How to Better Protect Your Network from Ransomware

Ransomware is the fastest growing malware threat, targeting users of all types, from the home user to the corporate network.

On average, more than 4,000 ransomware attacks have occurred daily since January 1, 2016. This is a 300-percent increase over the approximately 1,000 attacks per day seen in 2015. There are very effective prevention and response actions that can significantly mitigate the risk posed to your organization.

Ransomware targets home users, businesses, and government networks and can lead to temporary or permanent loss of sensitive or proprietary information, disruption to regular operations, financial losses incurred to restore systems and files, and potential harm to an organization’s reputation.

Ransomware may direct a user to click on a link to pay a ransom; however, the link may be malicious and could lead to additional malware infections. Some ransomware variants display intimidating messages, such as: “Your computer was used to visit websites with illegal content. To unlock your computer, you must pay a $300 fine.” “You only have 72 hours to submit the payment. If you do not send money within provided time, all your files will be permanently encrypted and no one will be able to recover them.”

What is Ransomware? • • • Ransomware is a form of malware that targets your critical data and systems for the purpose of extortion. Ransomware is frequently delivered through spearphishing emails. After the user has been locked out of the data or system, the cyber actor demands a ransom payment. After receiving payment, the cyber actor will purportedly provide an avenue to the victim to regain access to the system or data. Recent iterations target enterprise end users, making awareness and training a critical preventive measure.

Protecting Your Networks from Ransomware

Educate Your Personnel About Ransomware

Attackers often enter the organization by tricking a user to disclose a password or click on avirus-laden email attachment. Remind employees to never click unsolicited links or open unsolicited attachments in emails.

To improve workforce awareness, the internal security team may test the training of an organization’s workforce with simulated phishing emails.

Proactive Prevention is the Best Defense Against Ransomware

Prevention is the most effective defense against ransomware and it is critical to take precautions for protection. Infections can be devastating to an individual or organization, and recovery may be a difficult process requiring the services of a reputable data recovery specialist. The U.S. Government (USG) recommends that users and administrators take the following preventive measures to protect their computer networks from falling victim to a ransomware infection:

Ransomware Preventive Measures

• Implement an awareness and training program. Because end users are targets, employees and individuals should be aware of the threat of ransomware and how it is delivered.
• Enable strong spam filters to prevent phishing emails from reaching the end users and authenticate inbound email using technologies like Sender Policy Framework (SPF), Domain Message Authentication Reporting and Conformance (DMARC), and DomainKeys Identified Mail (DKIM) to prevent email spoofing.
• Scan all incoming and outgoing emails to detect threats and filter executable files from reaching end users.
• Configure firewalls to block access to known malicious IP addresses.
• Patch operating systems, software, and firmware on devices. Consider using a centralized patch management system.
• Set anti-virus and anti-malware programs to conduct regular scans automatically.
• Manage the use of privileged accounts based on the principle of least privilege: no users should be assigned administrative access unless absolutely needed; and those with a need for administrator accounts should only use them when necessary
• Configure access controls—including file, directory, and network share permissions— with least privilege in mind. If a user only needs to read specific files, the user should not have write access to those files, directories, or shares.
• Disable macro scripts from office files transmitted via email. Consider using Office Viewer software to open Microsoft Office files transmitted via email instead of full office suite applications.
• Implement Software Restriction Policies (SRP) or other controls to prevent programs from executing from common ransomware locations, such as temporary folders supporting popular Internet browsers or compression/decompression programs, including the AppData/LocalAppData folder.
• Consider disabling Remote Desktop protocol (RDP), if it is not being used.
• Use application whitelisting, which only allows systems to execute programs known and permitted by security policy.
• Execute operating system environments or specific programs in a virtualized environment.
• Categorize data based on organizational value and implement physical and logical separation of networks and data for different organizational units.

Business Continuity Considerations

• Back up data regularly. Verify the integrity of those backups and test the restoration process to ensure it is working.
• Conduct an annual penetration test and vulnerability assessment.
• Secure your backups. Ensure backups are not connected permanently to the computers and networks they are backing up. Examples are securing backups in the cloud or physically storing backups offline. Some instances of ransomware have the capability to lock cloud-based backups when systems continuously back up in real time, also known as persistent synchronization. Backups are critical in ransomware recovery and response; if you are infected, a backup may be the best way to recover your critical data.