June 24, 2026
·
02:32 AM
8 min read
When people think about a cyberattack, they usually imagine a hacker breaking into one computer, stealing files, and leaving. In reality, that’s often not how modern attacks work.
In many cases, the first computer a hacker compromises is just the starting point.
Once inside, attackers often try to move through the rest of the network, searching for more devices, more accounts, and more valuable data. This stage of an attack is called lateral movement, and it’s one of the most dangerous parts of a breach because it allows a small compromise to turn into a company-wide incident.
In this article, we’ll break down what lateral movement is, how hackers do it, and what your business can do to stop it.
Lateral movement is the process of a hacker moving from one system inside a network to another after gaining initial access.
For example, an attacker might first get into:
an employee laptop through a phishing email
a company VPN account using stolen credentials
a server with an unpatched vulnerability
a weakly secured remote desktop service
But once they get in, they don’t stop there. They often start looking for ways to access:
file servers
domain controllers
email systems
databases
admin accounts
backups
cloud-connected services
Think of it like someone breaking into a building through a side window, then walking room to room trying every unlocked door until they reach the office safe.
The first machine they compromise may not have much value by itself. Hackers move through a network because they’re usually after something bigger, such as:
sensitive customer data
financial records
saved passwords
administrator accounts
backup systems
intellectual property
control over critical systems
In ransomware attacks, lateral movement is especially important. Attackers often spend time spreading through the environment before deploying encryption so they can hit as many systems as possible at once.
Let’s say a small business employee clicks a malicious attachment in an email. Malware is installed on their computer, and the attacker now has a foothold inside the company.
From there, the attacker may:
Look around the infected computerThey search for saved passwords, VPN sessions, browser cookies, mapped drives, and documents that reveal how the network is set up.
Identify other systems on the networkThey look for file shares, servers, printers, remote management tools, or other computers that respond on the local network.
Steal or reuse credentialsIf the employee’s password is cached, weak, or reused elsewhere, the attacker may try it on other systems.
Access a more valuable machineThey might connect to a server, an IT admin workstation, or a machine with elevated privileges.
Escalate privilegesOnce they find an admin account or privileged system, they gain broader control.
Spread furtherThe attacker continues moving from system to system until they reach their target or have enough access to launch ransomware, steal data, or maintain persistence.
That entire process is lateral movement.
There are many ways attackers move through a network, but here are some of the most common.
One of the easiest ways to move laterally is by using legitimate usernames and passwords.
If an attacker compromises a device and finds:
saved passwords in browsers
reused employee passwords
cached credentials
admin passwords stored in scripts or notes
VPN or remote access credentials
they can try those credentials on other systems inside the network.
This is why attacks often don’t “look” like hacking at first. If the attacker is logging in with valid credentials, some activity may appear normal unless it’s being monitored closely.
Attackers frequently abuse legitimate tools that already exist in a Windows or business environment. This is sometimes called living off the land because they use tools administrators normally rely on.
Examples include:
Remote Desktop Protocol (RDP)
PowerShell
Windows Management Instrumentation (WMI)
PsExec
SMB network shares
remote management tools
If an attacker has the right credentials, they may not need to install anything noisy at all. They can simply use the same tools your IT team uses to manage systems.
Many businesses have shared folders and mapped drives so employees can access files easily. If permissions are too broad, a hacker on one machine may be able to browse shared folders, steal data, or find scripts and files that contain useful information.
Sometimes attackers find:
backup locations
spreadsheets with passwords
internal documentation
exported reports with customer information
software deployment shares
Even if a share doesn’t directly give them admin access, it can give them the information they need to move further.
In Windows environments, attackers may try to abuse authentication material stored in memory or cached on a system. Instead of knowing the actual password, they may use captured credential data to authenticate to other systems.
This is one reason why a compromise of a single admin workstation can be extremely dangerous. If privileged credentials are exposed on that machine, the attacker may be able to reuse them elsewhere without ever “guessing” the password.
