Active BOTNETs have been attacking the denial-of-service attacks against Word Press based sites (often used for blogs) as shared below.  

https://blog.sucuri.net/2016/02/wordpress-sites-leveraged-in-ddos-campaigns.html

We first disclosed that the WordPress pingback method was being misused to perform massive layer 7 Distributed Denial of Service (DDoS) attacks back in March 2014. The problem being that any WordPress website with the pingback feature enabled (its default setting) could be used to attack the availability of other websites. The attacks would inundate the web server with Layer 7 requests resulting in very large DDoS attacks.

If you are not familiar with the terminology, Layer 7 attacks (also known as http flood attacks) are a type DDoS attack that disrupts your server by exhausting its resources at the application layer, instead of the network layer. They do not require as many requests or as much bandwidth to cause damage; they are able to force a large consumption of memory and CPU on most PHP applications, CMSs and databases. We provide a more in depth explanation in our previous article – Analyzing Popular Layer 7 Application DDoS Attacks.

Massive Layer 7 attacks – Despite the potential reduction in value with the IP logging, attackers are still using this technique. Likely because website owners rarely check the user agent logs to derive the real IP address of visitors. For system administrators I highly recommend referring to it when performing your administrative and forensic tasks.

In a recent case we investigated, 26,000 different WordPress sites were generating a sustained rate of 10,000 to 11,000 HTTPS requests per second against one website. At some intervals, the attack would peak to almost 20,000 HTTPS requests per second. The attack started at 1pm (EST) and by midnight it was still ongoing.