Ransomware is a form of malware that encrypts a victim’s files and demands payment in order to restore access. Ransomware attacks have been rapidly increasing in recent years, affecting individuals, businesses, hospitals, and critical infrastructure. Understanding how ransomware spreads is crucial to defending against these threats. There are several common infection vectors that enable ransomware to penetrate systems and networks.
Email Attachments
One of the most prevalent ways ransomware spreads is through malicious email attachments. Cybercriminals send emails with infected file attachments, often masquerading as legitimate documents like invoices, resumes, or shipping notices. When unsuspecting users open these attachments, the ransomware is able to execute and encrypt their systems.
Some types of dangerous email attachments that distribute ransomware include:
- Microsoft Office files like Word documents or Excel spreadsheets with malicious macros
- Executables files like those ending in .exe
- JavaScript or PDF files exploiting vulnerabilities
- Infected image files
Users need to be cautious about opening attachments from unknown or suspicious senders. Anti-spam filters are not always able to detect and block these emails. Sensitizing employees through cybersecurity awareness training can help mitigate the risk of opening infected attachments.
Malicious Links
Ransomware is also commonly delivered through malicious links in phishing emails or on compromised websites. These links may advertise deals, claim a user needs to update software, prompt a user to open a document, or have other deceiving messages aimed at tricking the victim into clicking.
When users click these links, a drive-by download occurs in the background to install the ransomware payload on their device without any action on their part beyond visiting the site. Drive-by ransomware attacks are simple yet effective at infecting many victims quickly.
Some examples of phishing links that lead to ransomware include:
- Fake notification emails claiming a shipment requires payment or action
- Social media messages containing shortened URLs from untrusted sources
- Forged login pages requesting credentials
- Links claiming users must install a software update urgently
Being vigilant against unknown links and verifying legitimacy before clicking is the best defense. Hovering over links to inspect their actual destination is one way to identify malicious links. Organizations should also filter web traffic to block access to known malicious sites.
Network Propagation
Once ransomware infiltrates a system or network, it can then traverse and infect other machines and servers if not contained. Ransomware like WannaCry and NotPetya contained worm-like features enabling this lateral movement across networks.
One method of network propagation is by brute forcing login credentials to access other systems where the same passwords have been used. Ransomware may also utilize valid accounts with excessive user privileges to move across a network.
This network propagation occurs quickly and can render entire networks inaccessible. Segmenting sections of the network and requiring strong, unique passwords for each system are some measures that can limit these attacks.
Software Vulnerabilities
Hackers often exploit vulnerabilities in software programs and operating systems to deliver ransomware. When discovered, these security holes enable them to remotely compromise systems with no action required by victims.
Common exploited vulnerabilities that pave the way for ransomware attacks include:
- Unpatched or outdated applications like Flash or Java
- Default, weak, or stolen remote desktop credentials
- Unpatched operating systems like Windows machines not updated to the latest version
- Vulnerabilities like EternalBlue used by WannaCry
Regular patching, strong remote access credentials, and updating to the latest software versions are key for closing security gaps targeted by ransomware threat actors.
Infected Websites
Websites compromised by hackers are a common vector for ransomware and other malware. These infected sites contain code that PROFILEs visitors’ computers and silently installs ransomware in the background through drive-by downloads or other techniques.
High-traffic websites that fail to secure servers and keep software updated provide prime targets. Unfortunately users can get hit just by briefly visiting such sites while browsing.
Website owners need to monitor for indicators of compromise and check that they run the latest software versions without vulnerabilities. Users should avoid browsing to suspicious, hacked sites and steer clear of downloads or popups on unrecognized sites. An ad blocker can also help prevent some infected site drive-by attacks.
Fake Software
Masquerading corrupted software as legitimate programs is another ransomware trick. This includes torrented or cracked software infected with ransomware payloads by hackers.
Downloading fake anti-virus software, media apps, document creators, games, or other cracked programs from questionable sources carries a high ransomware risk.
Sticking to official sources like app stores, reliable download sites, and the vendor’s homepage helps avoid trojanized fake software. Since torrents in particular are known attack vectors, many enterprises block their use entirely.
Infected Storage
USB drives, external hard drives, CDs, and DVDs can also harbor ransomware. When users plug infected storage into a computer, the ransomware automatically executes to infect the host system.
This may occur through autorun features on the media or other techniques that run the code on connection. In high-security environments like industrial control facilities, even basics like USB drives should not be permitted without approval to reduce infection risks.
Risky Locations
There are certain locations known for actively spreading ransomware and other threats, whether intentionally or not. Accessing the internet through these risky hotspots makes users more prone to attacks through various vectors.
Some examples of locations correlated with a higher ransomware infection risk include:
- Public WiFi like airports, hotels, cafes
- Internet cafes with shared PCs
- Conference and trade show networks
- Airline in-flight WiFi
Avoiding sensitive browsing on public networks, using a VPN, taking extra caution with downloads, and ensuring devices are up-to-date are some precautions when accessing the internet from these types of places.
Mitigation Strategies
There are a number of strategies both individuals and organizations can employ to reduce the risk of ransomware infections:
- Implement cybersecurity awareness training to educate employees on ransomware risks and response
- Keep all software patched and up-to-date to eliminate vulnerabilities
- Install effective endpoint protection with anti-ransomware capabilities
- Utilize email security and web filtering to block malicious sites and attachments
- Require strong passwords and enable multi-factor authentication
- Back up data regularly and keep backups offline and protected
- Segment networks to prevent lateral movement
Combining user education, technology safeguards, and solid backup practices provides defense in depth against ransomware outbreaks. However, awareness of the common infection methods is also key to preventing and containing attacks.
Impact of Ransomware Attacks
The impact of even a single ransomware infection can be severe, resulting in:
- Loss of access to critical data and applications
- Revenue losses from downtime and business disruption
- Costly recovery and remediation efforts
- Reputational harm and loss of customer trust
For businesses in particular, the consequences are often grave. One study found the average cost of ransomware attacks for businesses is over $760,000.
Government agencies, hospitals, and critical infrastructure carry even greater risk, where ransomware incidents can endanger lives and safety when critical systems go down. Even if recovered through backups, the downtime can lead to dangerous delays in time-sensitive operations.
With the potential stakes so high, focusing on ransomware prevention is paramount.
Recent Ransomware Trends
Some emerging trends provide insight into how ransomware tactics and malware continue to evolve:
- Ransomware-as-a-Service model lowers barrier for cybercriminals to launch attacks
- Triple extortion adds additional pressure on victims by threatening to publish data
- Shifting from mass campaigns to more targeted, manual attacks
- Leveraging anonymizing services like Tor to avoid detection
- Expanding targets to cloud environments and Linux systems
Staying on top of the latest developments through threat intelligence enables more agile defense against ransomware. Organizations must think beyond just prevention and also plan how to quickly contain and remediate inevitable incidents.
Conclusion
Ransomware remains a severe cyber threat for individuals and organizations globally. While email was once the most prolific attack vector, ransomware campaigns increasingly rely on a diverse array of infection methods. Blocking malicious attachments and links provide a good first line of defense. However, shoring up vulnerabilities, avoiding high-risk software and sites, segmenting networks, updating backups, and training employees are essential for a mature security posture against ransomware in 2023 and beyond.