Not every step of lateral movement uses stolen credentials. Sometimes the attacker finds another internal device with a known vulnerability and exploits it to gain access.
This could include:
old Windows systems
outdated server software
vulnerable NAS devices
unpatched remote management platforms
unsupported applications exposed internally
Businesses often focus on patching internet-facing systems, which is important, but internal systems matter too. Once an attacker is inside, the internal network becomes their playground.
A flat network is one where many devices can talk to each other freely with very few restrictions. In these environments, once an attacker gets in, moving around becomes much easier.
For example, if every workstation can reach every server, and every employee device can see shared resources across the business, a compromise can spread quickly.
Network segmentation helps reduce this risk by limiting which systems can communicate with one another.
Lateral movement isn’t always obvious, but there are warning signs that can point to it. Security tools and monitoring systems may detect things like:
a device suddenly scanning many other internal systems
one workstation attempting connections to multiple servers it normally never talks to
repeated authentication attempts across multiple devices
new remote desktop or PowerShell sessions between internal machines
access to administrative shares like C$ or ADMIN$
unusual login activity at odd hours
a normal user account suddenly accessing sensitive servers
tools like PsExec or WMI being used unexpectedly
large numbers of failed logins followed by a successful one
security software being disabled on multiple devices
One suspicious event by itself may not confirm an attack. But a pattern of unusual internal connections, credential use, and remote execution activity can be a strong sign that someone is moving through the environment.
Lateral movement is dangerous because it turns one compromised system into a much larger breach.
Without lateral movement, an attacker might only gain access to one employee computer. With lateral movement, they may be able to reach:
your file server
your accounting system
your backup server
your Microsoft 365-connected systems
your domain controller
your customer data
This is often the difference between a minor incident and a business-disrupting disaster.
The good news is that businesses can make lateral movement much harder. Here are some of the most effective ways to do that.
MFA makes stolen passwords much less useful. Even if an attacker gets a username and password, MFA can help stop them from using it to access other systems.
Not every employee needs administrative access. The fewer admin accounts that exist—and the fewer systems those accounts touch—the better.
IT staff should avoid using the same account for email, web browsing, and server administration. Privileged accounts should be separate and tightly controlled.
Anything inside the network can become a target once an attacker gets in. Keep servers, workstations, appliances, and internal applications updated.
Workstations should not always be able to talk freely to every server and every device. Segmenting systems by role helps contain a compromise.
Look for things like:
internal port scanning
sudden spikes in SMB or RDP activity
unusual PowerShell usage
repeated login attempts across multiple hosts
devices reaching systems they do not normally access
If RDP, SMB, WMI, or PowerShell remoting aren’t needed on certain systems, reduce or restrict them.
Use strong password policies, MFA, password managers, and secure credential storage. Avoid storing passwords in spreadsheets, notes, or scripts.
Good security visibility helps detect when one device starts acting like it’s trying to move through the network.
Have a plan for quickly isolating a device if it starts behaving suspiciously. Speed matters during a breach.
Hackers rarely stop at the first device they compromise. Once inside a business network, they often start looking for ways to move deeper, access more systems, and find the assets that matter most.
That’s what lateral movement is all about: turning a single foothold into broader control.
For small businesses, understanding this concept is important because it changes how you think about cybersecurity. Protection isn’t only about keeping attackers out—it’s also about stopping them from moving once they get in.
If your network has weak passwords, broad access permissions, unpatched systems, and little visibility into internal activity, one compromised device can quickly become a much bigger problem.
Cybersecurity isn’t just perimeter defense anymore. It’s visibility, containment, privilege control, and making sure one mistake doesn’t become a full-network incident.
If you want help assessing how exposed your business may be to lateral movement, Cyber Sight can help identify weaknesses in your environment and recommend practical ways to harden your network before an attacker finds them first.
Published on CyberSight News