Re: Think You're A Programmer? Think Again.

Farley Flud <ff@linux.rocks> wrote at 15:21 this Saturday (GMT):

Any TRUE programmer can also program in reverse, i.e. de-program.
>
Let's see if you can assist the global effort in documenting the
xz-backdoor.
>
GNU/Linux has the absolute best tool for the job: Ghidra.
>
https://ghidra-sre.org/
>
I have posted an image of the xv-backdoor loaded into ghidra
and analyzed:
>
https://i.postimg.cc/NsrmMvDv/xz-backdoor.png
>
The left panel shows the dissassembled code and the right shows
the corresponding de-compile.
>
Notice the match:
>
xor edi, edi
mov esi, 0x12
mov edx, 0x46
mov ecx, 0x02
CALL .Llzma_decoder_end.1  <==> iVar4 = .Llzma_decoder_end.1(0, 0x12, 0x46, 2);
>
TEST EAX, EAX
JZ LAB_00100606  <==> if (iVar4 == 0) {
>
Ghidra is fucking fantastic!
>
Unfortunately, I will not be attempting to document the backdoor.
To do so would entail first learning thoroughly the functions of
sshd and I am not at all interested in network programming.
>
Yes, sshd.  Did you think that the xz-backoor was about compression/
decompression?  Ha, ha, ha, ha, ha, ha, ha, ha, ha!
>
Think again.

I'm not a security expert, nor do I claim to be. The only time I've
touched ghidra was to mod a GBA game, but I never deleted it from my
desktop.
--
user <candycane> is generated from /dev/urandom