number that is displayed.
If you receive a call from someone claiming to be from your bank, get their Name, Phone number, and department. Then call the bank at a phone number you know is good and ask to be connected.
If the bank can’t find that person, ask to speak with the fraud department. They can investigate.
These call will try to create a sense of urgency, that you must talk to them now. Do not fall for it. This is just another trick criminals use to steal from you.
Last piece of advice, Hang up the phone and block the number.
This morning I learned of a young friend who was scammed out of some money online. Things like this always make me angry and I did not think I would ever have to post something like this because we all know these things right? Well no, some people have not been exposed to criminals and are trusting souls. This is for you gentle souls out there; and hope you don’t have to become callous and paranoid like me.
I spent about twelve years working in Financial Crimes (FinCEN), combined with being the Information Security Guy; you listen to me, this is something I know a great deal about.
Rule #1: I live by simple rules. Simple rules have kept me alive for almost 59 years; simple rules work.
Rule #2: When it comes to dealing with anything that has to do with money and the internet – be paranoid, be very paranoid. I always assume the person on the other end is a criminal, because there is a very high probability the person is a criminal.
Rule #3: If someone is offering to pay you money, they will not ask for any kind of payment from you. If you are asked for a payment, even a tiny amount this is a scam. You are dealing with a criminal who wants to steal from you.
Rule #4: If someone is offering you something of value for a service, opinion, survey, etc, they will not ask for any kind of payment from you. If you are asked for a payment, even a tiny amount, this is a scam. You are dealing with a criminal who wants to steal from you.
Rule #5: If you believe someone is a public figure and they are asking you for money or anything of value, it is a scam. You are dealing with a criminal who wants to steal from you.
The book I’m currently working on is a technical book on Database Application Security. While writing, I frequently find myself trying to explain something and I can’t quite come up with a good explanation. This normally indicates I don’t understand something well enough to explain it; therefore it goes into my “What I don’t know book.” (we can discuss that another day.)
So I’m working on a book, and get stuck. The first thing I do is write down what I don’t know in the form of a question. Case in point, working on the Unified Audit section and I wanted to explain, “how come unified audit does not immediately write to the database, you have to turn immediate write on.” Many years ago, I learned not to go with the first answer that comes to my mind. It may be right, it may be wrong.
To keep me moving forward on the chapter, I could either 1) start researching the answer and wind up going down a rabbit hole. Or 2) I can insert the question into the chapter in the form of a question.
<QUESTION> why does unified audit pause writing to the database? </QUESTION> Then scribble that same question into the notebook I carry with me.
I choose to use #2, because it allows me to stay focused on writing. I can then come back to the question, do my research and get an accurate answer.
Inserting and tagging questions is a great way to keep the focus on the work you are currently doing. You can research later, then maybe talk a walk and ponder just how your are going to answer the question.
I’ve been doing this a long time, and there two infosec errors that I keep seeing. Granting DBA to an application and people using the application account. The problem of granting DBA to an application account is compounded when people actually logon to the application account to work.
Oracle has the DBMS_PRIVILEGE_CAPTURE package that is now licensed to Enterprise Edition. It’s a powerful tool to fix over privileged accounts; yet when someone logs on as the application to do dba work, then all bets are off.
1) Don’t grant DBA to application accounts. Figure out what privileges the account needs and grant those privileges.
2) Don’t use an application account to do your work.
3) Use the DBMS_PRIVILEGE_CAPTURE package to analyze what privileges your users are using and dial back over privileged accounts.
When using ENCRYPTION_PASSWORD with expdp and impdp, your history file (ie .bash_history) will store the password in plain text and if you’re sending the password over the wire, your network better be encrypted.!!!!!
It’s been a wild and crazy year. I could write this about all the data breaches we had in 2018, that would be too depressing. Instead I’m going to focus my favorite cities
I filled up my passport and now need a new one, so I ordered the larger size one. The down side is, I need to apply for another Russian visa, when I still have time left on my current visa. I hit all my major goals this year, made some new friends, had the privilege to speak at three universities, and added a couple more favorite cities to my list of, I’ll stop here for a couple days and rest.
