If you change a file like a .mp3 one, let's say, to a .123 one, so that it can't be opened, is there any way to recover the orginal file?
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If you change a file like a .mp3 one, let's say, to a .123 one, so that it can't be opened, is there any way to recover the orginal file?
Renaming it back to the original extension?
Erm.. perhaps I've misunderstood the question but if you've simply renamed a file extension from, say, .aaa to .bbb, changing it back to .aaa will return it to its original file association group.
the association is with extension, not with the file. You can change how many time you want, just returning to correct one before use it
It is possible to corrupt a file like that though. So, make sure you have a backup...
Say you have a .exe and then rename it .123
Since .123 is actually a lotus spreadsheet... someone can open it with a spreadsheet ap.
Lotus won't be able to understand it and will ask the user to convert it.
If they save after the conversion... and then you rename it back .exe, it will be corrupt.
I've played around a bit just seeing what would happen if I did this, or that...
I get bored sometimes...
So, if you rename a file extention, then don't do anything to it again before renaming it back... it will be fine.
I know I have to do that sometimes when sending emails.
Since everyone started stripping .zip files (thanks to recent viruses) I can rename the file to a .zif and just tell whoever I'm mailing to rename it back to .zip.
I do that too, since our mail servers(or firewall) strip the *.mpg, *.avi, *.zip, etc. It was the most obvious thing to do, in my mind. Even had to make a little text file explaing to my jughead friends how to get the file back to the original extension to play it or what not. I usually rename to .aaa or just no extension at all. It's kind of annoying to do that all the time, but at least the files get through this way.
Phish:
Thanks for telling the virus authors in public how to socially engineer my (L)users and bypass my firewall mail protection..... ;) They didn't get the "don't put the password into password protected zips" bit of advice so I had to block them, (I could tell by the number of dumb questions). :rolleyes:Quote:
Since everyone started stripping .zip files (thanks to recent viruses) I can rename the file to a .zif and just tell whoever I'm mailing to rename it back to .zip.
What you don't want to be doing is rename an .exe file to something like .txt. I mean, you could want to - but it would obviously be a large frigging text file. Point is, MS decided it's not a big issue that CMD.EXE executes any file that is an executable, even if it doesn't have the executable extension. Unfortunately this poses a greater security risk then most care to admit...
As for your question... do you mean can somebody realize what file it is, originally? They could probably break it down using a hex editor and try to do a look-up on the header of the file, in order to detect what it could be. MP3s usually have the title in the first few bytes, .avi containst the line '.avi' close to the top, and .mpg might require a bit more to find - but nothing difficult. Of course for different files there are different situations...
If you only meant the file extension change, I guess you should also read up on file systems and their allocation tables, in order to get maybe a better understanding of what exactly filenames are and everything related.
TS you cant tell me you allow .zif files threw your firewall. i know better than that.
TheFueley you could always uu encode it and send it as a txt attachment then tell the recipiant to change the extention of the attachment to uue. the icon will instantly change to that of a zip file and winzip will be able to open it and what you've sent will be inside the zip.
i think what he is asking, is if you change the filename extention to .123 for example, is there a way to tell WHAT the original extention was?? in otherwords, if i change matrix.zip to matrix.mpg -
obviously windows media player wont open it, but is there a way to discover what it was originally??? is that what you were asking??
It turns out, there is way to do what CybertecOne was asking. Under *NIX, just type file filename. Yes, there is a command called file. I know it's a bad name for the command, but I didn't write it. Under Windows you have two choices:
1. Download the zip file attached below. It contains a Windows port of the file command. No, it's not a virus. No, I don't have the source code. And no, I don't know where I got it from. Download it or not, it's your choice.
2. Download filealyzer from PepiMK software (the same guy(s) that make(s) Spybot S&D). Use this link to get there: http://www.safer-networking.org/en/f...zer/index.html
Cheers,
cgkanchi
PS: Forgive the smart-ass nature of this post, I'm just having a bad day.
Hey Hey,
Since cgkanchi forgot to add the download link at the end of his post.. Here's the page you can grab the file from -- http://gnuwin32.sourceforge.net/packages/file.htm. Check out more of the gnuwin32 files if you are interested in *nix software ported to Windows.. it's often quite handy to have around.
Peace,
HT
hey, i wasnt asking, just trying to decypher what the original post was..... but thanks anyways... seems like a useful tool.
