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Optimizing NASM Assembler codes in Windows x86
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Topic: Optimizing NASM Assembler codes in Windows x86 (Read 8078 times)
SHITTY23
New Member
Posts: 1
Optimizing NASM Assembler codes in Windows x86
«
on:
September 04, 2022, 09:21:34 PM »
I am a novice in assembler programing, I will will appreciate if someone could review these NASM assembler code for me. Is about encoder decoder.
The encoder performs the following:
pads the shellcode with NOP opcodes so it is 4 bytes aligned
a random byte is generated for each 4 bytes of the shellcode
the 4 bytes are put in the reverse order and XORed with the XOR byte
process is repeated until the 0x9090aaaa marker is reached
For those good at NASM assembler for Microsoft Windows, please could you optimize this code? the Code is working but takes lot of time. The shellcode is a windows/meterpreter/reverse_tcp x86 from msfvenom.
Code:
[Select]
global main
; gone
; Frank
«
Last Edit: September 05, 2022, 03:02:45 PM by Frank Kotler
»
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Frank Kotler
NASM Developer
Hero Member
Posts: 2667
Country:
Re: Optimizing NASM Assembler codes in Windows x86
«
Reply #1 on:
September 05, 2022, 10:11:37 AM »
Shellcode has rather a bad reputation. Why are you using it?
Best,
Frank
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fredericopissarra
Full Member
Posts: 373
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Re: Optimizing NASM Assembler codes in Windows x86
«
Reply #2 on:
September 05, 2022, 01:02:42 PM »
Very funny how you tried to inffect somebody computers with Trojan:Script/Wacatac.Html...
To the moderator I recommend deleting this and ban the user.
PS: Decode (do not run!) the byte stream and let the antivirus do its trick...
«
Last Edit: September 05, 2022, 01:06:55 PM by fredericopissarra
»
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Frank Kotler
NASM Developer
Hero Member
Posts: 2667
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Re: Optimizing NASM Assembler codes in Windows x86
«
Reply #3 on:
September 05, 2022, 02:18:58 PM »
Thank you, Fred!
I hadn't decoded decoded his shellcode, but would have before I ran it.
He's gone in just a second.
Best,
Frank
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tysonprogrammer
Jr. Member
Posts: 22
Country:
C# application developer attempting assembly.
Re: Optimizing NASM Assembler codes in Windows x86
«
Reply #4 on:
September 06, 2022, 09:56:50 PM »
I chuckled at the username and it was a bit suspicious because of it
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Elawig57
Jr. Member
Posts: 5
Re: Optimizing NASM Assembler codes in Windows x86
«
Reply #5 on:
January 24, 2023, 06:06:43 AM »
Hello,
It looks like the code you've provided
Redacted by moderator!
«
Last Edit: January 25, 2023, 04:06:23 AM by Frank Kotler
»
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Frank Kotler
NASM Developer
Hero Member
Posts: 2667
Country:
Re: Optimizing NASM Assembler codes in Windows x86
«
Reply #6 on:
January 24, 2023, 09:17:03 AM »
The person with the questionable name has been banned from the forum.
If you do not want to join him, do not discus malware here!
Seriously,
Frank
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Optimizing NASM Assembler codes in Windows x86