Those cities are:
Moscow – UPDATE Sadly Russia is now too dangerous to visit and I don’t see the situation changing in the near future.
Lawmaker Leonid Kalashnikov July 2018: re: Maria #Butina‘s arrest: “Let’s arrest an American here and that’s it… They arrested Butina, let’s immediately arrest some Amerikashka here.” Now we have the arrest of Paul Whalan in December 2018.
There is the Bolshoi, the Metropol, food, wine, spirited people, rich history, decorated walking streets, and great friends. One thing I learned is Russians are a warm and friendly people. If your lost, need help, or just curious, I’ve found Russians are always willing to step up and help a stranger.
Belgrade – This city has a deep history. The food, people, architecture, art, great friends, and streets you can walk on.
Helsinki – when it’s warm. The people, friends, and food, just don’t ask the lady in the elevator where the polar bears are. Trust me, I asked; she looked at me like I was a very strange person.
Sofia – I always put on weight whenever I visit Bulgaria. The food is to die for, the people are friendly, and the streets that were made for walking.
Of course, there is also, London, Paris, and Kraków.
See y’all in 2019. Lets make it better than 2018, that’s saying a lot. 🙂
Did you know when you type commands in sqlplus or sqlcl that include a password; if your network is not encrypted, the password is sent in the clear. In fact, all sql commands are sent in the clear to the database if the network is not encrypted.
Great for a man in the middle attack. Make sure your network is encrypted before you start configuring the Oracle database or sending sql statements for that matter.
<code> c##sec_admin > administer key management set keystore open identified by SecretPassword;
Us technical nerds have a way of talking to each other, mostly we understand each other, sometimes we don’t and frequently we throw out buzzwords, thinking everyone must know what we’re talking about. This paper is going to address the subject of blockchain so anyone with a non-technical education can understand what it is and how it works. You may not be able to develop your own blockchain after reading this paper, but you’ll have a good handle on what us nerds are talking about..
There seems to be some confusion about just what blockchain is. Many people I speak with automatically assume blockchain is Bitcoin. First off, Bitcoin (and other cryptocurrencies) are not blockchain and blockchain is not bitcoin. Bitcoin uses the secure data structure of blockchain to protect the data. Now because blockchain was described by Satoshi Nakamoto in 2008 to describe a Peer to Peer electronic cash system, and Bitcoin was the first application to utilize the security aspects of blockchain, this confusion is understandable. Now that we have established that bitcoin is not blockchain and blockchain is not bitcoin, lets address what blockchain is. Blockchain is a way of linking transactions using a timestamp and cryptologic hash into a linked list to make the data immutable. Yea’ that’s a mouth full. But if you do much reading on blockchain, there have been some enhancements to what we can do besides making data immutable. The power of blockchain lies in, if you change anything in the blockchain, you break the cryptologic hash.
Here we see two blocks that have been joined by block 1’s current hash to block 2’s previous hash. This is a simple linked list. Data is linked to other data by pointing to a unique value of its neighbor. Also a linked list can not have any branches, so in this instance we can not have two pieces of data pointing back to the same unique value of a neighbor.
Let’s start taking this apart, to see what is actually happening and I’m going to start by defining what a hash is, what are the qualities of a good hash, and a tiny bit about how hashes work.
A hash is a one way cryptologic function that produces a value from some input. So if I pass to a hash function, “the rain in Spain falls mainly in the planes.” the SHA256 hash function will produce: 4f5960e9f8aa23073bd14dfe85cce5020530e15f1f7dc4231d16cceb01d09e70. Now if I change one letter of the text to “The rain in Spain falls mainly in the planes.” (just switching the t from lower case to upper case) The SHA256 hash function will produce: 5cadf57561ce0e294dd4c7b982be6ffad0c81281f0d6ab6fa64efccdfaf51061. As you can see two totally different results that don’t even remotely resemble each other. I have read from many respected sources, the SHA256 hash is guaranteed to always return a unique value. This is not exactly a true statement. SHA256 produces an output of finite length, however there are an infinite number of combinations that can be passed to a hash function. Eventually, someone will find a hash collision (when two different inputs produce the same output) but for all practical purposes, it will produce a unique output for any given input.
