Remote Buffer Overflow in Avirt Voice 4.0

["Donato Ferrante" <fdonato () autistici org>]

                           Donato Ferrante


Application:  Avirt Voice
              http://www.avirt.com/

Version:      4.0

Bug:          Remote Buffer Overflow

Author:       Donato Ferrante
              e-mail: fdonato () autistici org
              web:    www.autistici.org/fdonato



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1. Description
2. The bug
3. The code
4. The fix



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1. Description:
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Vendor's Description:

"Avirt Voice acts as an H.323 gateway between IP networks. It allows
users to operate H.323 applications, like Microsoft NetMeeting, Intel
Video Phone, or Netspeak Webphone, from behind a firewall.
Because Voice is a software solution, it is more easily scalable and
much less expensive than hardware alternatives."



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2. The bug:
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The program doesn't well manage the received strings on the TCP port
1080. In fact it will have a buffer overflow.



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3. The code:
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To test the vulnerability simply send to the server ( port 1080 ) a
string like:

GET aaaa[ 1113 of a ]aaaa



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4. The fix:
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Vendor was contacted.
Bug will be fixed in the next version of Avirt Voice.



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