Reverse engineering my router's firmware with binwalk

The primary reason is likely because the hardware (SoC peripherals) drivers were written for 2.6.x and not forward ported to newer versions of the linux kernel. A lot of hardware drivers were (are) written by the hardware (chip) manufacturers and then abandoned.

Cool tool! I wrote something for reverse-engineering code, as a consultant years ago. They had a radio module but the manufacturer had lost the source code.

So the tool was called Golem. It had tables for defining opcode to assembler pattern matching, that could be written for any machine (instead of just the one I was cracking).

It worked iteratively. You ran it over the binary once, it produced arbitrary labels from jump-points. You could annotate that output by changing the labels to something human-readable (e.g. Loop-back, Main, TimerISR etc) and add comments.

The next iteration would read that back in to build a symbol table, rescan the binary and re-output. But this time it would understand that the symbols were always on opcode boundaries, distinguish data table from code entry points (because you marked them) etc. So it would do a better job of staying in sync with the code.

Once I was done with that project (and had re-compilable source for the radio module) I put it away and never thought of it again.

I’m running OpenWRT and the Archer c7 is on the list of supported devices. I’d say give it a try.

This is indeed a cool tool! I've used it before when forensically analyzing a cell phone, and found interesting things. For example, I found that a web browser had cached the unencrypted bytes from an HTTP message. Binwalk identified the gzip header's magic number (1f 8b), and after decompression there were interesting results.

Another cool tool I learned about recently is signsrch. It's more for reverse engineering binaries of software that implements encryption of some type. It'll find signatures in the binaries of these encryption methods, giving you a place to look when, for example, reverse engineering a file format that you suspect is encrypted in some way.

https://www.oreilly.com/library/view/learning-malware-analys...

Did I read the blog wrong, or was the stock firmware too based on a OpenWRT kernel?

That would be pretty hilarious if it was true.