[CentOS-mirror] DDOS Attacks

Wed Aug 6 03:00:14 UTC 2014
Ricardo David Carrillo Sanchez <dominus.ceo at gmail.com>

Which tool did you use to get this output, perhaps it is not an attack  or do you have any kind of log to complement the output?—
Sent from My mobile device

On Tue, Aug 5, 2014 at 8:01 PM, Paul Stewart <pstewart at nexicomgroup.net>

> Thanks for the input.  This is new and just started today - it’s
> definitely an attack towards the server.  We are seeing the exact same
> attacks now against other servers but all day until about an hour ago it
> was the CentOS mirror specifically (which may have just been dumb luck).
> If nobody else is seeing anything like this then that’s good news - the
> closest in the past that we have seen is Chinese IP addresses downloading
> the same ISO images over and over.  This attack is seeing the source IP
> addresses worldwide (about 175 of them on average) indicating it’s botnet
> related likely.
> The attacks look like this:
> Type:        TCP SYN Misuse
> ID:          198828
> Resource:    xx.xxx.xx.2/32 Other
> Router:      Not Applicable
> Interface:   Not Applicable
> Severity:    high
> Impact:      662.58 Mbps/93.27 Kpps
> Started:     2014-08-05 23:55:40
> Ended:       2014-08-06 00:02:41
> Link rate:   93.27 Kpps, 186.530000% of 50.00 Kpps
> Protocol:    tcp
> Flags:       S
> Router:      xx.xx.xxx.59 (core1.xxxxxxxxx)
>              Input If.: 694 (xe-4/2/0.101)
>              Output If.: 604 (xe-2/3/0.0)
> URL:         https://xxxxxxxxxxxxxxxxxxxxxxxxxxx
> Thanks,
> Paul
> On 2014-08-05, 7:24 PM, "Anssi Johansson" <centos at miuku.net> wrote:
>>6.8.2014 1.59, Paul Stewart kirjoitti:
>>> Hi there…
>>> Today, we started getting hit with DDOS attacks specifically against our
>>> CentOS mirror.  Has anyone else seen this behavior before?
>>> These are TCP SYN and TCP RST misuse type attacks.
>>I don't run a mirror myself, but please note that what you're seeing
>>might be simply yum-plugin-fastestmirror doing what's it's supposed to
>>do. yum-plugin-fastestmirror determines the closest mirror by opening a
>>TCP connection to each mirror and then closing the connection
>>immediately. The time spent is measured, and the fastest mirror as
>>determined by this process gets selected.
>>CentOS-mirror mailing list
>>CentOS-mirror at centos.org
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> CentOS-mirror at centos.org
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