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57 lines
2.1 KiB
57 lines
2.1 KiB
Spam
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====
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This tunnel implements Ethernet/IP over spam mails. Before the data is going
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out it is encoded to look like an ordinary spam mail.
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A friend told me about a "Network Protocols and Architectures" lecture,
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a course given at TU-Berlin, featuring this task as a "cristmas homework",
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showing a slide from Dan Kaminsky talking about this idea for bypassing the
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Great Firewall of China.
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Installation and requirements
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=============================
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You need either an e-mail account reachable via IMAP or a MX record pointing
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to your server. Configuration is done via conf.py. Currently the other side
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of the connection needs to be specified as 'mailTo' (see conf.py).
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How it works
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============
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Each outgoing network packet is encoded to text looking like spam mails. The
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encoder/decoder can easily be replaced by something else but all clients need
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to have the same dictionary/language. The packet is split up into 3bit entities
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and then decoded into words using the current dictionary. An Ethernet packet
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(mtu 1500 bytes) is blown up to 74kb of spam text.
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Every packet is currently mailed to the configured 'mailTo' address. Incoming
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messages are fetched via imap or, if running as an smtpd, directly parsed on
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delivery.
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Multiple Clients
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================
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Having support for multiple clients would be an awesome thing! Currently only
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point to point connections are available. The problem with having multiple
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clients is, that somehow a client needs to know where another client can be
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found. Many concepts exist to solve this problem. The straight forward approach
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of a single authorative server would work but introduces a single point of
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failure, making the network vulnerable to censorship and server failures.
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As said in the section below: This needs to be implemented. ;)
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What could be done
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==================
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* add support to send mails directly via smtp, not via a specific smtp server
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* allow the spam tunnel to run as an IP tunnel, configurable via config
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* implement support for multiple clients
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* support exchange of encoding dictionary prior to sending/receiving data
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Licensing
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=========
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Written by Sebastian Lohff <seba@seba-geek.de>
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Published under the GPLv3 or later
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