[EMAIL PROTECTED]:
"Craig Southeren" <[EMAIL PROTECTED]>:
> My Apache web server is generating the several of the following messages per
> week in the error_log file:
> error:0406406F:rsa routines:RSA_EAY_PRIVATE_DECRYPT:sslv3 rollback attack
[...]
> Is this something I should be worried about, or is it benign?
This error message means that a client connected with SSL version 2,
but used specially formatted RSA padding that has the defined meaning
that the client really supports SSL version 3. This special padding
for SSL 2 compatible "ClientHello" messages was invented in order to
prevent attackers from forcing server and client to use the SSL 2
protocol (which has several weaknesses) when both support SSL 3 or
later. (The first message is usually done in SSL-2 style, but the
real version number supported by the client is included in the
message, so that the server can switch to SSL 3 or TLS 1 in its
response.)
Probably it's not really an attacker, but a broken client. I'd guess
that someone switched SSL 3 off in his browser's configuration and
forgot to switch it on again, and that that browser incorrectly uses
special padding even though SSL 3 is disabled. I don't know if
there are really browsers with such a bug, but it would be a
plausible explanation for your observation.
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