InDuLgEo's InDuLgEo V3-B — The DOS Intro Challenge

Author:
InDuLgEo

Language:
Assembler

Upload:
2025-07-01 18:16

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Platform:
Windows

Difficulty:
3.0

Quality:
4.0

Arch:
other

Downloads:
26

Size:
1.97 KB

Writeups:
3

Comments:
10

Description

─────────────────────────────────────────────── InDuLgEo V3-B — The DOS Intro Challenge — InDuLgEo / AoRE ☠️🧬 [2025] ─────────────────────────────────────────────── 🧠 Challenge: Your mission is to explore this .COM intro, understand how the strings are displayed, and create your own modified version that displays your personal message. 🎯 Objective: - Reverse the original message logic - Replace it with your own custom strings - Maintain full functionality: fire effect & music 💻 Target Platform: - MS-DOS - Windows XP (SP2 or earlier) - DOSBox 0.74+ (recommended for modern systems) 📎 Notes: - File is ~2 KB and runs natively - Entry point is standard 0100h (COM format) - No external files or dependencies 🎨 Extra Style Points: - Keep the fire running smoothly - Sync your message with the screen rhythm - Sign your version with your scene handle To prove you've completed the challenge: → Share your custom .COM with your message → Include screenshots or writeups on crackmes.one → Tag your version: InDuLgEo_V3-B_[YourHandle] ─────────────────────────────────────────────── Enjoy the ride... oldschool style 🔥 ───────────────────────────────────────────────

Comments (10)
Writeups (3)

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nightxyz on 2025-07-03 08:49: There are 3 sections in the program. In the first section, there is a blue image with a waving shape. After that, there is a fire effect in the second section. In the last section, there is a fractal but it is not an animated image. In the top rows, the messages are fixed and the phone ringing sound is heard intermittently. In the second section with the fire effect, is it to print text on the screen or to change the messages on the last screen that the programmer printed?

InDuLgEo on 2025-07-03 12:38: Reply to nightxyz: Thanks for your interest in the .COM crackme 😊 The fire effect is just an intro transition. The actual challenge is in the third section — the fractal is static, and your task is to patch the final text shown at the bottom without breaking any visuals or the effect sequence. So yes, the goal is to modify the bottom strings shown in the final screen (fractal section) while keeping everything else intact. You don't need to animate or change the fractal — only modify the final message (e.g., "Reverse by ...") to show your custom tag or nickname. Good luck! — InDuLgEo / AoRE ☠️🧬

nightxyz on 2025-07-04 08:47: @Elvis, author want patched file also but i could only uploaded pdf file. Can you combine my first uploaded COM file with this pdf file ?

InDuLgEo on 2025-07-04 15:55: 🔥 @nightxyz I’ve carefully reviewed your .pdf solution, and I must say: ✅ Everything is spot on! 🧠 Great job analyzing the decryption logic and patching routine with the XOR 0x18. I really liked how you explained each step, even using DEBUG inside DOSBox — that’s true .COM old-school spirit. 👾 The attention to details like INT 21h, AH=09h and the use of $ as a string terminator shows full understanding of the program's flow. 🔧 Not including the patched .COM isn't a big deal — your .pdf is clear, well-structured, and serves perfectly as a documented solution. Well done on your clean and technical approach. — InDuLgEo / AoRE ☠️🧬

nightxyz on 2025-07-04 17:25: @InDuLgEo Thank you. I have used Softice, Sourcer, Turbo Debugger, Debug at old good DOS days. If i see anything related to DOS, it attracts me. At first, i only uploaded COM file but site manager rejected it because it doesn't have any description. Later, i uploaded solution but system only allows one file uploading. I wish I had compressed the 2 files into one and uploaded them. I asked the moderator but he didn't. After I uploaded the file, the system didn't allow me to upload the file again. I will try to upload again.

InDuLgEo on 2025-07-04 17:35: 🔥 @nightxyz Thanks for the kind reply, and your dedication really shines through. You’re clearly from the oldschool era — SoftICE, Turbo Debugger... that’s the real legacy. 📁 No worries about the .COM file — your explanation in the PDF was already clean and complete. Even your attention to the system’s upload limitations shows you care about presenting things right. 🧠 If you do get a chance to re-upload both files together, great. If not — your work still speaks for itself, loud and clear. — InDuLgEo / AoRE ☠️🧬 “Reverse with honor or not at all.” 🔥 Scene is alive — because minds like yours still play the game right.

InDuLgEo on 2025-07-06 10:22: 🔥 @Ja4V8s28Ck Absolutely brilliant work — your solution captures the true spirit of this .COM challenge. ✅ You dissected the unpacking logic with precision ✅ Used DEBUG like a true oldschooler ✅ Reconstructed the XOR routine flawlessly ✅ Preserved every visual effect while customizing your final message Your Python script to automate the patching process was a clever touch, and your attention to the string layout (with $ terminators intact!) shows deep understanding of DOS internals. 💾 The re-XOR with 0x18 and proper byte alignment — pure scene craftsmanship. And I’ve tested your patched .COM — it works flawlessly. Exactly as intended: clean, intact, and with your own message shining at the end. 👏 Massive respect for taking the time to understand and modify, not just "crack". The scene needs more minds like yours. — InDuLgEo / AoRE ☠️🧬 “Reverse with honor or not at all.”

Ja4V8s28Ck on 2025-07-06 11:03: @InDuLgEo, Thanks for your kind words, it's really motivating. I'm not a old schooler to be honest, I have only used DOS for playing Super Mario, So I have limited knowledge in using and debugging programs in DOS. Unpacking the .COM program was difficult as I couldn't find proper sources in debugging DOS file nor unpacking it. That's why I presented this writeup so that everyone can learn.

InDuLgEo on 2025-07-06 11:21: 🔥 @Ja4V8s28Ck Man, that makes your work even more impressive. Coming from playing Super Mario on DOS to unpacking a .COM file, tracing execution and dropping a clean writeup? That’s the kind of evolution we love to see. You didn’t just solve it — you made it easier for others to follow. That’s how legends start. Big props from me and the whole AoRE vibe. Keep pushing — the scene needs more minds like yours. — InDuLgEo / AoRE ☠️🧬

Ja4V8s28Ck on 2025-07-06 11:44: @InDuLgEo Thanks you so much!!!. But I don't deserve all these.

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Solution by nightxyz on 2025-07-04 08:43:

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Solution by Ja4V8s28Ck on 2025-07-05 16:40:

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Solution by sa2304 on 2025-07-30 13:09:
Solution described in solution.txt. InDuLgEo_V3-B_sa2304.png is a screenshot of cracked program. InDuLgEo_V3-B_sa2304.CoM is the cracked program. cracked-by.txt holds text that replaced original strings.

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