undermybelt Detecting Lateral Movement in Network
When to Use
- Monitoring enterprise networks for post-compromise lateral movement patterns (pass-the-hash, RDP hopping, PSExec)
- Building SIEM detection rules and alerts for common MITRE ATT&CK lateral movement techniques (T1021, T1570)
- Investigating suspected breaches by analyzing authentication patterns and network connections between internal hosts
- Hunting for anomalous east-west traffic patterns that indicate an attacker pivoting through the network
- Validating that network segmentation and access controls effectively limit lateral movement paths
Do not use as a substitute for endpoint detection and response (EDR) tools, for monitoring only north-south traffic while ignoring internal traffic flows, or without baseline knowledge of normal internal communication patterns.
Prerequisites
- Network security monitoring deployed at internal choke points (Zeek, Suricata, or network TAPs)
- SIEM platform (Splunk, Elastic, Microsoft Sentinel) collecting Windows Security Event Logs, DNS, and flow data
- Windows Event Log forwarding configured for Security events (4624, 4625, 4648, 4672, 4768, 4769)
- Baseline of normal internal authentication and connection patterns
- Understanding of MITRE ATT&CK Lateral Movement tactics (TA0008)
Workflow
Step 1: Configure Log Collection for Lateral Movement Detection
# Windows Event Logs to collect (via WEF or agent):
# Security Log:
# 4624 - Successful logon (Type 3=Network, Type 10=RemoteInteractive)
# 4625 - Failed logon
# 4648 - Logon using explicit credentials (RunAs, PsExec)
# 4672 - Special privileges assigned (admin logon)
# 4768 - Kerberos TGT request
# 4769 - Kerberos service ticket request
# 4776 - NTLM authentication (credential validation)
# System Log:
# 7045 - New service installed (PsExec indicator)
# 7036 - Service started/stopped
# Configure Windows Event Forwarding (WEF) subscription
# On the collector server (PowerShell):
# wecutil cs lateral-movement-subscription.xml
# Filebeat configuration for Windows Event Log shipping
cat > /etc/filebeat/modules.d/security.yml << 'EOF'
- module: system
auth:
enabled: true
var.paths: ["/var/log/auth.log"]
syslog:
enabled: true
- module: zeek
connection:
enabled: true
var.paths: ["/opt/zeek/logs/current/conn.log"]
dns:
enabled: true
var.paths: ["/opt/zeek/logs/current/dns.log"]
smb_mapping:
enabled: true
var.paths: ["/opt/zeek/logs/current/smb_mapping.log"]
dce_rpc:
enabled: true
var.paths: ["/opt/zeek/logs/current/dce_rpc.log"]
EOF
# Zeek configuration for lateral movement detection
# Enable SMB, DCE-RPC, and Kerberos logging
cat >> /opt/zeek/share/zeek/site/local.zeek << 'EOF'
@load policy/protocols/smb
@load policy/protocols/conn/known-hosts
@load policy/protocols/conn/known-services
@load frameworks/intel/seen
EOF
sudo zeekctl deploy
Step 2: Build Detection Rules for Common Lateral Movement Techniques
# Splunk SPL queries for lateral movement detection
# 1. Detect PsExec usage (new service creation on remote hosts)
# index=wineventlog EventCode=7045 ServiceName="PSEXESVC" OR ServiceName="*psexec*"
# | stats count by ComputerName, ServiceName, ImagePath
# | where count > 0
# 2. Detect Pass-the-Hash (Type 3 logon with NTLM)
# index=wineventlog EventCode=4624 LogonType=3 AuthenticationPackageName="NTLM"
# | where TargetUserName!="ANONYMOUS LOGON" AND TargetUserName!="$"
# | stats count dc(ComputerName) as unique_hosts by TargetUserName, IpAddress
# | where unique_hosts > 3
# 3. Detect RDP lateral movement (Type 10 logon from internal IPs)
# index=wineventlog EventCode=4624 LogonType=10
# | where cidrmatch("10.0.0.0/8", IpAddress) OR cidrmatch("192.168.0.0/16", IpAddress)
# | stats count dc(ComputerName) as rdp_hosts by TargetUserName, IpAddress
# | where rdp_hosts > 2
# Elastic SIEM detection rules (KQL)
# event.code: "4624" and winlog.event_data.LogonType: "3"
# and winlog.event_data.AuthenticationPackageName: "NTLM"
# and not winlog.event_data.TargetUserName: *$
# and source.ip: (10.0.0.0/8 or 172.16.0.0/12 or 192.168.0.0/16)
# Sigma rules for lateral movement detection
# Install sigma and convert to target SIEM format
pip3 install sigma-cli
cat > lateral_movement_pth.yml << 'EOF'
title: Pass-the-Hash Lateral Movement Detection
