Bugtraq mailing list archives
Re: base64
From: Seth Breidbart <sethb () panix com>
Date: Wed, 24 Sep 2003 13:01:21 -0400 (EDT)
See the corresponding RFC. The number of characters in a base64-coded text must be a multiply of 4. So ='s are used if there aren't enough characters and are added at the end of the text. = is not a valid character inside Base64 and an encoder should stop with an error or stops decoding.
That depends on the purpose of the decoder. If your anti-virus decoder stops there, but a virus writer knows that the decoder used by some popular mail client keeps going, then your program isn't going to detect his virus. If you're looking for something that might be hidden, then you need to decode in _every_ way that _any_ mail client (that you support) does, lest you have false negatives. Seth
Current thread:
- base64 Ilya Teterin (Sep 22)
- Re: base64 Bennett Todd (Sep 22)
- Re: base64 Erwan David (Sep 23)
- Re: base64 Birl (Sep 23)
- Re: base64 Lothar Kimmeringer (Sep 24)
- Re: base64 David Wilson (Sep 24)
- Re: base64 Earl Hood (Sep 25)
- Re: base64 Christian Vogel (Sep 25)
- Re: base64 Seth Breidbart (Sep 24)
- Re: base64 Lothar Kimmeringer (Sep 24)
- Re: base64 Alexander Ogol (Sep 23)
- Re: base64 Christian Vogel (Sep 24)
- Re: base64 David Wilson (Sep 24)
- Re: base64 der Mouse (Sep 24)
- Re: base64 Christian Vogel (Sep 24)
- Re: base64 Earl Hood (Sep 26)
- <Possible follow-ups>
- RE: base64 latte (Sep 23)
- Re: base64 Ilya Teterin (Sep 23)
- Re: base64 MightyE (Sep 24)
- Re: base64 Buck Huppmann (Sep 24)
- Re: base64 Andrew Church (Sep 25)
- Re: base64 Buck Huppmann (Sep 24)