Adding Ransomware to Security Radars

1 year ago
Eric Vanderburg

Ransomware is the quickest way to turn your valuable data into garbage.  Ransomware is a form of malicious software that blocks access to user data such as documents, spreadsheets, pictures, music, or videos, typically by encrypting those files.  At this point, the ransomware will display a demand for payment in order to send the victim the decryption keys to the data.

Businesses and consumers often do not know what they have until it is encrypted.  It is then that they realize their Christmas list, family photos, and personal financials are inaccessible.  It can be much worse for companies.  Imagine the impact when payroll data, product formulas, or inventory records are suddenly unavailable.  Now imagine a doctor who is unable to prescribe medicine or perform an operation because the prescription information or patient records they need are encrypted.  As you can see, the impact of ransomware can be severe.

Despite ransomware’s severe impact, its attack vectors are more mundane.  Ransomware is obtained through a variety of well-known routes including email, websites, online advertising, exploits on system vulnerabilities, and infected files on shared folders or cloud file sharing services.

Email

Emails, particularly phishing emails, frequently entice users to open attachments that contain ransomware or to click links leading to infected websites.  The techniques used here are the same ones used by scammers, hackers, and other malware distributors.  Protection techniques include screening attachments with antivirus tools and utilizing email gateway scanning and filtering tools.  It is also important to educate employees or family members on how to recognize suspicious emails.

Infected websites and online advertising

Ransomware is also distributed from infected websites and through online ads.  Extortionists seed websites with malicious code and then wait for unsuspecting Internet users to visit a compromised site and get infected with their ransomware.  The likelihood of infection from such sites can be greatly reduced by utilizing a web filter, scanning websites for malware or by browsing the web in a virtual machine.

Extortionists also create ads on social media or in search engines that download the malware.  Ads might pretend to be a flash player update, help or chat ads, or fake antivirus.  These ads are collectively known as malvertising.  The best way to protect against ransomware distributed through malvertising is by using an ad blocker.  There are many extensions for common browsers or standalone applications that can perform this activity.

Shared folders or cloud file sharing

Ransomware can also be obtained when a computer is connected to a network share that has ransomware on it.  Many ransomware variants are capable of spreading to shares that a computer is connected through, typically through mapped drives.  Ransomware can also infect your machine if you are using a cloud file sharing service that synchronizes files between machines.  If a personal computer is infected and has the cloud file sharing software on it, it can replicate the malware to other computers that are part of the sharing relationship, infecting them all in the process.  Monitor file servers for mass file changes to detect ransomware behavior and scan files that are placed on network shares.  Similarly, equip each computer that utilizes cloud file sharing applications with antivirus software and segment business cloud file stores from personal ones.

System vulnerabilities

Vulnerabilities in operating systems, applications and browser plugins are well documented once they have been discovered.  Attackers create exploit kits to target these vulnerabilities and then other malicious actors utilize these exploit kits to deliver malware to your machine.  The most common exploits are those related to operating systems such as Windows, applications such as Adobe Acrobat, or browser plugins such as Java, Flash, or Silverlight.  The best way to protect against the exploitation of such vulnerabilities is to keep systems, applications, and plugins updated to the latest version.  Vendors frequently release new versions or patches to software that fix the vulnerabilities that have been discovered.  Applying these updates can prevent those vulnerabilities from being exploited.

Exceptions

There will always be exceptions in a security system.  No system will protect you one hundred percent of the time and that is why it is important to have contingency plans.  When ransomware gets past your defenses, and it will at some point, be sure you have up-to-date backups of critical files so that you can remove the malware and encrypted files and then restore clean versions of the files back to computers.  Backup solutions should be distinct from production systems.  For example, a hard drive connected to a computer or a network attached storage device are both accessible from an infected machine so they are likely to be infected too.  However, tape backups or online backup services are distinct from production storage and can be relied upon to restore clean copies of data if the restore points predate the infection date.

As always, thoughts and ideas are my own. This insight wouldn’t be possible without the help of my associates at Bitdefender