Thursday, May 26, 2016

Anomaly with City of Toronto site security...

I ran across an anomaly on the City of Toronto website today....

They go to pains to point out that you're on a secure site in a weird "in-ya-face" way.  This is normally a red flag for me. People make a point of pointing out something when they believe your mind needs to be changed.  For instance, I'm told my burgers are 100% beef because someone in marketing thinks we have ideas that maybe it's not.  I'm told the latest cars are much more fuel efficient, because someone thinks I might have other opinions on this.  Now I'm being told in big message boxes that something is secure.  Mental red flag.

OK, let's suspend disbelief for a second and imagine that it actually is secure - where is the browser padlock?  

(Click for bigger version)

I clicked the "Close" button and then got to the next screen, where again it points out that you are in a secure site on the first line.  Again, there's still no browser padlock.  I also noted the usual bank-trade trick of proclaiming things are secure and placing the onus on the user to make sure they've done their bit for security.... even though the padlock is still missing.

(Click for larger version)

So, I took a quick look at the certificate. The first thing you notice other than the City of Toronto is apparently in Macau, is the verification error that this is a self-signed certificate - so this is no more valid that if I generated one here on my computer and delivered it on a USB stick to City Hall. I've highlighted both items in red.

Jasons-2013-MacBook-Pro:~ jasoncoulls$ echo ^d | openssl s_client -connect
depth=3 C = US, O = "VeriSign, Inc.", OU = Class 3 Public Primary Certification Authority
verify error:num=19:self signed certificate in certificate chain
Certificate chain
 0 s:/C=CA/ST=Ontario/L=Toronto/O=City of Toronto/OU=Technology Infrastructure Services - macau-w1/
   i:/C=US/O=VeriSign, Inc./OU=VeriSign Trust Network/OU=Terms of use at (c)10/CN=VeriSign Class 3 Secure Server CA - G3
 1 s:/C=US/O=VeriSign, Inc./OU=VeriSign Trust Network/OU=Terms of use at (c)10/CN=VeriSign Class 3 Secure Server CA - G3
   i:/C=US/O=VeriSign, Inc./OU=VeriSign Trust Network/OU=(c) 2006 VeriSign, Inc. - For authorized use only/CN=VeriSign Class 3 Public Primary Certification Authority - G5
 2 s:/C=US/O=VeriSign, Inc./OU=VeriSign Trust Network/OU=(c) 2006 VeriSign, Inc. - For authorized use only/CN=VeriSign Class 3 Public Primary Certification Authority - G5
   i:/C=US/O=VeriSign, Inc./OU=Class 3 Public Primary Certification Authority
 3 s:/C=US/O=VeriSign, Inc./OU=Class 3 Public Primary Certification Authority
   i:/C=US/O=VeriSign, Inc./OU=Class 3 Public Primary Certification Authority
Server certificate
subject=/C=CA/ST=Ontario/L=Toronto/O=City of Toronto/OU=Technology Infrastructure Services - macau-w1/
issuer=/C=US/O=VeriSign, Inc./OU=VeriSign Trust Network/OU=Terms of use at (c)10/CN=VeriSign Class 3 Secure Server CA - G3
No client certificate CA names sent
SSL handshake has read 4853 bytes and written 636 bytes
New, TLSv1/SSLv3, Cipher is AES128-GCM-SHA256
Server public key is 2048 bit
Secure Renegotiation IS supported
Compression: NONE
Expansion: NONE
No ALPN negotiated
    Protocol  : TLSv1.2
    Cipher    : AES128-GCM-SHA256
    Session-ID: 00000D2AD210CD02429618321FAA1D60105219435858585857471DBB000016D0
    Master-Key: DDEF69EA999B9A7FA1AAA0AE94D5F3A00F5F9FF5F47D854BAC1621B018CC81751C17BCE855B6FE497AD99445EAE5830C
    Key-Arg   : None
    PSK identity: None
    PSK identity hint: None
    SRP username: None
    Start Time: 1464278459
    Timeout   : 300 (sec)
    Verify return code: 19 (self signed certificate in certificate chain)


So, there you have it.  Whilst the city tells you it's secure, both the browser and the openssl tool verification gives errors or refuses to show the padlock.

Wednesday, May 25, 2016

Finally, a bank listened.

Anyone that has the smallest bit of familiarity with me will know that I keep a keen eye the security of Canada's banks and telcos, especially those that I know are putting me or my family at risk.  I might sound like a crackpot at times to some people, but those that know me well all know that I'm not going to publicly say something if I couldn't substantiate it.