The last thing you need to understand about hash functions, you should never be able to take the hash and find out what the original input was. That is if I was to give you this hash from SHA256 5cadf57561ce0e294dd4c7b982be6ffad0c81281f0d6ab6fa64efccdfaf51061 you should not be able to figure out what the input is. You may already see the problem with this statement. Because I used this hash in a previous example, you can go back and read what my input was. Because we know the input and we know the hash we can run it through the function to see if the message has changed. If they stay the same, we’re golden, if not, the text was altered.
Difficulty: Tthe time to calculate a hash is amazingly fast, my last test was producing a SHA256 hash on a small input in 0.001001119613647461 seconds,. Yup, that’s pretty quick. So, we actually need a way to slow down the ability to produce a hash so we introduce a difficulty factor to it. We do this by creating an artificial requirement that the hash must start with one or more zeros. In reality you can use anything you want; however the current standard people are using, is starting the hash with 0’s. Each time we increase the difficulty, the time to calculate the hash increases exponentially. So with a difficulty of two zero, the average time to hash is 0.003002166748046875 seconds and a difficulty of three zeros the average time to hash is 0.2151656150817871. A difficulty factor of four and it took 200.69477248191833 seconds to calculate the hash. This is a pretty old computer I’m working on right now, so faster speeds are possible, but you get the point, as the difficulty increases, it becomes much harder to calculate a hash with the required difficulty.
The reason we are adding in a difficulty factor is to slow down the ability to rebuild the blockchain and defeat the security that is built, by linking the data (blocks) with a hash. So, if the speed to calculate the hash is slow, a potential attacker would need much more CPU power then the machines building the blockchain to change some data and then recalculate all the hashes in the blockchain, and then get ahead of the machines building the blockchain.
I promise if your not a techie, this is not that painful. What I want you to see is the technique that I used to calculate the hash with a given difficulty.
def f_calc_hash(self, data, nounce, difficulty):
s_curr_hash = sha256(data.encode()).hexdigest()
while not s_curr_hash.startswith(‘0’*difficulty):
self.nounce += 1
data = data + str(self.nounce)
s_curr_hash = sha256(data.encode()).hexdigest()
This is actually pretty easy to read, we have a function to calculate the hash with the required difficulty. It takes the data we want to hash, a nounce that I’ll get to in a minute and our difficulty factor. It starts by calculating the hash and checks to see if it starts with the required number of 0’s. If it does not, then it adds 1 to the nounce, and puts that number at the beginning of the data we are hashing. Because we have now changed the data, we will get a different hash. We continue adding 1 to the nounce and testing the hash to see if it meets the difficulty requirements. If it does, great, return the hash, if not, keep adding 1 to the nounce and getting the hash again. There is no way you can figure out what nounce to use, therefore, the only way to get a hash with the required difficulty is to use brute force.
So a Nounce is just a variable we use to add to the data we are hashing to get a different hash. That’s all. Where the term nounce came from, I don’t know.
We also add a Timestamp to the transaction to prove when the transaction was created and also in some cases to make sure the transaction is unique and we can get a unique hash for each transaction.
Transactions all go into a Block. You can have one or more transactions in a block, the number is up to you and the requirements for your system.
So let’s use the simple example of a check register. These two transactions can go into a block to be added to the blockchain.
05 May 2018
05 May 2018
Before we go much further, we need to explain how to weld blocks together using a hash that meets the difficulty requirements.
