Re: [PATCH] fix small DoS on connect() (was Re: BUG: Unusual TCP Connect() results.)

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Sun, Jun 12, 2005 at 02:32:53PM +0200, Willy Tarreau wrote:
>
> but it's not the case (although the naming is not clear). So if the remote
> end was the one which sent the SYN-ACK, it will clear its session. If it has
> been spoofed, it will ignore the RST because in turn, the SEQ will not be
> within its window.

This is what should happen:

1) client A sends SYN to server B.
2) attcker C sends spoofed SYN-ACK to client A purporting to be server B.
3) client A sends RST to server B.

The RST packet is sent by client A using its sequence numbers.  Therefore
it will pass the sequence number check on server B.

4) server B resets the connection.

Cheers,
-- 
Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmV>HI~} <[email protected]>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[Index of Archives]     [Kernel Newbies]     [Netfilter]     [Bugtraq]     [Photo]     [Stuff]     [Gimp]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Video 4 Linux]     [Linux for the blind]     [Linux Resources]
  Powered by Linux