Unrecognized sequence of bytes

Question

I have this piece of code:

.text:00537FDE                 push    offset a3Rrrrrrrrrrrrr ; "3L+ÐÐÐÐÐÐÐÐÐÐÐÐÐ+ÐÐÐÐÐÐÐÐÐÐÐÐÐÐÐøû9\n"
.text:00537FE3                 call    sub_5606A0

Where offset a3Rrrrrrrrrrrrr is:

.text:005379B0 a3Rrrrrrrrrrrrr db '3L+ÐÐÐÐÐÐÐÐÐÐÐÐÐ+ÐÐÐÐÐÐÐÐÐÐÐÐÐÐÐøû9',0Ah,0

The bytes from Hex View of this string:

.text:005379B0  33 C0 C3 90 90 90 90 90  90 90 90 90 90 90 90 90  3L+ÐÐÐÐÐÐÐÐÐÐÐÐÐ
.text:005379C0  C3 90 90 90 90 90 90 90  90 90 90 90 90 90 90 90  +ÐÐÐÐÐÐÐÐÐÐÐÐÐÐÐ
.text:005379D0  E8 EB 39 0A 00 68 C0 79  53 00 68 80 56 6A 00 6A  øû9.hLyS.hÀVj.j

And sub_5606A0:

.text:005606A0 sub_5606A0      proc near               ; CODE XREF: WinMain(x,x,x,x)+223p
.text:005606A0
.text:005606A0 arg_0           = dword ptr  4
.text:005606A0
.text:005606A0                 mov     eax, [esp+arg_0]
.text:005606A4                 mov     dword_8478CC, eax
.text:005606A9                 retn
.text:005606A9 sub_5606A0      endp

What can this encoded string mean?

.text:005379B0 a3Rrrrrrrrrrrrr db '3L+ÐÐÐÐÐÐÐÐÐÐÐÐÐ+ÐÐÐÐÐÐÐÐÐÐÐÐÐÐÐøû9',0Ah,0

Thanks in advance!

Answer 1

The Sequence of Bytes do not represent a string

please take note of the first 3 bytes 0x33,0xc0,0xc3

These are opcodes for xor eax,eax , retn basically return 0; in c / c++

0:000> eb . 33 c0 c3
0:000> u . l2
ntdll!LdrpDoDebuggerBreak+0x2c:
777a05a6 33c0            xor     eax,eax
777a05a8 c3              ret
0:000>   

this is probably a chunk of a function which has many return 0; statements

like if(!a)retun 0; do b= blah(); if(!b) return0; .......

here the compiler might have recognized the repetition
and must have split the part into a seperate piece/chunk as part of optimization.

that said 0x90 aka NOP is shown as some kind of D

.text:005379B0  33 C0 C3 90 90 90 90 90  90 90 90 90 90 90 90 90  3L+ÐÐÐÐÐÐÐÐÐÐÐÐÐ

which indicates it is not probably a normal english locale encoding