Bugtraq: Re: eSafe: Could this be exploited?

["Andreas Constantinides (MegaHz)" <megahz () megahz org>]

which version of eSafe are we talking about? 3 or 4 ?

On Sat, 2004-07-24 at 14:27, 3APA3A wrote:
> Dear Hugo van der Kooij,
>
> --Friday, July 23, 2004, 10:21:22 PM, you wrote to bugtraq () securityfocus com:
>
> HvdK> Both as NitroEngine or CVP server they will push as much of 80% to the
> HvdK> end-user before they stop a virus. Then they rely on the adding of the
> HvdK> exact URL so that URL can be blocked in all next requests.
>
> It depends on how antiviral check is actually implemented. If connection
> is  broken  immediately after signature is detected - there is no way to
> download  infected  file,  because signature will not pass to client and
> client  will  not  be  able  to  use "Range:" header to resume partially
> downloaded  file.
>
> If  antiviral  filter  checks data _after_ all data received from client
> with  20%  buffering  yes,  it's possible to bypass this check for HTTP,
> because  there  is  no  way  (at least for HTTP/1.0 and FTP) to indicate
> error to client and make him to delete partially downloaded data.
>
> You can check it, by sending EICAR with some additional data: if you can
> find  EICAR  signature  on  the  client  after  connection  is broken by
> antiviral filter you can bypass it's protection.