Hack your way out of planned obsolescence

When I was starting my current job I still thought that planned obsolescence in consumer stuff was bad enough. Now I still very much think that, but enterprise hardware is worse, so much worse! It’s almost surprising, you’d think that this is serious gear, for serious people, therefore it should be easily serviceable and indestructible, but in reality it’s nothing but a front for a much more lucrative operation. Support contracts.

So you’re telling me there are “commands”, but they are only for “support and partners”? Are my paws not blessed enough? Do I need to inject some corporate juice into my veins to wield such powers?

Bullshit. This particular problem was caused by a battery backup unit on a storage array being disconnected. The fuel gauge chip has a “Permanent Fault” flag that activates when that happens.

As it turns out there is a second MCU on the board, and it has its own CLI that is accessed through the BMC, and some commands in that CLI also have secret options that aren’t documented in the help command. One of them clears this evil flag, no magic hands needed. The only caveat is that it took me days of reverse engineering to fix this one small problem.

I wish I could go on and document everything that I’ve had to deal with out in the public for the world to benefit from, but sadly I do work for a business, and knowing how to fix things that vendors curse into being unfixable is how you make money, so leaking a bunch of secrets would not be great for keeping my employment. But I can share the process that got me here.

Step Zero: Reddit and ServeTheHome

Do some searching, add site:reddit.com or site:servethehome.com to your query. Those places are full of people who buy used gear and attempt to fix it, so you might find someone who already went through all this effort. You can also often find links to firmware and OS images that are normally behind a login wall.

Step One: Vendors are lazy

The first step to breaking into an enterprise-grade device is realizing that its creators are lazy. Most of those things run X86 and don’t have secure boot turned on, use that to your advantage. Dump the OS and inspect it.

What you will often find first is a bunch of scripts used for whatever the vendor’s flavor of restricted shell is. Those assholes love rbash and think it’s the best thing ever. They are however lazy as mentioned above, so you can pretty much expect to find the original comments in those scripts, which will be massively helpful for reverse engineering.

Grep, strings, and find are your best friends, search for any keywords that are related to your problem and then more keywords that you discover in those files. Don’t be scared of binaries either, as even grepping them might still give you some useful info.

At this point it’s possible that you’ve already found the solution to your problem, and if that is the case, great!

Step Two: Jailbreak

Still no solution? Maybe we need some good ol’ root access.

In most cases this is actually very easy, if there’s no secure boot and the device runs linux, just pull off the initramfs, extract it, and find whatever init script gets ran right before switching root. Insert a shell in there, repack it, done. Now you should be able to poke around and maybe change the root password, or edit a script that always gets ran with suid.

This also lets you deal with some devices that have an encrypted root partition and do funky shit like storing the decryption header in NVRAM.

With root access you can poke around on a live system, which makes it easier to figure out how it works, and you might be able to access some of those “support” shells that customers have been banished from.

Step Three: The big guns

Get yourself ghidra and start decompiling binaries that are interesting. It’s intimidating at first if you’ve never used it, but you will figure it out, I promise. You might also need a java decompiler, and maybe even something for python bytecode files (.pyc).

Most stuff won’t be obfuscated, so you can definitely just read through the code with some effort. If you’re willing to learn a bit of assembly you can also start patching some files, for instance if there’s a single “if” statement blocking you.

As much as I hate them, LLMs can also be useful for reading large amounts of decompiled code and figuring out what it does on a high level, use responsibly.

If all this is not enough, you might want to take a look at the database. A lot of devices run PostgreSQL or just sqlite, so if you connect to that you should be able to do some interesting things. Another thing you can do is look for external APIs the device may be calling, especially for issues of the licensing variety. You’d be surprised.

Don’t give up (quickly)

I know doing this may seem daunting at first, but just remember that all software is built on layers, and you can with enough effort peel those layers back over time. It might take days, or even weeks, but few things are truly as impossible as people on official support forums say.

The second time will be much faster, and eventually there will be nothing but secure boot that can stop you.

Also feel free to reach out to me in private if you have a problem with devices coming from a certain blue vendor, as long as you’re a creature made of flesh (or at least have a soul) I may be able to share more than out in public!

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