Over the past month or so, I've spoken to each of these organizations in turn (sometimes I reached out to them, other times they phoned me first), as my concern levels are now at an all time high.  Some banks flat-out said they were not going to entertain the idea of paying me for my time to explain their problems, and that's their decision - I work in IT and I'm not working for free.  Some banks couldn't answer one way or the other as to whether they will or won't entertain the idea, and one bank positively jumped on the opportunity to hear me out.

It's no secret that I consider much of Canada's banks to be a security disaster in motion; I've been saying for years that things are broken.  Things have been surreal at times (for instance trying to fool the bank security into thinking my dog was me), and other times I think I'm moving forward only to find myself going backwards again.  As time has gone by (and especially recently) what started off as my documentation of a small set of issues with a few root causes with one bank has snowballed to something really huge that now spans the entire Canadian financial system and expands out of it in all directions.  

Obviously, I'm not going to say what I found, but it's an uncomfortable situation having the knowledge of what an amazingly precarious situation we are all in.  I know what's broken, what's not being tested. What is likely to be the major vectors to breach most banks and what went wrong in policy to allow this to happen.  So, when I see Twitter feeds from these banks telling their customers that their online banking is guaranteed secure, it makes me cringe because I know it's not secure.  I also know that if I know it's broken, others will know that too.  Of course all the banks in Canada have a standard public mantra throughout this of "It's secure until YOU lost your acct # or password" as if they believe it could never be them at fault for a breach, even though I know they're likely already compromised and they've more than a small chance of compromising other external organisations in the process.  

Now, I don't have to get into a convertible car with the top down to know that if it rains in the future that I'll get wet, because I know and understand what I'm looking at. It's like if a bank gives me an address of a branch in a town I've never visited, I can guess accurately that at night, they can't see the sun from that branch.   Same thing applies to digital banking at most banks in Canada - you don't have to hack them, go into them, or do anything untoward to them to know where and how they can be compromised.  

So, bearing the above logic in mind, I sat down with this bank and explained what's going on in Canada.  Like the car or sun analogy above works with the average person, what I had to say worked with bank security people.  So, I covered how Canadian's are at risk with their mobile apps, how the banks online banking systems are mostly all broken and then covered the security circus that we know of as Interac.  They got it immediately - I didn't have to explain a thing...

...and then I dropped the "Here's the really, really, bad side-effect of this" bombshell.  They got that too - understood it, crystal clear.  Not a single "You're wrong!".  No mention of "That's impossible!".  There was not a single ounce of disagreement.  Finally, after a very long time, I was talking to a major bank and they're like "Everything you say is understood".  

In a surprising twist, after being asked if I've ever considered a career in bank security, I actually got asked my thoughts on the SWIFT situation?  I had an immediate four point answer on what's broken (it needs certs on messages, cert-pinning with clients and servers, hashing of messages to stop alterations and a central pub-sub number authority to stop message injections in the sequence), but as I answered, I couldn't help thinking how far this situation had turned around; Usually big banks argue against me, and now here I was, being asked my opinion on how I'd fix the largest bank messaging system in the world.

This makes a big change from the status quo.

Whilst I have no idea what'll happen next with this particular bank, my immediate job is done. They know what I know and now hopefully there will be action as a result.

As for the other banks?  Well, time will tell if any come back to the table.

Sunday, May 15, 2016

How the Swift bank messaging heist will affect Canadian banks

If you've been paying attention to the news lately, you'll know that a large sum of money just got removed in a heist on the Bangladesh central bank using the SWIFT system.

First, a bit of background to explain what the mainstream media doesn't explain clearly...

The SWIFT messaging system doesn't actually move money itself and it keeps no account numbers or ledgers for the banks it goes between, or the money being instructed to move.  All it does is says "Bank A needs to settle this transaction with you" to Bank B.  It's then down to Banks A & B to sort that out between themselves.  You can replace SWIFT messages with a carrier pigeon note, or a note tied to a brick and though these are less secure than SWIFT messages and slower moving, it wouldn't actually make a blind bit of difference to the banks as far as money moving goes because this is down to the banks to achieve.

So, now you're up to speed, let's ask see what happened?

In plain English (and simplifying things immensely), what happened is this:  Robbers targeted the SWIFT (Society for Worldwide Interbank Financial Telecommunication) messaging system.  They simply added a few bogus SWIFT messages into the pipeline instructing the Bank A (Federal Reserve Bank of New York) to send money from the Bangladesh central bank account to a bunch of other banks in other countries.  Of course, the banks just blindly did what they were told.  Five messages went through and were settled to the tune of $81million, and then someone noticed a mistake in the sixth message and questioned things and this is when the messages were all discovered to be bogus.  The backlog of 30 messages not yet processed were totalling $850million.

