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BeMy Friend
Asked: 2014-10-25 10:59:40 +0800 CST

Help decoding Base64 using base64 -d

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**** This post links to Windows-Based malware executables!!! DO NOT EXECUTE DECODED SAMPLE ****

I hope I can post this here without having it pulled down.

I have 2 seemingly identical base64 encoded files. The first I copied down manually. The second was pulled down via a script. I used cmp to try to find any differences. I do not see any differences in the file... EXCEPT....

The file that I copied manually adds the base64 encoded text on over 1200 lines. The file that was pulled down via the script adds the base64 text on only 1 line.

When I run the base64 -d command against the file I created manually, I get the decoded text into an archive file

When I run the base64 -d command against the file created by the script, I get this error:
base64: invalid input

Here is the base64 encoded text on 1 line (saved as: Note_3316_copy): http://pastebin.com/Qs35MkS1

Here is the base64 encoded text on 1200 lines (saved as: order_id): http://pastebin.com/H3BNcQdf

This code works on the 1200 lines of code:

base64 -d order_id > order_id3.zip

This code DOES NOT work on the 1 line of code

base64 -d Note_3316_copy > note.zip

Can anyone see why this is not working?

command-line

1 Answers

  1. The 1-liner is not an actual one-liner, but contains escaped characters (a representative sample):

    hQ0MjO4DGWN\/Czoj8IR\/LX1z8\ne+M

    The \ are escaped, as is the newline (\n). That's what's causing the error, I'd guess. Fix your script.

    $ curl 'http://pastebin.com/raw.php?i=Qs35MkS1' -s | sed 's/\n//g;s;\\;;g' | base64 -d > blah.zip
$ curl 'http://pastebin.com/raw.php?i=Qs35MkS1' -s | base64 -d > blah.zip
base64: invalid input
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