User containment is a unique and innovative defense mechanism that stops human-operated attacks in their tracks. We’ve added user containment to the automatic attack disruption capability in Microsoft Defender for Endpoint. User containment is automatically triggered by high-fidelity signals and limits attackers’ ability to move laterally within a network regardless of the compromised account’s Active Directory state or privilege level.
The increased connectivity of computers and the growth of Bring Your Own Device (BYOD) in most organizations is making the distribution of malicious software (malware) easier. Unlike other types of malicious programs that may usually go undetected for a longer period, a ransomware attack is usually experienced immediately, and its impact on information technology infrastructure is often irreversible.
As part of Microsoft’s Detection and Response Team (DART) Incident Response engagements, we regularly get asked by customers about “paying the ransom” following a ransomware attack. Unfortunately, this situation often leaves most customers with limited options, depending on the business continuity and disaster recovery plans they have in place.
The two most common options are either to pay the ransom (with the hopes that the decryption key obtained from the malicious actors works as advertised) or switch gears to a disaster recovery mode, restoring systems to a known good state.
The unfortunate truth about most organizations is that they are often only left with the only option of paying the ransom, as the option to rebuild is taken off the table by lack of known good backups or because the ransomware also encrypted the known good backups. Moreover, a growing list of municipalities around the U.S. has seen their critical infrastructure, as well as their backups, targeted by ransomware, a move by threat actors to better guarantee a payday.
We never encourage a ransomware victim to pay any form of ransom demand. Paying a ransom is often expensive, dangerous, and only refuels the attackers’ capacity to continue their operations; bottom line, this equates to a proverbial pat on the back for the attackers. The most important thing to note is that paying cybercriminals to get a ransomware decryption key provides no guarantee that your encrypted data will be restored.
So, what options do we recommend? The fact remains that every organization should treat a cybersecurity incident as a matter of when it will happen and not whether it will happen. Having this mindset helps an organization react quickly and effectively to such incidents when they happen. Two major industry standard frameworks, the Sysadmin, Audit, Network, and Security (SANS) and the National Institute of Standards and Technology (NIST), both have published similar concepts on responding to malware and cybersecurity incidents. The bottom line is that every organization needs to be able to plan, prepare, respond, and recover when faced with a ransomware attack.
Outlined below are steps designed to help organizations better plan and prepare to respond to ransomware and major cyber incidents.
How to plan and prepare to respond to ransomware
1. Use an effective email filtering solution
According to the Microsoft Security Intelligence Report Volume 24 of 2018, spam and phishing emails are still the most common delivery method for ransomware infections. To effectively stop ransomware at its entry point, every organization needs to adopt an email security service that ensures all email content and headers entering and leaving the organization are scanned for spam, viruses, and other advanced malware threats. By adopting an enterprise-grade email protection solution, most cybersecurity threats against an organization will be blocked at ingress and egress.
2. Regular hardware and software systems patching and effective vulnerability management
Many organizations are still failing to adopt one of the age-old cybersecurity recommendations and important defenses against cybersecurity attacks—applying security updates and patches as soon as the software vendors release them. A prominent example of this failure was the WannaCry ransomware events in 2017, one of the largest global cybersecurity attacks in the history of the internet, which used a leaked vulnerability in Windows networking Server Message Block (SMB) protocol, for which Microsoft had released a patch nearly two months before the first publicized incident. Regular patching and an effective vulnerability management program are important measures to defend against ransomware and other forms of malware and are steps in the right direction to ensure every organization does not become a victim of ransomware.
3. Use up-to-date antivirus and an endpoint detection and response (EDR) solution
While owning an antivirus solution alone does not ensure adequate protection against viruses and other advanced computer threats, it’s very important to ensure antivirus solutions are kept up to date with their software vendors. Attackers invest heavily in the creation of new viruses and exploits, while vendors are left playing catch-up by releasing daily updates to their antivirus database engines. Complementary to owning and updating an antivirus solution is the use of EDR solutions that collect and store large volumes of data from endpoints and provide real-time host-based, file-level monitoring and visibility to systems. The data sets and alerts generated by this solution can help to stop advanced threats and are often leveraged for responding to security incidents.
4. Separate administrative and privileged credentials from standard credentials
Working as a cybersecurity consultant, one of the first recommendations I usually provide to customers is to separate their system administrative accounts from their standard user accounts and to ensure those administrative accounts are not useable across multiple systems. Separating these privileged accounts not only enforces proper access control but also ensures that a compromise of a single account doesn’t lead to the compromise of the entire IT infrastructure. Additionally, using Multi-Factor Authentication (MFA), Privileged Identity Management (PIM), and Privileged Access Management (PAM) solutions are ways to effectively combat privileged account abuse and a strategic way of reducing the credential attack surface.
5. Implement an effective application allow lists
It’s very important as part of a ransomware prevention strategy to restrict the applications that can run within an IT infrastructure. Application allow lists ensures only applications that have been tested and approved by an organization can run on the systems within the infrastructure. While this can be tedious and presents several IT administrative challenges, this strategy has been proven effective.
6. Regularly back up critical systems and files
The ability to recover to a known good state is the most critical strategy of any information security incident plan, especially ransomware. Therefore, to ensure the success of this process, an organization must validate that all its critical systems, applications, and files are regularly backed up and that those backups are regularly tested to ensure they are recoverable. Ransomware is known to encrypt or destroy any file it comes across, and it can often make them unrecoverable; consequently, it’s of utmost importance that all impacted files can be easily recovered from a good backup stored at a secondary location not impacted by the ransomware attack.
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