Techniques

Adversaries may gain access into industrial environments through systems exposed directly to the internet for remote access rather than through External Remote Services. Internet Accessible Devices are exposed to the internet unintentionally or intentionally without adequate protections. This may allow for adversaries to move directly into the control system network. Access onto these devices is accomplished without the use of exploits, these would be represented within the Exploit Public-Facing Application technique.

Adversaries may leverage built in functions for remote access which may not be protected or utilize minimal legacy protections that may be targeted. [1] These services may be discoverable through the use of online scanning tools.

In the case of the Bowman dam incident, adversaries leveraged access to the dam control network through a cellular modem. Access to the device was protected by password authentication, although the application was vulnerable to brute forcing. [1] [2] [3]

In Trend Micros manufacturing deception operations adversaries were detected leveraging direct internet access to an ICS environment through the exposure of operational protocols such as Siemens S7, Omron FINS, and EtherNet/IP, in addition to misconfigured VNC access. [4]

Firmware is low-level software embedded in hardware that enables systems and devices to function properly and is commonly found in ICS environments. Adversaries may modify firmware on a system or device by installing malicious or vulnerable versions that enable them to achieve objectives such as Persistence, Impair Process Control, and Inhibit Response Function.

Adversaries may modify system and device firmware by using the built-in firmware update functionality which may support local or remote installation. The malicious or vulnerable firmware may be delivered via Replication Through Removable Media, Supply Chain Compromise, or Remote Services. Once installed, the malicious or vulnerable firmware could be used to provide Rootkit and Hooking functionality, Exploitation for Privilege Escalation, or Denial of Service.[1]

Adversaries may gather information about the victim's network security appliances that can be used during targeting. Information about network security appliances may include a variety of details, such as the existence and specifics of deployed firewalls, content filters, and proxies/bastion hosts. Adversaries may also target information about victim network-based intrusion detection systems (NIDS) or other appliances related to defensive cybersecurity operations.

Adversaries may gather this information in various ways, such as direct collection actions via Active Scanning or Phishing for Information.[1] Information about network security appliances may also be exposed to adversaries via online or other accessible data sets (ex: Search Victim-Owned Websites). Gathering this information may reveal opportunities for other forms of reconnaissance (ex: Search Open Technical Databases or Search Open Websites/Domains), establishing operational resources (ex: Develop Capabilities or Obtain Capabilities), and/or initial access (ex: External Remote Services).

Adversaries may gather information about the victim's network topology that can be used during targeting. Information about network topologies may include a variety of details, including the physical and/or logical arrangement of both external-facing and internal network environments. This information may also include specifics regarding network devices (gateways, routers, etc.) and other infrastructure.

Adversaries may gather this information in various ways, such as direct collection actions via Active Scanning or Phishing for Information. Information about network topologies may also be exposed to adversaries via online or other accessible data sets (ex: Search Victim-Owned Websites).[1] Gathering this information may reveal opportunities for other forms of reconnaissance (ex: Search Open Technical Databases or Search Open Websites/Domains), establishing operational resources (ex: Acquire Infrastructure or Compromise Infrastructure), and/or initial access (ex: External Remote Services).

Adversaries may perform a port scan on a system, device, or network to identify live hosts, enumerate open ports and running services, identify operating systems, and map out the network.[1] The results of a port scan may inform adversary Discovery, Lateral Movement, and vulnerability exploitation decisions (Exploitation for Evasion, Exploitation for Privilege Escalation, Exploitation of Remote Services).

Some common tools for executing a port scan include `nmap`, `netcat`, and the Advanced Port Scanner.

Adversaries may search for private key certificate files on compromised systems for insecurely stored credentials. Private cryptographic keys and certificates are used for authentication, encryption/decryption, and digital signatures.[1] Common key and certificate file extensions include: .key, .pgp, .gpg, .ppk., .p12, .pem, .pfx, .cer, .p7b, .asc.

