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birezillion
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Forgot Excel Open Password

Thu Jan 24, 2019 10:12 pm

The Excel file was sent by my colleague 3 years ago. I have some impression about the password but couldn't figure what exactly it is. Is there any way to recover it?
 
Usacomp2k3
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Re: Forgot Excel Open Password

Fri Jan 25, 2019 7:30 am

Last time I looked there were plenty of crackers available online. I've used them successfully in the past for some personal files. Not going to link any though per the forum rules. Just use a VM if you can to be on the safe side.
 
Arvald
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Re: Forgot Excel Open Password

Tue Jan 29, 2019 11:29 am

there are macro based ones that you can download.
there are also web sites you can upload to and it will either give you password or send back the cracked sheet.

Excel passwords are a simple deterrent, not security.
 
qmacpoint
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Re: Forgot Excel Open Password

Tue Jan 29, 2019 11:50 am

Couple of thoughts about this:
  • I would not advise to upload a file to a web service for cracking if the contents of the file are private to you
  • Excel-wide passwords are different than Worksheet-specific passwords: Worksheets can be cracked easily as they possess a weak implementation that allows for collision (i.e. a string different than the original password may allow to open the file). Macros out there would allow you break the password.
  • for Excel-wide passwords, if the document is in the old format (i.e. 'xls' used up to Excel 2003) you can google guides that provide advice on how to remove the protection forcefully by modifying hex values on the file. Proceed at your own risk.
  • If the format is from Excel 2007 onwards ('xlsx') things get super complicated. You would require to extract the hash (i.e. computed value derived from the password) from the file with a python script and then run a statistical analysis to break said hash with a GPU-based tool for processing.

Hopefully I've given enough hints for you to google these things and find what you really need, but be mindful that this requires technical expertise to pull off. There are password bruteforcers (i.e. software that attempts every character possible for the password until a match is found) which support all of the Excel formats and usually go around 20 USD and are easier to use - however use judgement and validate if they are REPUTABLE enough to use.

PS: For those who know the tools I'm talking about... hi there! :D
 
frumper15
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Re: Forgot Excel Open Password

Tue Jan 29, 2019 11:54 am

birezillion wrote:
The Excel file was sent by my colleague 3 years ago. I have some impression about the password but couldn't figure what exactly it is. Is there any way to recover it?


Can you just ask the colleague what it is?
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DragonDaddyBear
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Re: Forgot Excel Open Password

Tue Jan 29, 2019 12:25 pm

Assuming it's an XLSX and just protected (not encrypted) then file crack it open in an XML viewer and remove the password. That removes the protection. That allows you to copy-pasta into a new workbook.
 
birezillion
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Re: Forgot Excel Open Password

Mon Feb 04, 2019 10:34 pm

DragonDaddyBear wrote:
Assuming it's an XLSX and just protected (not encrypted) then file crack it open in an XML viewer and remove the password. That removes the protection. That allows you to copy-pasta into a new workbook.


no, it is an open password
 
ludi
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Re: Forgot Excel Open Password

Mon Feb 04, 2019 11:46 pm

Try opening it with a third party program or viewer. OpenOffice, for example. You could also try an online viewer like this but who knows what the third party does with the information they can (potentially) see when you do that.
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birezillion
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Re: Forgot Excel Open Password

Sun Feb 24, 2019 9:10 pm

lud1 wrote:
Try opening it with a third party program or viewer. OpenOffice, for example. You could also try an online viewer like this but who knows what the third party does with the information they can (potentially) see when you do that.


yeah, a bit worried about the online service. desktop app might be safer but slow at speed.
 
Gooery
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Re: Forgot Excel Open Password

Mon Feb 25, 2019 1:50 am

ldui wrote:
Try opening it with a third party program or viewer, you could also try an online viewer like this but who knows what the third party does with the information they can (potentially) see when you do that.

They can only crack passwords, and as for file information, that's not their concern.
 
lopis
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Re: Forgot Excel Open Password

Tue Mar 19, 2019 12:23 am

I'd recommend to recover old excel document without protection if it's possible. I'm not sure you can "crack" xlsx...

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