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How we secure Monzo's banking platform

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Re: How we secure Monzo's banking platform

#141

Post by TruthWillHurt »

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"?

Opposite - don't mess with sandboxing. Use PaaS services like its > 2008, and let AWS / Google security teams harden their platform.

Re: How we secure Monzo's banking platform

#142

Post by detaro »

csmpltn wrote: post #126
chrisseaton wrote: post #68

Earlier quoted context omitted.

Genuinely, would you be happy with just container isolation between you and other customers of your cloud provider? Most people absolutely would not.

> "Genuinely, would you be happy with just container isolation between you and other customers of your cloud provider? Most people absolutely would not." But that's exactly how VPS hosting works today - you don't get your own private blade unless you're ready to pay premium prices and have the competence needed to run them yourself. The technicalities of how private resources in a VPS are isolated from each other wil…

No, VPS hosting is not usually container-based today once you leave the utter bargain-bin offers. The difference between VM isolation and container isolation is quite significant.

Re: How we secure Monzo's banking platform

#143

Post by benhurmarcel »

nvarsj wrote: post #65
mocko wrote: post #28

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/U…

Happy Monzo customer here with it as my primary account for the last 2 years. Haven’t had any issues, and neither have any of my friends. It’s the best possible banking experience imo. I’m happy they are proactive about suspicious activity.

https://xkcd.com/937/

Re: How we secure Monzo's banking platform

#144

Post by staticassertion »

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…

> With this year's number of container breakout CVEs, seems like an important area.

Worth noting that even basic hardening in docker will prevent a lot of them. I say "in docker" because K8s disables seccomp, which matters a lot since `unshare` is denied by docker's seccomp and is very useful for attackers in a container. If you use Docker the main thing to do is just not run as root.

If you do that much, and it's not hard at all, you are in a much better place than a default k8s pod.

Re: How we secure Monzo's banking platform

#146

Post by melevittfl »

YawningAngel wrote: post #117
stavros wrote: post #53

Earlier quoted context omitted.

The link doesn't really clarify much for me, can you elaborate? Are you saying the GP laundered money?

I'm saying that the bank gets royally fucked if they ever tell anyone who is even suspected of money laundering anything, so as a result they simply don't tell anyone anything. Whether the GP actually did it or not isn't really relevant because banks would rather lose a customer than incur the regulator's ire.

I’m sure you know this, but it’s not just regulator’s ire. It is a criminal act in and of itself to disclose that someone is a target of an investigation.

And it’s not just a criminal act for the organisation, but the individual customer service agent can be held personally criminally liable for disclosing, even accidentally.

So yeah, they have a really strong incentive not to tell you anything.

Re: How we secure Monzo's banking platform

#147

Post by youngtaff »

staticassertion wrote: post #124
kasey_junk wrote: post #69

Earlier quoted context omitted.

Most serious security teams do not consider containers a security boundary. So it’s not a sandbox inside a sandbox, it’s just a sandbox. Gvisor and firecracker are the most popular sandboxes for containerized workloads.

I think this is outdated. Docker is a security boundary. There is no built-in way to get out of a Docker container just by asking by default (if you mount the socket into the container, it's trivial). How good of a boundary it is may be another story. There's some seccomp filters going on and namespacing is pretty sweet too. But an attacker can escape by exploiting the kernel, which I think most security people would…

Using the Dirty Pipe Vulnerability to Break Out from Containers

https://www.datadoghq.com/blog/engineering/dirty-pipe-contai...

Re: How we secure Monzo's banking platform

#148

Post by staticassertion »

youngtaff wrote: post #147
staticassertion wrote: post #124

Earlier quoted context omitted.

I think this is outdated. Docker is a security boundary. There is no built-in way to get out of a Docker container just by asking by default (if you mount the socket into the container, it's trivial). How good of a boundary it is may be another story. There's some seccomp filters going on and namespacing is pretty sweet too. But an attacker can escape by exploiting the kernel, which I think most security people would…

Using the Dirty Pipe Vulnerability to Break Out from Containers https://www.datadoghq.com/blog/engineering/dirty-pipe-contai...

Yes? There are a million exploits that allow breaking out of a container. I didn't say it was some impenetrable force field, I said it was a security boundary.
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