How does this affect the Canadian banks?

The SWIFT heist wasn't an isolated incident.  The people that pulled this off knew that the banks considered themselves to be secure, but that security could be bypassed.  In Canada, we also have the SWIFT system, so the same risks apply to Canadian banks if they're not secure.  We also have a similar system for consumers in the form of Interac.

Just like SWIFT, Canada's Interac system doesn't move money either.  It sends messages to move money, and the banks figure out how they'll do that at the end of the day.

In plain English, it looks like this:

Bank A deducts $50 from Mr Jones who wants to send to Mr Smith. 
Bank A:  I've got $50 from my customer Mr Jones, for your customer Mr Smith.
Bank B:  OK - I'll add $50 to Mr Smith's account.

Mr Smith can now spend that money immediately.  At the end of the day, when the banks settle, this happens:

Bank A to Bank B:  I owe you $50.
Bank B to Bank A:  Well, I owe you $60 from an earlier transaction, so here's $10 and we can call it quits.

There's a lot of parallels to the SWIFT system in that it's purely based on trust.  This is the first problem.  For Canada's banks, they need to now harden up security on two systems that are kinda flakey if you don't do things correctly (SWIFT has strict procedures on how Banks should do things).  This trust issue is key to the whole security problem in Canada.  You have banks trusting each other - and trusting Interac - and customers trusting Interac and trusting the banks.

This is where the wheels fall off this wagon...  I reported to CIBC in January that Interac's servers were not secured properly from an SSL standpoint.  They fixed that in April, but there's two bigger underlying issues and I'll touch on one right now.

Let's imagine you are writing an iOS app in Canada and need to take debit cards.  You call Interac and they're like "Go away - we don't deal with the public -  go talk to one of our authorized integration partners".  So you deal with the integration partners who then have no sway over Interac to fix things when the situation goes sideways.

I've actually gone through this, where an iPhone had a 320 pixel wide screen, and some tool at Interac had hardcoded their CSS to 640 pixels wide, thinking that no computer would ever access their system on a screen less than 640 pixels.  So, I phone the integration partner and they phoned Interac. After a few days, the official word was Interac weren't going to change this.

How did I fix this?  Well, I did what everyone else did back then; you take Interac's broken CSS, fix it and store it in your app as a bundled resource.  Next, you make your normal calls to Interac's computers to initiate the transaction, get the HTML and CSS response, and you simply switch out their busted CSS and replace it with your own fixed CSS.  It's not like Interac ever designed anything to detect this kind of meddling.

If you're technically minded, you probably just realised this is the equivalent as a man-in-the-middle (MITM) attack.  Yes, it's common in Canada, that when Interac doesn't want to help a situation, you just code around them.

Of course, if you can switch the CSS (which determines how things are laid out) you sure as hell can change the HTML (the message the customer sees).  That's scary.  So, Interac is going to have to finally get it's act together and tighten up security...  As it stands, Interac can be compromised in two ways that I know of.

What about the banks themselves?

They are likely being told the same as everyone else - which is harden up.  This is a problem, though:  If you look (in Toronto, at least) at the banks and their current hiring process, you can see predictability - if it's a bank, it will think like a bank and it will act like a bank and it will hire the same type of security people that it did before.  That predictability combined with a sense of trust that the banks know what they are doing is where the danger is in Canada.

Here's a current security post from CIBC as an example:

If you're not quite sure of what you're looking at, let's break this down:
  • Right now, they want more of the same type of people that they hired to guard about 50 servers and all their technology infrastructure in 1998.  You're certified for the bank, fit the bank's culture and think and act like you belong in a bank...
  • It's not 1998, and smartphones came out in 2007, social engineering took off, the two gender tick boxes for customers are not enough to define people, and now customers are attacked outside the bank because they're mostly fighting the wrong war. 
When faced with an attack surface of some ten million devices and computers in Canada, that a technically curious average 15 year old can circumvent in two days, it's apparent that some Canadian banks are not in the same security arms race as their customers.  This means it's technically more feasible to compromise a bank through compromising it's customers.  That job above didn't even mention mobile, despite that being a massive vector for attacks caused by most bank's own ineptitude.

I will leave you with one last screenshot I pulled off Twitter two days ago.  Note the "1/4" response and how confident the bank is that they are secure and the insinuation that any failure that might happen will be the fault of the customer.  This is scary considering how broken the security is.

This is what I lose sleep over.