The WannaCry ransomware incident has galvanized global media coverage and dominated discussion among information security professionals since Friday, May 12. The speed with which this malware was able to spread within enterprise networks and how rapidly so many large organizations were impacted is unsettling. Yet, as the dust begins to settle, it is clear that this episode has left a number of lessons in its wake–lessons to be harnessed by defenders and their adversaries.
While this attack is an expansive topic that will continue to evolve as more discoveries are made about the impact, origin, and spread of the WannaCry ransomware, it is also important to keep in mind that WannaCry is one of three major incidents to arise in the past month. Lessons provided by WannaCry are only deepened by the additional context of the fake Google Docs malicious cloud application incident of May 4, 2017 and the introduction of the Jaff encryption ransomware on May 11, 2017. First and most obvious, both Jaff and WannaCry show that the ransomware business model is far from obsolete. There is still a great deal of value to threat actors in holding data for ransom. Second, the novel attack vectors for WannaCry and the fake Google Docs cloud application show that innovation in leveraging new attack surfaces is happening among threat actors. The challenge for defenders is to internalize these revelations and develop an agile security posture that incorporates defense against existing risks and emergent attack vectors.
Figure 1 – WannaCry combined classic ransomware elements with powerful propagation potential
The explosive growth of ransomware in 2016 marked a dramatic shift in how many threat actors monetize phishing attacks. While certain ransomware tools were delivered using other mechanisms, tools like Locky and Cerber set the tone for the ransomware business model. These ransomware tools were delivered by massive numbers of phishing email to reach the largest number of victims. This business model has been once again put into action by the Jaff encryption ransomware following its debut just one week ago on May 11, 2017. However, the worm functionality demonstrated by WannaCry puts a unique spin on that model by reducing the infrastructure and resource expenditure necessary for the threat actor to maximize their ability to infect new hosts. The goal for both Jaff and WannaCry threat actors is still to reach as many victims as possible to maximize the number of potential ransom payments, lending credence to the notion that ransomware is far from obsolete as an avenue for online crime.
Figure 2 – Jaff relies on commonplace and familiar phishing narratives to infect victims
Figure 3 – Although a new ransomware, Jaff brings few new features to the table
While the propagation mechanisms of the fake “Google Docs” application that made headlines on May 4, 2017 and the WannaCry ransomware worm differ dramatically, both show that virulence is an important aspect of their overall strategy. Furthermore, each of these incidents shows a significant level of innovation by harnessing relatively new attack vectors. The fake “Google Docs” incident took advantage of users’ reliance on cloud services to propagate while WannaCry leveraged a vulnerability only recently disclosed and made public. However effective these attacks were in their own right, the long-term impact will be the future attacks inspired by these innovations. Whether the payload is a ransomware or some other category of malware, threat actors are watching and learning from these attacks. Furthermore, neither innovation is exclusive of the use phishing email as a means for making a “first contact” with a victim as was the case with the fake “Google Docs” application. By combining these promising innovations with a tried-and-trusted attack vector, threat actors will continue to gain access to enterprise data and hold it for ransom.
Figure 4 – Phishing email was used as a vector for attacking cloud infrastructure using a fake Google Docs web application
The high profile events of the past month have provided some indication that threat actors are quickening the pace of innovation and looking to combine these innovations with existing attack models. Both phishing and the ransomware tools delivered via phishing emails have proven very successful for threat actors and continued use of both can be expected. However, as threat actors learn from events like those from the past month it can be expected that they will attempt to implement their own versions using creative re-combinations of these techniques to launch attacks of their own.
To anticipate and mitigate these new attack vectors, those tasked with defending enterprises must adapt their security posture to changing paradigms. It is important to ensure there are agile defense and response processes that incorporate protections for multiple attack surfaces and at various stages of the attack life cycle. This effort begins with the basics of regular patching and network hygiene. It also requires the anticipatory education and empowerment of email users to engage with messages critically and act on suspicions, reporting potentially-malicious emails to the enterprise’s defenders. These internal reports can then be compared to external observations and intelligence reporting to identify the most immediate risks to an organization. The threat landscape is evolving, but in the face of robust, holistic, and human-centered defense strategies, attackers can be overcome.
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