Ransomware and Network Security

A ransomware attack unfolds like a heist. Attackers breach the perimeter, move quietly through your network, steal what they can, then encrypt everything at once—maximum impact, maximum pressure. The ransom note is just the reveal. By the time you see it, the real work is already done.

Network security's job is to break that chain before the finale.

The Anatomy of a Ransomware Attack

Ransomware isn't really about encryption. It's about how much damage an attacker can do before anyone notices they're inside.

Initial access gets them through the door. Phishing emails with malicious attachments remain the most common entry point. Exposed Remote Desktop Protocol (RDP) with weak passwords provides direct access—attackers use credential stuffing, brute force, or purchased credentials to walk right in. Unpatched VPNs and web applications offer exploitation opportunities. Some attackers simply buy access from specialists who compromise networks for resale.

Reconnaissance maps the territory. Attackers identify valuable data, locate backups (to destroy them later), and discover privileged accounts worth compromising. They establish multiple backdoors—if you find one entry point, they have others.

Lateral movement spreads the infection. Attackers compromise additional systems, steal credentials from each one, and escalate privileges until they reach domain administrators who control everything.

Data exfiltration happens before encryption. Attackers steal sensitive data to create leverage—even if you restore from backups, they threaten to publish what they took. This "double extortion" means victims face encrypted systems and data disclosure threats simultaneously.

Encryption is the final act. It deploys across many systems simultaneously, targeting production data and backups alike. The goal is to leave you with no options except paying.

How Ransomware Enters Networks

Email remains dominant. Phishing emails with malicious attachments or links to infected websites account for most initial compromises. Users clicking one wrong link can start the entire chain.

Remote Desktop Protocol exposed to the Internet is an open invitation. Attackers scan for exposed RDP constantly. Weak passwords fall to brute force; purchased credentials from previous breaches provide legitimate access.

Vulnerable services on Internet-facing systems get exploited. Unpatched VPN appliances, web applications, and other exposed services provide entry points that require no user interaction.

Supply chain compromises let attackers piggyback on trusted relationships. Compromising a software vendor or service provider provides access to all their customers.

Lateral movement inside networks uses stolen credentials, exploits internal vulnerabilities, or abuses legitimate tools like PowerShell and remote administration utilities. The same tools administrators use to manage networks, attackers use to spread through them.

Prevention: Keeping Attackers Out

Multiple layers prevent ransomware from gaining footholds.

Email security filters malicious attachments and links before users see them. Sandboxing detonates suspicious attachments in isolated environments to observe behavior. SPF, DKIM, and DMARC prevent email spoofing. Security awareness training helps users recognize phishing—the last line of defense when technical controls miss something.

Perimeter security blocks unnecessary inbound access. Firewalls restrict what can reach internal systems. VPN requires multi-factor authentication for remote access. Internet-facing services get patched promptly. The attack surface stays minimal—expose only what's essential.

Network segmentation limits how far attackers can spread. Separate network segments for workstations, servers, and critical systems mean ransomware on a workstation can't automatically reach servers. Communication between segments is restricted to necessary services only. Backup systems live on isolated networks attackers can't easily reach.

Access controls implement least privilege. Users and systems get only the access they need. Privileged access management protects administrative credentials. Unnecessary accounts and services get disabled. Multi-factor authentication protects everything, especially administrative access.

Vulnerability management closes the gaps attackers exploit. Systems get patched promptly. Regular scans identify vulnerabilities before attackers do. Internet-facing and critical systems get priority. Misconfigurations that create vulnerabilities get fixed.

Detection: Catching Attackers Early

Network monitoring can detect ransomware activity before encryption completes—or even before it begins.

Unusual traffic patterns signal infections. Workstations communicating with unusual external IP addresses indicate command-and-control traffic. Internal port scanning reveals reconnaissance. Unusual SMB traffic patterns suggest lateral movement. Large data transfers to external destinations expose exfiltration in progress.

Behavioral analysis identifies anomalies. Sudden spikes in file modifications mean encryption is happening. Unusual login patterns—off-hours, unusual locations—indicate compromised credentials. Execution of suspicious binaries or scripts catches malware deployment.

Intrusion detection systems identify known attack patterns: exploit attempts against vulnerable services, malware command-and-control communication, and recognized ransomware behaviors.

SIEM correlation combines logs from multiple sources to reveal multi-stage attacks. Individual suspicious activities might seem innocuous. Correlated patterns expose attacks in progress.

Early detection enables response before complete encryption. Catching an attack during lateral movement rather than during encryption changes the outcome entirely.

Containment: Stopping the Spread

When ransomware is detected, speed matters.

Network isolation immediately disconnects infected systems from networks, preventing spread. Network zones get segmented to contain infections within smaller perimeters. Internet access gets cut to prevent command-and-control communication and data exfiltration.

Credential rotation changes passwords for potentially compromised accounts, especially administrative ones. Compromised user accounts get disabled. Cached credentials get reset.

Backup protection verifies that backups are offline or immutable and can't be encrypted. Some ransomware specifically hunts backup systems—ensuring backup isolation is critical.

Endpoint isolation tools can automatically quarantine systems showing ransomware indicators without manual network disconnection.

Backups: The Ultimate Defense

With good backups, you don't need to pay ransom.

The 3-2-1 backup rule: three copies of data, on two different media types, with one copy offsite. Immutable backups can't be modified or deleted for a retention period, protecting against ransomware that targets backups. Offline backups disconnected from networks can't be encrypted by attackers.

Regular testing ensures backups actually restore. Backup monitoring verifies completion. Retention policies maintain sufficient history to restore from before infections occurred.

Ransomware attacks specifically hunt for and destroy backups before encrypting production systems. Network-isolated or cloud-based immutable backups defeat this strategy.

The Ransomware Business

The ransomware ecosystem has professionalized. Ransomware-as-a-Service (RaaS) models let developers create ransomware and provide it to affiliates who conduct attacks, splitting payments.

This lowers barriers to entry—attackers don't need malware development skills. RaaS operations provide support, payment infrastructure, and professional negotiation services. Major groups like Conti, REvil, and LockBit operate like businesses, complete with customer service for their victims.

This professionalization makes ransomware more sophisticated and widespread.

Multi-Layered Extortion

Modern ransomware attacks rarely stop at encryption.

Double extortion combines encryption with data theft. Even if you restore from backups, attackers threaten to publish stolen data unless paid.

Triple extortion adds pressure on the victim's customers or partners, or threatens DDoS attacks if ransom isn't paid.

These approaches increase success rates for attackers by eliminating the "just restore from backup" escape route.

The Payment Question

Security professionals and law enforcement recommend not paying ransoms.

Payment funds criminal operations, encouraging more attacks. Payment doesn't guarantee decryption—some ransomware can't decrypt even with keys. Payment marks organizations as willing to pay, increasing future targeting.

But organizations face difficult decisions when critical systems are encrypted and backups don't exist. Some pay despite recommendations.

The better approach is preventing situations where payment seems necessary: good backups, defense in depth, and incident response planning before you need it.