id: f8d98d6c-7a07-4d74-b064-dd4a3c244528
status: experimental
description: Detects network logon with NTLM authentication to multiple hosts
logsource:
product: windows
service: security
detection:
selection:
EventID: 4624
LogonType: 3
AuthenticationPackageName: NTLM
filter:
TargetUserName|endswith: '$'
condition: selection and not filter
timeframe: 15m
count:
field: ComputerName
min: 3
group-by: TargetUserName
level: high
tags:
- attack.lateral_movement
- attack.t1550.002
EOF
# Convert Sigma rule to Splunk SPL
sigma convert -t splunk lateral_movement_pth.yml
# Convert to Elastic query
sigma convert -t elasticsearch lateral_movement_pth.yml
Step 3: Network-Level Detection with Zeek
# Detect SMB lateral movement (admin$ and c$ share access)
cat /opt/zeek/logs/current/smb_mapping.log | \
zeek-cut ts id.orig_h id.resp_h path | \
grep -iE "(admin\$|c\$|ipc\$)" | \
sort -t$'\t' -k2 | uniq -c | sort -rn
# Detect hosts connecting to many internal hosts on port 445 (SMB spreading)
cat /opt/zeek/logs/current/conn.log | \
zeek-cut ts id.orig_h id.resp_h id.resp_p | \
awk '$4 == 445' | \
awk '{print $2}' | sort | uniq -c | sort -rn | head -10
# Detect WMI lateral movement (DCE-RPC to IWbemServices)
cat /opt/zeek/logs/current/dce_rpc.log | \
zeek-cut ts id.orig_h id.resp_h operation | \
grep -i "wbem\|wmi" | sort | uniq -c | sort -rn
# Detect RDP connections between internal hosts
cat /opt/zeek/logs/current/conn.log | \
zeek-cut ts id.orig_h id.resp_h id.resp_p duration | \
awk '$4 == 3389 && $5 > 60' | \
sort -t$'\t' -k2 | head -20
# Detect Kerberos ticket-granting anomalies
cat /opt/zeek/logs/current/kerberos.log | \
zeek-cut ts id.orig_h id.resp_h client service success error_msg | \
grep -v "true" | head -20
# Custom Zeek script for lateral movement detection
sudo tee /opt/zeek/share/zeek/site/custom-detections/lateral-movement.zeek << 'ZEEKEOF'
@load base/frameworks/notice
@load base/frameworks/sumstats
module LateralMovement;
export {
redef enum Notice::Type += {
SMB_Lateral_Spread,
RDP_Lateral_Chain
};
const smb_host_threshold: count = 5 &redef;
const smb_time_window: interval = 15min &redef;
}
event zeek_init()
{
local r1 = SumStats::Reducer(
$stream="lateral.smb",
$apply=set(SumStats::UNIQUE)
);
SumStats::create([
$name="detect-smb-lateral",
$epoch=smb_time_window,
$reducers=set(r1),
$threshold_val(key: SumStats::Key, result: SumStats::Result) = {
return result["lateral.smb"]$unique + 0.0;
},
$threshold=smb_host_threshold + 0.0,
$threshold_crossed(key: SumStats::Key, result: SumStats::Result) = {
NOTICE([
$note=SMB_Lateral_Spread,
$msg=fmt("Host %s connected to %d SMB hosts in %s",
key$str, result["lateral.smb"]$unique, smb_time_window),
$identifier=key$str
]);
}
]);
}
event connection_state_remove(c: connection)
{
if ( c$id$resp_p == 445/tcp && c$id$resp_h in Site::local_nets )
{
SumStats::observe("lateral.smb",
[$str=cat(c$id$orig_h)],
[$str=cat(c$id$resp_h)]
);
}
}
ZEEKEOF
sudo zeekctl deploy
Step 4: Threat Hunting for Lateral Movement Indicators
# Hunt for authentication anomalies in Windows logs
# Splunk query: Users authenticating from unusual source hosts
# index=wineventlog EventCode=4624 LogonType=3
# | stats values(IpAddress) as source_ips dc(IpAddress) as source_count by TargetUserName
# | where source_count > 5
# | sort -source_count
# Hunt for service accounts used interactively
# index=wineventlog EventCode=4624 (LogonType=2 OR LogonType=10)
# | where match(TargetUserName, "^svc-.*")
# | table _time ComputerName TargetUserName IpAddress LogonType
# Network flow analysis for lateral movement patterns
# Look for hosts that suddenly start communicating with many internal hosts
cat /opt/zeek/logs/current/conn.log | \
zeek-cut ts id.orig_h id.resp_h | \
awk '{
key = $2
targets[key][$3] = 1
}
END {
for (src in targets) {
count = 0
for (dst in targets[src]) count++
if (count > 20) print src, count
}
}' | sort -k2 -rn
# Detect credential dumping artifacts (large LSASS reads)
# Look for connections from hosts that suddenly pivot
cat /opt/zeek/logs/current/conn.log | \
zeek-cut ts id.orig_h id.resp_h id.resp_p orig_bytes | \
awk '$4 == 445 && $5 > 10000000' | sort -t$'\t' -k5 -rn
