alt Hacker NewsIf you read the article, the OP points out that static analysis for this platform is not supported in Ghidra.
Also, reading between the lines, I think it's safe to assume the author did dump the flash.
> Using the strings command on the firmware dump reveals a lot of interesting details about the webserver itself, but nothing obvious hints us to the password.
The author is referring to limitations in analysing banking:
> Ghidra supports the 8051 architecture but not code banking.
Usually in these ISAs an I/O port or a register sets the bank number, so any processor module should be able to resolve concrete banked references. But you still need to know what that register holds in various code paths, which are likely dynamically computing those values.
No tooling can give this out-of-the-box, as it relies on knowing the concrete initial state of the system (i.e. memory and register contents), and knowing what to return when hooking into I/O accesses.
Once these are known, we can leverage the built-in pcode emulator and run it with this state. It seems nowadays Ghidra has some built-in support for Z3, but I personally never used it, so I'm not sure how viable it is for symbolic execution. Regardless, with either approach, we would now have concrete banked code references being resolved, and could script some auto annotation of the disassembly with these references. These would be equivalent to what the author gathered from the logic analyzer trace.
A pure static analysis approach seems to suggest one would manually brute-force through all possible bank numbers at any given code path, which I guess is only viable if you have the time for that.