All blockchains start with a Genesis Block, this serves as the anchor to the blockchain by providing the first hash needed to weld the blocks together. There is one special thing about the genesis block, it does not have a prior hash in its header. There is one other thing about the genesis block you should understand, The data in it may not be of any value. It’s just a seed for the rest of the blockchain. When we have built the genesis block, we get a hash that meets the difficulty requirements and put that in a field called current_hash.The Current_hash is the hash value we get when we calculate the hash with the required difficulty factor using the calculated nounce.
So when we add in block#2, it copies the current hash from the genesis block into the previous hash field. We then hash the block to get the current hash and nounce that meets the difficulty requirements. By joining block# 2 to the genesis block, we now have a blockchain with two blocks. Every block we add to the blockchain, we repeat this process.
Why is the data structure so powerful? Let’s start with the assumption that we have a blockchain with 10,000 blocks. If someone were to change one piece of data, say in block 500, then the current hash in block 500 would not be right anymore. Let’s say our hacker is clever and calculates a new nounce to get a hash that meets the difficulty requirements. Well then the previous hash for block 501 would not match the new hash that was calculated. So, the hacker now has to calculate a nounce for block 501 and to get a hash that meets the difficulty requirements. Then, 502, and 503, on and on. It would require a lot of CPU to recalculate the entire blockchain. If we did not have a difficulty factor built into the blockchain, the speed to calculate a hash is pretty darn quick. That difficulty factor puts a speed limit on just how fast you can write to a blockchain. Pretty darn clever if you ask me.
Anonymity vs Known Users or Public vs Private blockchains. We have the very basics of what a blockchain is, now we can look at a couple of different types of blockchains. First there is a public blockchain where anyone can add data to the blockchain. The typical public blockchain is cryptocurrencies such as Bitcoin. Note: Cryptocurrencies are also frequently called shadow currencies. In cryptocurrencies, anyone can add blocks to the blockchain and make money. Here everyone has a copy of the blockchain and when you add to the blockchain, you provide a proof of work and other nodes in the blockchain check your work. If you met the required difficulty and the nounce is correct, then your block is added, that is unless another node has added more blocks then you. Because we can not have branches on a blockchain, the network uses the node that is longest as the valid blockchain.
When we say branches, that means two or more blocks using the current hash of a previous blocks as their previous hash.
So now that we understand what a public blockchain is, let’s explore what a private blockchain is.
In a private blockchain only computers (nodes) that are invited in can participate. Private blockchains can be used to store medical information that has regulatory protections, supply chain management, and trade between businesses.
In the public blockchain, we used proof of work to add data to the blockchain. In the private blockchain we use Selective Endorsement by using Endorsing nodes. Endorsing nodes are the machines that are authorized to add data to the blockchain. The endorsing nodes can be one node, many nodes, or all the nodes on the private blockchain.
When we have multiple entities on a private blockchain, not everyone is allowed to see all the data in the blockchain. We enforce this by using channels. If you are dealing with financial or healthcare data, you must control who has access to the data. When a government, business, or person joins a private blockchain, they subscribe to a channel. The simplest way to describe a channel is it is a standalone blockchain that is shared betw*een players on the system.
A member of a private blockchain can subscribe to one or more channels. In this example Org1 is subscribed to both channel 1 and channel 2. Org2 is subscribed to channel 1 and Org3 is subscribed to channel 2. Now, the beauty of this is, the data has been segmented. That is to say, nothing in channel 1 can appear or be written to channel 2 and nothing in channel 2 can appear or be written to channel 1. Each of these channels is in fact, a private blockchain.
What can we do with this? Glad you asked, because the information has not been changed, we can use the data in the blockchain to trigger Smart Contracts.
Smart contracts are a way to trigger an event after conditions are met. A simple example of a smart contract would be to send payment to a vendor. This would be accomplished with a simple if .. then .. else statement. In a purchasing blockchain a Smart Contract may exists that says, IF Shipment Received AND Shipment Verified AND Invoice Received AND Matching Purchase Order THEN Pay Invoice. Smart Contract are a good way to speed up the flow of business processes by embedding logic into the blockchain that all parties agree to.