# Timeline analysis: map the attack path
# index=wineventlog (EventCode=4624 OR EventCode=7045)
# | eval stage=case(
# EventCode=4624 AND LogonType=3, "Network Logon",
# EventCode=4624 AND LogonType=10, "RDP Logon",
# EventCode=7045, "Service Creation"
# )
# | timechart span=5m count by stage
Step 5: Automated Response and Containment
# SOAR playbook for lateral movement response (pseudocode)
# When lateral movement alert triggers:
# 1. Enrich the alert with context
# - Query AD for user group membership and role
# - Check if source IP is a known admin workstation
# - Look up recent vulnerability scan results for affected hosts
# 2. Automated containment actions
# Option A: Isolate the host via switch port shutdown
# ssh admin@switch "conf t; interface Gi1/0/5; shutdown"
# Option B: Quarantine via VLAN change (less disruptive)
# ssh admin@switch "conf t; interface Gi1/0/5; switchport access vlan 999"
# Option C: Block at firewall
sudo iptables -I FORWARD -s 10.10.5.23 -j DROP
# 3. Disable the compromised account
# PowerShell: Disable-ADAccount -Identity compromised_user
# 4. Force password reset
# PowerShell: Set-ADAccountPassword -Identity compromised_user -Reset
# 5. Collect forensic evidence before full containment
# velociraptor artifact collect Windows.KapeFiles.Targets --target BasicCollection
Step 6: Build Detection Dashboard
# Elastic Kibana dashboard queries for lateral movement monitoring
# Panel 1: Authentication heatmap (source vs destination)
# Aggregation: Terms on source.ip (rows) and destination.ip (columns)
# Metric: Count of event.code:4624
# Panel 2: SMB connections between internal hosts
# Filter: destination.port:445 and source.ip:10.0.0.0/8
# Aggregation: Top 20 source IPs by unique destination count
# Panel 3: RDP sessions timeline
# Filter: destination.port:3389 and event.code:4624 and winlog.event_data.LogonType:10
# Visualization: Timeline by source.ip
# Panel 4: New service installations
# Filter: event.code:7045
# Aggregation: Terms on winlog.event_data.ServiceName
# Panel 5: Failed authentication spike detection
# Filter: event.code:4625
# Aggregation: Date histogram with anomaly detection
# Export Kibana dashboard
# curl -X GET "elastic-siem:5601/api/saved_objects/_export" \
# -H "kbn-xsrf: true" \
# -d '{"type":"dashboard","objects":[{"id":"lateral-movement-dashboard","type":"dashboard"}]}' \
# > lateral_movement_dashboard.ndjson
Key Concepts
| Term | Definition |
|---|---|
| Lateral Movement | MITRE ATT&CK tactic (TA0008) describing techniques attackers use to move through a network from one compromised system to another |
| Pass-the-Hash (T1550.002) | Using captured NTLM password hashes to authenticate to remote systems without knowing the plaintext password |
| PsExec (T1569.002) | Remote service execution tool that creates a temporary service on the target system, detectable by Event ID 7045 |
| East-West Traffic | Network communication between internal systems (as opposed to north-south traffic between internal and external networks) |
| Authentication Anomaly | Deviation from baseline authentication patterns such as a user logging into systems they never accessed before |
| Kerberoasting (T1558.003) | Requesting Kerberos service tickets for service accounts and cracking them offline, detectable via Event ID 4769 anomalies |
Tools & Systems
- Zeek: Network security monitor generating SMB, Kerberos, DCE-RPC, and connection logs for lateral movement analysis
- Splunk/Elastic SIEM: Log aggregation platforms for correlating authentication events, network flows, and service creation across the enterprise
- Sigma: Vendor-agnostic detection rule format for writing portable lateral movement detection rules across SIEM platforms
- Velociraptor: Endpoint forensics tool for collecting evidence from hosts involved in lateral movement chains
- BloodHound: Active Directory attack path analysis tool for identifying potential lateral movement routes before attackers exploit them
Common Scenarios
Scenario: Detecting a Ransomware Operator's Lateral Movement
Context: The SOC receives an alert for PsExec service creation on a file server (10.10.20.15) at 2:00 AM. The alert triggers a lateral movement investigation. The organization has Zeek network monitoring and Windows Event Log forwarding to Splunk.
