An increase in distributed denial of service (DDoS) attacks from the Bitcoin extortionist group DD4BC has been logged in recent months: Since April 2015, the team identified 114 DD4BC attacks, including more aggressive measures that target brand reputation through social media.
According to a report from Akamai’s Prolexic Security Engineering & Research Team (PLXsert), the DD4BC group has been responsible for a large number of Bitcoin extortion campaigns dating back to 2014. In the past year, the group expanded its extortion and DDoS campaigns to target a wider array of business sectors—including financial services, media and entertainment, online gaming and retailers.
The group’s historical MO goes like this: The group uses email to inform its target that a low-level DDoS attack will be launched against the victim’s website. The group would then demand a Bitcoin ransom to protect the company from a larger DDoS attack designed to make its website inaccessible. But from June through July 2015, the attacks increased from low-level to more than 20 Gbps in some cases.
“DD4BC has been using the threat of DDoS attacks to secure Bitcoin payments from its victims for protection against future attacks,” said Stuart Scholly, Senior Vice President & General Manager, Security Division at Akamai. “The latest attacks—focused primarily on the financial service industry—involved new strategies and tactics intended to harass, extort and ultimately embarrass the victim publically.”
According to PLXsert, DD4BC recently threatened to expose targeted organizations via social media, adding to the damage caused by the DDoS attack itself. The goal apparently is to garner more attention for the group’s ability to create service disruptions by publicly embarrassing the target and tarnishing the company's reputation through these wide-reaching channels.
The group’s methodology typically includes use of multi-vector DDoS attack campaigns, revisiting former targets and also incorporating Layer 7 DDoS in multi-vector attacks, specifically concentrating on the WordPress pingback vulnerability. This vulnerability is exploited to repeatedly send reflected GET requests to the target to overload the website. Akamai researchers have seen this attack method incorporated into DDoS booter suite frameworks.
The average bandwidth of the attacks in the last year stands at 13.34Gbps, with the largest DDoS attack reported at 56.2Gbps.
To help protect against extortionist group DD4BC, and subsequent DDoS attacks, Akamai recommends that companies deploy anomaly- and signature-based DDoS detection methods to identify attacks before a website becomes unavailable to users; distribute resources to increase resiliency and avoid single points of failure due to an attack; and implement Layer 7 DDoS mitigation appliances on the network in strategic locations to reduce the threat for critical application servers.