Ransomware is a remote, digital shakedown. It is disruptive and
expensive, and it affects all kinds of organizations, from cutting
edge
technology firms, to the
industry, to
environments. Infections have forced hospitals to
away patients and law enforcement to
cases against drug dealers. Ransomware operators have recently
begun combining encryption with the threat of
leak and exposure in order to increase leverage against victims.
There may be a silver lining, however; Mandiant Intelligence research
suggests that focusing defensive efforts in key areas and acting
quickly may allow organizations to stop ransomware before it is deployed.
Mandiant Intelligence examined dozens of ransomware incident
response investigations from 2017 to 2019. Through this research, we
identified a number of common characteristics in initial intrusion
vectors, dwell time, and time of day of ransomware deployment. We also
noted threat actor innovations in tactics to maximize profits (Figure
1). Incidents affected organizations across North America, Europe,
Asia Pacific, and the Middle East in nearly every sector category,
including financial services, chemicals and materials, legal and
professional services, local government, and healthcare. We observed
intrusions attributed to financially motivated groups such as
TEMP.MixMaster, and dozens of additional activity sets.
Figure 1: Themes Observed in Ransomware Incidents
These incidents provide us with enhanced insight into ransomware
trends that can be useful for network defenders, but it is worth
bearing in mind that this data represents only a sample of all
activity. For example, Mandiant ransomware investigations increased
860% from 2017 to 2019. The majority of these incidents appeared to be
post-compromise infections, and we believe that threat actors are
accelerating use of tactics including post compromise deployment to
increase the likelihood of ransom payment. We also observed incidents
in which ransomware was executed immediately, for example GANDCRAB and
GLOBEIMPOSTER incidents, but most of the intrusions examined were
longer duration and more complex post-compromise deployments.
We noted several initial infection vectors across multiple
ransomware incidents, including RDP, phishing with a malicious link or
attachment, and drive by download of malware facilitating follow-on
activity. RDP was more frequently observed in 2017 and declined in
2018 and 2019. These vectors demonstrate that ransomware can enter
victim environments by a variety of means, not all of which require
user interaction.
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The number of days elapsed between the first evidence of malicious
activity and the deployment of ransomware ranged from zero to 299 days
(Figure 2). That is, dwell times range quite widely, and in most
cases, there was a time gap between first access and ransomware
deployment. For 75 percent of incidents, at least three days passed
between the first evidence of malicious activity and ransomware deployment.
This pattern suggests that for many organizations, if initial
infections are detected, contained, and remediated quickly, the
significant damage and cost associated with a ransomware infection
could be avoided. In fact, in a handful of cases, Mandiant
incident responders and FireEye Managed Defense contained and
remediated malicious activity, likely preventing ransomware
deployment. Several investigations discovered evidence of ransomware
installed into victim environments but not yet successfully executed.
Figure 2: Days elapsed between initial
access and ransomware deployment
In 76% of incidents we reviewed, ransomware was executed in victim
environments after hours, that is, on a weekend or before 8:00 a.m. or
after 6:00 p.m. on a weekday, using the time zone and customary work
week of the victim organization (Figure 3 and Figure 4). This
observation underscores that threat actors continue working even when
most employees may not be.
Some attackers possibly intentionally deploy ransomware after hours,
on weekends, or during holidays, to maximize the potential
effectiveness of the operation on the assumption that any remediation
efforts will be implemented more slowly than they would be during
normal work hours. In other cases, attackers linked ransomware
deployment to user actions. For example, in 2019 incidents at retail
and professional services firms, attackers created an Active Directory
Group Policy Object to trigger ransomware execution based on user log
on and log off.
Figure 3: Ransomware execution frequently
takes place after hours
Figure 4: Ransomware execution by hour of
the day
Organizations seeking to prevent or mitigate the effects of
ransomware infections could consider the following steps. For more
comprehensive recommendations for addressing ransomware, please refer
to our blog post:
Protection and Containment Strategies: Practical Guidance for
Endpoint Protection, Hardening, and Containment and the
linked
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Ransomware is disruptive and costly. Threat actor innovations have
only increased the potential damage of ransomware infections in recent
years, and this trend shows no sign of slowing down. We expect that
financially motivated actors will continue to evolve their tactics to
maximize profit generated from ransomware infections. We anticipate
that post-compromise ransomware infections will continue to rise and
that attackers will increasingly couple ransomware deployment with
other tactics, such as data theft and extortion, increasing ransom
demands, and targeting critical systems.
The good news is that particularly with post-compromise infections,
there is often a window of time between the first malicious action and
ransomware deployment. If network defenders can detect and remediate
the initial compromise quickly, it is possible to avoid the
significant damage and cost of a ransomware infection.
Register for our upcoming
webinar to learn more.