Approach:
- Query Splunk for Event ID 7045 (service creation) on 10.10.20.15 to confirm PsExec execution and identify the source IP (10.10.5.23)
- Trace authentication history for 10.10.5.23: find Event ID 4624 Type 3 logons, discovering the host authenticated to 8 servers in the past hour using NTLM (pass-the-hash pattern)
- Check Zeek conn.log for 10.10.5.23: identify SMB connections (port 445) to 12 internal hosts and large file transfers to an external IP
- Build the attack timeline: initial compromise via phishing at 1:15 AM, credential dumping at 1:25 AM, lateral movement to 8 servers between 1:30-2:00 AM
- Identify all compromised hosts by tracing authentication chains: 10.10.5.23 -> 10.10.20.15 -> 10.10.20.16 -> 10.10.20.17
- Contain by quarantining all identified hosts to VLAN 999, disabling the compromised account, and blocking the external C2 IP
- Report the complete attack chain with timeline, affected hosts, and detection gaps
Pitfalls:
- Only investigating the single alert instead of tracing the full lateral movement chain across all hosts
- Not checking for persistence mechanisms on each compromised host before declaring containment
- Relying solely on Windows Event Logs without correlating network flow data, missing lateral movement via tools that do not generate Windows events
- Not establishing a baseline of normal internal authentication patterns, making anomaly detection impossible
Output Format
## Lateral Movement Investigation Report
**Case ID**: IR-2024-0312
**Initial Alert**: PsExec on 10.10.20.15 at 02:00 UTC
**Investigation Period**: 2024-03-15 01:00 to 03:00 UTC
### Attack Timeline
| Time (UTC) | Source | Destination | Technique | Evidence |
|------------|--------|-------------|-----------|----------|
| 01:15 | External | 10.10.5.23 | Initial Access (Phishing) | Email log + HTTP download |
| 01:25 | 10.10.5.23 | Local | Credential Dumping | LSASS access (Sysmon EID 10) |
| 01:32 | 10.10.5.23 | 10.10.20.15 | Pass-the-Hash (SMB) | EID 4624 Type 3 NTLM |
| 01:38 | 10.10.5.23 | 10.10.20.16 | PsExec | EID 7045 + Zeek SMB |
| 01:45 | 10.10.20.16 | 10.10.20.17 | RDP | EID 4624 Type 10 |
| 02:00 | 10.10.20.17 | 10.10.20.15 | PsExec (triggered alert) | EID 7045 |
| 02:10 | 10.10.5.23 | 203.0.113.50 | Data Exfiltration | Zeek conn.log 2.3 GB |
### Affected Systems
- 10.10.5.23 (workstation-045) - Initial compromise
- 10.10.20.15 (file-server-01) - Data accessed
- 10.10.20.16 (app-server-02) - Pivoted through
- 10.10.20.17 (db-server-01) - Final target
### Detection Gaps
1. Initial phishing email not blocked by email gateway
2. Credential dumping not detected (no LSASS monitoring)
3. 30-minute gap between first lateral movement and alert