Hi. Just a collection of random thoughts and technical dumps on things I sometimes look at or work on.

NBN Location ID checksum/check digits

Edit 11/09/2020: It’s occurred to me that the AVC numbers may conform to this as well, and it appears they do. (Albeit to the sample size of 1 because I don’t have access to anyone else’s AVC except my own) Just noting down that NBNCo Location ID’s use the Verhoeff algorithm to generate their check digit, since nobody appears to have mentioned it in a Google-indexed, website to my knowledge....

October 22, 2020

Exploiting CVE-2020-8597 to get RCE on a locked down router

So it’s late February 2020 and we’re all starting to realise that we’re going to be sitting at home for a while. Some are cleaning, some are baking, and some of us order cheap routers off of AliExpress to flash and replace their old hardware with. I picked one of these, as the specifications seemed quite decent in comparison to the price that was being asked. (There is an almost identical in specifications unit being sold by the same manufacturer here, which through some sort of horrible coincidence has the exact same memory layout and ROP gadget addresses)...

June 7, 2020

Nvidia’s CPUId Lockouts

Late 2021 edit: They finally removed this in their driver now, so now they can be used in passthrough setups with their binary drivers. It appears that the Nvidia GPU drivers (both the Windows and Linux ones, after a certain point) don’t particularly want to be run under a hypervisor Microsoft Hv (The Hyper-V vendor id) VMWare VMwareVMware XenVMMXenVMM KVMKVMKVM Parallels In addition, some of these model specific registers from KVM (the KVM wallclock) arbitrarily anger their drivers....

September 10, 2015

Editing Device Checks for Fun and Profit

Recently, I heard a certain game was giving away items to owners of a certain new device (The Motorola Droid Ultra and the Motorola Droid Maxx). Since I don’t live in the USA, and don’t particularly want a phone with a locked bootloader, or one labelled “a phone that doesn’t need to exist”, let’s break the APK apart and see what we can do. Let’s take a look at how they are checking for these devices....

August 14, 2013