Attackers don’t just utilize old, unpatched vulnerabilities, they also exploit recent disclosures at impressive rates. This year we witnessed two worldwide events that highlight the evolution and speed with which attackers will weaponize a vulnerability: Memcache and Druppalgeddon.
Memcached DDoS Attacks
In late February, Radware’s Threat Detection Network signaled an increase in activity on UDP port 11211. At the same time, several organizations began alerting to the same trend of attackers abusing Memcached servers for amplified attacks. A Memcached amplified DDoS attack makes use of legitimate third-party Memcached servers to send spoofed attack traffic to a targeted victim. Memcached, like other UDP-based services (SSDP, DNS and NTP), are Internet servers that do not have native authentication and are therefore hijacked to launch amplified attacks against their victims. The Memcached protocol was never intended to be exposed to the Internet and thus did not have sufficient security controls in place. Because of this exposure, attackers are able to abuse Memcached UDP port 11211 for reflective, volumetric DDoS attacks.
On February 27, Memcached version 1.5.6 was released which noted that UDP port 11211 was exposed and fixed the issue by disabling the UDP protocol by default. The following day, before the update could be applied, attackers leveraged this new attack vector to launch the world’s largest DDoS attack, a title previously held by the Mirai botnet.
There were two main concerns with regards to the Memcached vulnerability. The first is centered around the number of exposed Memcached servers. With just under 100,000 servers and only a few thousand required to launch a 1Tbps attack, the cause for concern is great. Most organizations at this point are likely unaware that they have vulnerable Memcached servers exposed to the Internet and it takes time to block or filter this service. Memcached servers will be vulnerable for some time, allowing attackers to generate volumetric DDoS attacks with few resources.
The second concern is the time it took attackers to begin exploiting this vulnerability. The spike in activity was known for several days prior to the patch and publication of the Memcached vulnerability. Within 24 hours of publication, an attacker was able to build an amplification list of vulnerable MMemcached servers and launch the massive attack.
Adding to this threat, Defcon.pro, a notorious stresser service, quickly incorporated Memcache into their premium offerings after the disclosure. Stresser services are normally quick to utilize the newest attack vector for many reasons. The first reason being publicity. Attackers looking to purchase DDoS-as-a-service will search for a platform offering the latest vectors. Including them in a service shows demand for the latest vectors. In addition, an operator might include the Memcache DDoS-as-a-service so they can provide their users with more power. A stresser service offering a Memcache DDoS-as-a-service will likely also attract more customers who are looking for volume and once again plays into marketing and availability.
DDoS-as-a-service operators are running a business and are currently evolving at rapid rates to keep up with demand. Oftentimes, these operators are using the public attention created by news coverage similar to extortionists. Similarly, ransom denial-of-service (RDoS) operators are quick to threaten the use of new tools due to the risks they pose. DDoS-as-a-service will do the same, but once the threat is mitigated by security experts, cyber criminals will look for newer vectors to incorporate into their latest toolkit or offerings.
This leads into the next example of Drupalgeddon campaign and how quickly hacktivists incorporated this attack vector into their toolkit for the purpose of spreading messages via defacements.
In early 2018, Radware’s Emergency Response Team (ERT) was following AnonPlus Italia, an Anonymous-affiliated group that was engaged in digital protests throughout April and May. The group–involved in political hacktivism as they targeted the Italian government–executed numerous web defacements to protest war, religion, politics and financial power while spreading a message about their social network by abusing the content management systems (CMS).
On April 20, 2018 AnonPlus Italia began a new campaign and defaced two websites to advertise their website and IRC channel. Over the next six days, AnonPlus Italia would claim responsibility for defacing 21 websites, 20 of which used the popular open-source CMS Drupal.
Prior to these attacks, on March 29, 2018, the Drupal security team released a patch for a critical remote code execution (RCE) against Drupal that allowed attackers to execute arbitrary code on unpatched servers as a result of an issue affecting multiple subsystems with default or common module configurations. Exploits for CVE-2018-7600 were posted to Github and Exploit-DB under the guise of education purposes only. The first PoC was posted to Exploit DB on April 13, 2018. On April 14, Legion B0mb3r, a member of the Bangladesh-based hacking group Err0r Squad, posted a video to YouTube demonstrating how to use this CVE-2018-7600 to deface an unpatched version of Drupal. A few days later, on April 17, a Metasploit module was also released to the public.
In May, AnonPlus Italia executed 27 more defacements, of which 19 were Drupal.
Content management systems like WordPress and Joomla are normally abused by Anonymous hacktivists to target other web servers. In this recent string of defacements, the group AnonPlus Italia is abusing misconfigured or unpatched CMS instances with remote code exploits, allowing them to upload shells and deface unmaintained websites for headline attention.
Read “Radware’s 2018 Web Application Security Report” to learn more.
Daniel Smith is an information security researcher for Radware’s Emergency Response Team. He focuses on security research and risk analysis for network and application based vulnerabilities. Daniel’s research focuses in on Denial-of-Service attacks and includes analysis of malware and botnets. As a white-hat hacker, his expertise in tools and techniques helps Radware develop signatures and mitigation attacks proactively for its customers.