I found a DOS executable file with no executable code? \ VOGONS

I found a DOS executable file with no executable code?

Topic actions

First post, by firedihm

Posted on 2025-06-28, 20:03

firedihm Offline

Rank Newbie

Rank: Newbie
Posts: 1
Joined: 2025-06-28, 19:21

Hello everyone.

I was attempting to translate an old DOS game. I found where game stores it's strings, but the file is very bizzare: it has a header of an executable file, but there's no executable code.

Could it be that I'm dealing with compression of some sort?

I assume the file's text section is supposed to begin at

10x200

based on

1[0x08] * 0x10

The attachment screen.png is no longer available

Reply 1 of 3, by mkarcher

Posted on 2025-06-28, 20:12

mkarcher Offline

Rank l33t

Rank: l33t
Posts: 3317
Joined: 2019-01-19, 16:29
Location: Germany

I don't think you are looking at compression, instead, this seems to be a data-only file with a MZ-type header to make it loadable by some overlay management system. One indication that this file is not meant to be executed by the user, but loaded by an overlay system is the overlay number in the MZ header being nonzero. Also, the file extension ".DAT" makes it quite clear that this file is not necessarily containing code.

Reply 2 of 3, by mr.cat

Posted on 2025-06-29, 11:58

mr.cat Offline

Rank Member

Rank: Member
Posts: 400
Joined: 2020-12-13, 11:56
Location: Finland

Yep...if it had compression, all those zeroes would be gone. Looks like a set of 32-bit offsets or something.
Take a look at binwalk's -E switch, it can give you some hints about where exactly the compressed parts are located in a file.

Reply 3 of 3, by igully

Posted on 2025-06-29, 18:22

igully Offline

Rank Newbie

Rank: Newbie
Posts: 44
Joined: 2024-09-07, 19:26

I 've used to collect binary computer virii samples back in the day.

Many collectors used what we called "tampon files" that were used as inert hosts candidates to purposely infect and thus get a clean, isolated copy of the virus, without the executable program that was the original victim it attached to.

Go to top of page Go to top of page

Back to DOS