How we secure Monzo's banking platform • Hacker News Board

Re: How we secure Monzo's banking platform

#21

Post by anonymousDan » Mon, Apr 04, 2022, 9:57 AM UTC

carnitine wrote: post #7

andrewstuart wrote: post #5

Should banking really be on a cloud platform? I do believe AWS is likely far more secure than any DIY computing environment but even so, should banking be on cloud infrastructure? I'm not saying I think this is a bad idea but it came to mind when I read this. Also, is it really a good idea for a bank to be talking openly about its security strategy? Isn't an important part of security not to let on anything that migh…

I don’t see why banking shouldn’t be on a cloud platform, you’re not really giving any reason why we should question it either. As to your second point, security through obscurity is generally believed to not be worthwhile.

What about you are now exposing yourself to additional risks from e.g. a malicious employee at the cloud provider, or jurisdictional risk from FISA requests to the CP?

Re: How we secure Monzo's banking platform

#22

Post by csmpltn » Mon, Apr 04, 2022, 10:07 AM UTC

TruthWillHurt wrote: post #6

raesene9 wrote: post #2

Good to see some practices like default deny networking (ingress and egress) and very limited interactive production access being laid out here. A couple of other areas that aren't mentioned, although perhaps they're still doing them are around container breakout risks. There's no mention of what (if any)hardening is being done on the container runtime, either restrictive seccomp, Apparmor/SELinux policies or using s…

Exactly. containers are not secure sandboxes by default and if one is breached all those K8s networking ACLs are worthless.

> "Exactly. containers are not secure sandboxes by default and if one is breached all those K8s networking ACLs are worthless."

Your suggestion being? Putting a sandbox inside a sandbox? How many layers deep should this be, before being considered "secure"?

Re: How we secure Monzo's banking platform

#23

Post by KptMarchewa » Mon, Apr 04, 2022, 10:08 AM UTC

anonymousDan wrote: post #21

carnitine wrote: post #7

Earlier quoted context omitted.

I don’t see why banking shouldn’t be on a cloud platform, you’re not really giving any reason why we should question it either. As to your second point, security through obscurity is generally believed to not be worthwhile.

What about you are now exposing yourself to additional risks from e.g. a malicious employee at the cloud provider, or jurisdictional risk from FISA requests to the CP?

Why is risk from malicious employer in cloud provider somehow different from risk from malicious employer in colocation, or even private data center?

Re: How we secure Monzo's banking platform

#24

Post by andrewstuart » Mon, Apr 04, 2022, 10:10 AM UTC

carnitine wrote: post #7

andrewstuart wrote: post #5

Should banking really be on a cloud platform? I do believe AWS is likely far more secure than any DIY computing environment but even so, should banking be on cloud infrastructure? I'm not saying I think this is a bad idea but it came to mind when I read this. Also, is it really a good idea for a bank to be talking openly about its security strategy? Isn't an important part of security not to let on anything that migh…

I don’t see why banking shouldn’t be on a cloud platform, you’re not really giving any reason why we should question it either. As to your second point, security through obscurity is generally believed to not be worthwhile.

>> security through obscurity is generally believed to not be worthwhile

Is not advertising your security architecture "security through obscurity"?

Re: How we secure Monzo's banking platform

#25

Post by chrisseaton » Mon, Apr 04, 2022, 10:13 AM UTC

csmpltn wrote: post #22

TruthWillHurt wrote: post #6

Earlier quoted context omitted.

Exactly. containers are not secure sandboxes by default and if one is breached all those K8s networking ACLs are worthless.

> "Exactly. containers are not secure sandboxes by default and if one is breached all those K8s networking ACLs are worthless." Your suggestion being? Putting a sandbox inside a sandbox? How many layers deep should this be, before being considered "secure"?

I don't think this is the bottomless pit that you think it is. A virtualised instance is a lot more secure than a container, and it's probably fine to stop at virtualised instances.

Re: How we secure Monzo's banking platform

#26

Post by starfallg » Mon, Apr 04, 2022, 10:16 AM UTC

dmitriid wrote: post #20

andrewstuart wrote: post #16

Earlier quoted context omitted.

>> I don’t see why banking shouldn’t be on a cloud platform What if AWS gets cracked/hacked/compromised? I know it's not happened yet, but it's not impossible.

That's more or less the same question as "what if the data center/servers operated by the bank gets compromised". In reality it's always about tradeoffs: who to delegate to and who to trust.

>That's more or less the same question as "what if the data center/servers operated by the bank gets compromised".

The difference is that cloud relies on public services, which once compromised (e.g. via social engineering), allow for lateral attacks resulting in much bigger impact (e.g. Lapsus$) across the complete customer base. This makes social engineering much more attractive in cost vs impact. The resulting monoculture in not only the software, but the infrastructure and configuation also increase the impact on technical attacks on specific exploits.

Re: How we secure Monzo's banking platform

#27

Post by andrewstuart » Mon, Apr 04, 2022, 10:17 AM UTC

The biggest security hole for every organisation is its remote work from home workers.

I'd be interested to hear how this Monzo bank addresses the problem of someone walking in the home of one of their programmers and lifting access keys to AWS whilst that person is at the supermarket, and leaving with no-one the wiser.

Or installing a keylogger USB device onto their keyboard cable.

Re: How we secure Monzo's banking platform

#28

Post by mocko » Mon, Apr 04, 2022, 10:27 AM UTC

Disgruntled former Monzo customer here. Do they still have a haywire fraud detection system that randomly freezes innocent people's accounts? It's happened to countless users and the customer experience when they do it ("we refuse to tell you why" and in some cases holding onto their money for months) is a kafkaesque nightmare.

https://www.vice.com/en/article/bvg7n3/monzo-freezing-closin...

https://www.reddit.com/r/UKPersonalFinance/comments/db9j5z/m...

https://www.theguardian.com/money/2020/jun/06/monzo-customer...

I'd be far more interested in a blog post explaining that than how great their infrastructure is.

Re: How we secure Monzo's banking platform

#29

Post by gbrindisi » Mon, Apr 04, 2022, 10:32 AM UTC

andrewstuart wrote: post #27

The biggest security hole for every organisation is its remote work from home workers. I'd be interested to hear how this Monzo bank addresses the problem of someone walking in the home of one of their programmers and lifting access keys to AWS whilst that person is at the supermarket, and leaving with no-one the wiser. Or installing a keylogger USB device onto their keyboard cable.

It's not like office networks are a security paradise either

Re: How we secure Monzo's banking platform

#30

Post by csmpltn » Mon, Apr 04, 2022, 10:33 AM UTC

chrisseaton wrote: post #25

csmpltn wrote: post #22

Earlier quoted context omitted.

> "Exactly. containers are not secure sandboxes by default and if one is breached all those K8s networking ACLs are worthless." Your suggestion being? Putting a sandbox inside a sandbox? How many layers deep should this be, before being considered "secure"?

I don't think this is the bottomless pit that you think it is. A virtualised instance is a lot more secure than a container, and it's probably fine to stop at virtualised instances.

A lot more secure? In what ways?