Back to home page

DOS ain't dead

Forum index page

Log in | Register

Search:  
Back to the forum
Board view  Mix view

speedsys.exe packed (Users)

posted by ecm Homepage E-mail, Düsseldorf, Germany, 13.04.2025, 14:25

> You mentioned that the executable that you've used is
> packed:
>
> > Now I'd like to know how to patch (skip)
> > this IO access at runtime by some TSR or
> > loader as I cannot patch the EXE coz it's
> > encrypted or packed by unknown exe
> > packer... Speedsys checks for V86 mode and
> > complains about it (can run but very
> > limitest tests available)
>
> If it's created by
> speedin1
> then it's just a DOS/EXE UPX with the "UPX!" signature (offset 55h) and the
> depacked size (offset 6Bh) hacked. You can restore the signature manually
> then adjust the checksum (offset 6Fh).
> UPXDUMP can tell you
> the current and expected checksum. After hacking the size and checksum to
> mirror the speedin1 modification I was able to unpack an executable using
> upx-ucl -d test.exe, despite the wrong size field.
Hmm, the speedsys.exe file in https://www.philscomputerlab.com/dos-benchmark-pack.html isn't packed in this way.

---
l

Post reply
 

Complete thread:

Back to the forum
Board view  Mix view
22477 Postings in 2087 Threads, 400 registered users, 120 users online (1 registered, 119 guests)
DOS ain't dead | Admin contact
RSS Feed
powered by my little forum