Otoh if i change matrix.mpg to matrix.zip, then drop it to wmp, it will open it. Yes, it will complain for the first time for the unusual extension, but if i tell it that it's ok, it will happily open the .zip file, detect that it is actually an .mpg file, then treat it as one. You guys should know better than me about this... :)Quote:
in otherwords, if i change matrix.zip to matrix.mpg - obviously windows media player wont open it,
Peace always,
<jdenny>
thats because its not really a zip file and is INDEED an mpg file......
furthermore,
that is the only way i thought possible of trying to work out what type of file it is... (that is of course without looking at the hex etc) was to trial and error the file into the right program, which is why that tool that cgkanchi submitted looks interesting ...
Any ZIP file start with the letters PK (just open in notepad or better yet a hex-editor)
PK stands for Phil Katz, the origional "inventor" of the PKZIP algorithm..
I don't know about other file extensions but I changed .dat extension(VCD format ) to .mpg and voila i can still watch the movie but when i changed it to .123 and then burned it on CD as data and after copying back to comp changed it back to .dat ,..... it was corrupt and invalid data format even with .dat ext.
phew.... it accidentaly happened (in second case) but it did corrupted file.
I never got it why the VCD/SVCD formats convert to .dat, because the files are and will always remain MPGs. Probably some backward compatibility thing? Anyway in your case I believe the burning software might've 'tweaked' your file for a bit if the extension was recognized in some way. You could do more trial and error starting out from .txt renamed to .exe or something.. The other way aswell... and see what you get.Quote:
Originally posted here by rider_royal
I don't know about other file extensions but I changed .dat extension(VCD format ) to .mpg and voila i can still watch the movie
Someone should port it to windows.Quote:
It turns out, there is way to do what CybertecOne was asking. Under *NIX, just type file filename. Yes, there is a command called file. I know it's a bad name for the command, but I didn't write it.
I use it all the time, especially with some of them mp3 download sites, they rename mp3s or zips to anything from .xls to .doc to .whatever.
A quick 'file' and a renaming and i am happy
ehm.. you kinda missed a part of this thread |gridley|
http://gnuwin32.sourceforge.net/packages/file.htm
posted by HTRegz after cgkanchi allready attached (an older version of) the app in a previous post..
Indeed I missed it, thanks for pointing me too it.
Tedob1,
I tried what you suggested with the uuencode. Apparantly our servers strip .uue and .txt files. I tried it both ways. Here's a sample of what I got emailed back to me.
that was for the .uue file, this is what i got for the .txt file i sentCode:Content violation found in email message.
From:
To:
File(s): tshirt-folding.mpeg
Matching filename: *tshirt*folding*.mp*
These were just test files, to see if i could get through. I guess the best way, at least on my end, is to send with no extension and tell them what to change it to.Code:Content violation found in email message.
From:
To:
File(s): mastercard.txt
Matching filename: mastercard*.*
just a thought, will some servers allow files to be transfered without an extention... purely for the fact it could be anything??
If it had no extenstion, it would be an useless file !Quote:
will some servers allow files to be transfered without an extention...
i think you should read the post above mine copyright... and i ask again, will you be able to transfer if you removed the file extention and left it blank.... on the fact it could be any file...??
Not completely sure why, but if I change a .zip file to .txt file and email it to somebody. Our Groupwise email server does something to the file that corrupts it. I usually just change the .zip's to .jpg or .gif without any problems though.
so, what you are saying is that just about any binary and script on my tux box is useless ??Quote:
when u send attached files that can read by smtp "scan" engine as text, such as a .txt file the process its diferent from a image file. Maybe the scan engine corrupts the file trying to "scan" it.
btw if u send to zip file as a .txt, you deserve that it is destroyed... :)
So the point is, to answer the original question:
Yes, files can get corrupted when you change the extension. Make sure to use an extension that email scanners won't mess with and still let through. (if your intension of changing the extension is to get through the email scanners)
how would you rename the file extention in the first place in windows xp, i used to do it in win 98 through a command prompt but now it doesnt work in XP
you could do it via the command prompt
but easier would be to disable some of Windows explorers worst features..
- select Start | Settings | Control Panels | Folder Options
- select the View tab
- check "show hidden files and folders"
- UNcheck "hide file extensions for known file types"
- Click OK to finish
and then just rename ;)
thanks man <3