Another Day, Another PUP

Exploit kits: Winter 2017 review

A few months have passed since our Fall 2016 review of the most common exploit kits we are seeing in our telemetry and honeypots. Today, we take another look at the current (bleak) EK scene by going over RIG, Sundown, Neutrino and Magnitude.

There haven’t been any major changes in the past little while and exploit kit-related infections remain low compared to those via malicious spam. This is in part due to the lack of fresh and reliable exploits in today’s drive-by landscape.

Pseudo-Darkleech and EITest are the most popular redirection campaigns from compromised websites. They refer to code that is injected into – for the most part – WordPress, Joomla, or Drupal websites and automatically redirects visitors to an exploit kit landing page.

Malvertising campaigns keep fuelling redirections to exploit kits as well, but can greatly vary in size and impact. The daily malverts from shady ad networks continue unchanged while the larger attacks going after top ad networks and publishers come in waves.

In the following video, we do a quick overview of those exploit kits; if you are interested in the more technical details please scroll down for additional information on each of them.

[youtube https://youtu.be/s0XmpsF4xAQ&rel=0 ]

Most used vulnerabilities

Internet Explorer

  • CVE-2016-0189
  • CVE-2014-6332
  • CVE-2013-2551

Information disclosure

  • CVE-2016-3351
  • CVE-2016-3298
  • CVE-2016-0162

Edge

  • CVE-2016-7200
  • CVE-2016-7201

Flash

  • CVE-2016-4117
  • CVE-2016-1019
  • CVE-2015-8651
  • CVE-2015-7645

Silverlight

  • CVE-2016-0034

RIG EK

RIG EK remains the most popular exploit kit at the moment used both in malvertising and compromised websites campaigns. Its primary payloads are ransomware (Cerber and CryptoShield).

The landing page structure (URL and source code) hasn’t really changed, but it is now using a pre-landing page to filter bots and other non-legitimate traffic.

Payload here: Dreambot

Gate (browser check)

Landing page

Sundown EK

Sundown EK keeps on changing its URL patterns, mainly for the Flash exploit and its payload URLs. Sundown is a lot more quiet than RIG EK and for the most part contained to some malvertising campaigns.

Payload here: VenusLocker

Landing page

Neutrino EK

Neutrino EK seems to be the weapon of choice for special malvertising attacks that are difficult to reproduce. It features its usual pre-filtering gate that includes several checks against VMs and security software.

Payload here: Neutrino bot

Filtering gate (fingerprinting)

Landing page

Magnitude EK

Magnitude EK is a very geo-aware exploit kit being restricted to Asia at the moment. It uses decoy finance or bitcoin websites with a special referer to lead to its gate.

Payload here: Cerber

IE exploit

Landing page

Wrap up

There are more exploit kits than just those mentioned in this blog, but some were not included because they were simply copycats or because we have only seen them very sporadically.

Some EKs are indeed quite difficult to reproduce without a proper setup and some previous knowledge of the various traps affiliates and traffers are putting in the way. In other cases, they may fall off the radar until a new campaign (i.e. malvertising) is put in place.

While there hasn’t been a big focus on getting newer exploits integrated, we can note that exploit kit authors are investing some time into better bot detection and evasion, essentially trying to optimize the leads they are getting.

However, we should still be aware that this situation could change as new and powerful exploits can be discovered at any time and come with a ready-to-use proof of concept. For instance, CVE-2017-0037, a vulnerability that affects IE and Edge, is something attackers are likely to integrate soon.

ABOUT THE AUTHOR

Jérôme Segura

Principal Threat Researcher