Lateral movement is what attackers do after the first break-in: they move from one computer to another until they find the juicy stuff. That may be payroll data, admin accounts, source code, or cloud keys. This matters because the average data breach cost hit $4.88 million in 2024 [source: IBM].
TLDR: Lateral movement is the “sneak around the office” phase of a cyberattack. An attacker may start with one stolen password, then jump to 10 servers in under an hour if no one stops them. EDR watches devices, SIEM connects logs, and network detection tools watch traffic between systems. Use all three if you can, because each one sees a different part of the mess.
So, What Is Lateral Movement?
Think of your company network like a hotel.
An attacker gets into one room. Maybe through a stolen password. Maybe through a phishing email. Maybe through an old server that should have been patched months ago. Classic.
But one room is not enough. The attacker wants the safe. So they walk the halls. They try doors. They steal key cards. They peek into storage closets. In cybersecurity, that hallway walk is lateral movement.
Common tricks include:
- Using stolen passwords to log into other machines.
- Remote Desktop Protocol, also called RDP, to jump between computers.
- Pass the hash, where attackers reuse password data without knowing the real password.
- Admin tools like PowerShell, because normal tools look less suspicious.
- File shares to find documents, scripts, and secrets.
It is sneaky because it can look like normal work. Bob from accounting logs into a file server. Fine. Bob logs into 14 servers at 2:13 a.m. Not fine.
Why Lateral Movement Is So Annoying
The first infected device is only the start. The real damage often happens later.
Attackers move sideways to find better access. They want domain admin. That is the master key. Once they get it, they can create accounts, turn off defenses, steal data, or launch ransomware everywhere.
Honestly, it feels like chasing a raccoon in the ceiling. You hear noise in one spot. Then another. Then somehow it is in the kitchen.
That is why security teams use more than one tool. One camera is not enough.
EDR vs SIEM vs Network Detection Tools
These tools are often mixed up. They should not be. They answer different questions.
| Tool | What It Watches | Best At | Weak Spot |
|---|---|---|---|
| EDR | Laptops, desktops, servers | Seeing what happens on a device | Blind if no agent is installed |
| SIEM | Logs from many systems | Finding patterns across tools | Can drown you in noisy alerts |
| Network Detection | Traffic between systems | Spotting strange connections | May not see inside encrypted traffic |
EDR: The Guard on the Laptop
EDR means Endpoint Detection and Response. It watches endpoints. That means laptops, desktops, and servers.
EDR can spot a weird PowerShell command. It can see malware start. It can catch a suspicious login from a new process. It may even isolate the machine from the network.
This is great for lateral movement because many attacks start with one endpoint. EDR says, “Hey, this laptop just tried to dump passwords.” Very useful.
But there is a catch. If the attacker touches a device without EDR, you may miss it. Also, some servers are left out because someone feared “performance impact.” Then everyone acts shocked later.
SIEM: The Giant Log Brain
SIEM means Security Information and Event Management. It pulls logs from many places. Firewalls. Cloud apps. Servers. Identity tools. EDR alerts. Login records.
A SIEM is good at connecting dots.
For example:
- A user logs in from New York.
- Five minutes later, the same user logs in from Berlin.
- Then that user accesses an admin portal.
That should smell funny.
SIEM tools are powerful. But they can be noisy. Expect to waste time on weak rules if nobody tunes them. A bad SIEM setup can turn into a slot machine of alerts. Ding. Ding. Ding. Nothing useful.
Network Detection Tools: The Hallway Camera
Network detection tools watch traffic moving between systems. Many teams call this NDR, or Network Detection and Response.
These tools are great for spotting movement. They may see one workstation connecting to many servers. They may catch strange DNS requests. They may notice a device talking to a system it never touched before.
This helps when endpoints are missing agents. It also helps when attackers use real admin tools. The traffic still has to move.
The annoying part? Encrypted traffic can hide details. You may see that two systems talked, but not always what they said.
A Simple Use Case
A sales employee clicks a fake invoice. Malware runs on the laptop.
EDR sees PowerShell dumping credentials. It sends an alert.
The attacker uses one stolen password to connect to three file servers. Network detection sees the odd traffic pattern.
The same account then logs into the VPN from a strange country. SIEM connects the endpoint alert, server access, and VPN login.
Now the security team has a story. Not just random beeps.
Which Tool Should You Pick?
If you can only start with one, pick EDR. It gives strong detail on devices. Then add SIEM when you need wider log analysis. Add network detection when you want to catch movement between systems.
The best setup is simple:
- EDR tells you what happened on the machine.
- SIEM tells you how events connect.
- Network detection tells you where traffic went.
Lateral movement is the attacker’s hallway walk. Your job is to turn on the lights, lock the doors, and stop pretending Bob logs into 14 servers at 2 a.m. for fun.