Around 12:00 GMT March 16, 2013, a distributed denial of service (DDoS) attack took offline both the spamhaus.org website and a portion of its e-mail services. SpamHaus was able to restore connectivity by March 18; however, SpamHaus is still weathering a massive, ongoing DDoS attack. The DDoS attacks have also had less severe but measurable consequences for the Composite Block List (CBL) as well as Project Honey Pot.
The attackers appear to have hijacked at least one of SpamHaus’ IP addresses via a maliciously announced BGP route and subsequently used a Domain Name System (DNS) server at the IP to return a positive result for every SpamHaus Domain Name System-based Block List (DNSBL) query. This caused all SpamHaus customers querying the rogue nameserver to erroneously drop good connections.