Adversaries may also look in common key directories, such as ~/.ssh for SSH keys on * nix-based systems or C:\Users\(username)\.ssh\ on Windows. Adversary tools may also search compromised systems for file extensions relating to cryptographic keys and certificates.[2][3]

When a device is registered to Entra ID, a device key and a transport key are generated and used to verify the device’s identity.[4] An adversary with access to the device may be able to export the keys in order to impersonate the device.[5]

On network devices, private keys may be exported via Network Device CLI commands such as `crypto pki export`.[6]

Some private keys require a password or passphrase for operation, so an adversary may also use Input Capture for keylogging or attempt to Brute Force the passphrase off-line. These private keys can be used to authenticate to Remote Services like SSH or for use in decrypting other collected files such as email.

Adversaries may purchase technical information about victims that can be used during targeting. Information about victims may be available for purchase within reputable private sources and databases, such as paid subscriptions to feeds of scan databases or other data aggregation services. Adversaries may also purchase information from less-reputable sources such as dark web or cybercrime blackmarkets.

Adversaries may purchase information about their already identified targets, or use purchased data to discover opportunities for successful breaches. Threat actors may gather various technical details from purchased data, including but not limited to employee contact information, credentials, or specifics regarding a victim’s infrastructure.[1] Information from these sources may reveal opportunities for other forms of reconnaissance (ex: Phishing for Information or Search Open Websites/Domains), establishing operational resources (ex: Develop Capabilities or Obtain Capabilities), and/or initial access (ex: External Remote Services or Valid Accounts).

Adversaries may take control of preexisting sessions with remote services to move laterally in an environment. Users may use valid credentials to log into a service specifically designed to accept remote connections, such as telnet, SSH, and RDP. When a user logs into a service, a session will be established that will allow them to maintain a continuous interaction with that service.

Adversaries may commandeer these sessions to carry out actions on remote systems. Remote Service Session Hijacking differs from use of Remote Services because it hijacks an existing session rather than creating a new session using Valid Accounts.[1][2]

Adversaries may use Valid Accounts to log into a service that accepts remote connections, such as telnet, SSH, and VNC. The adversary may then perform actions as the logged-on user.

In an enterprise environment, servers and workstations can be organized into domains. Domains provide centralized identity management, allowing users to login using one set of credentials across the entire network. If an adversary is able to obtain a set of valid domain credentials, they could login to many different machines using remote access protocols such as secure shell (SSH) or remote desktop protocol (RDP).[1][2] They could also login to accessible SaaS or IaaS services, such as those that federate their identities to the domain, or management platforms for internal virtualization environments such as VMware vCenter.

Legitimate applications (such as Software Deployment Tools and other administrative programs) may utilize Remote Services to access remote hosts. For example, Apple Remote Desktop (ARD) on macOS is native software used for remote management. ARD leverages a blend of protocols, including VNC to send the screen and control buffers and SSH for secure file transfer.[3][4][5] Adversaries can abuse applications such as ARD to gain remote code execution and perform lateral movement. In versions of macOS prior to 10.14, an adversary can escalate an SSH session to an ARD session which enables an adversary to accept TCC (Transparency, Consent, and Control) prompts without user interaction and gain access to data.[6][7][4]

Adversaries may leverage remote services to move between assets and network segments. These services are often used to allow operators to interact with systems remotely within the network, some examples are RDP, SMB, SSH, and other similar mechanisms. [1] [2] [3]

Remote services could be used to support remote access, data transmission, authentication, name resolution, and other remote functions. Further, remote services may be necessary to allow operators and administrators to configure systems within the network from their engineering or management workstations. An adversary may use this technique to access devices which may be dual-homed [1] to multiple network segments, and can be used for Program Download or to execute attacks on control devices directly through Valid Accounts.

Specific remote services (RDP & VNC) may be a precursor to enable Graphical User Interface execution on devices such as HMIs or engineering workstation software.

Based on incident data, CISA and FBI assessed that Chinese state-sponsored actors also compromised various authorized remote access channels, including systems designed to transfer data and/or allow access between corporate and ICS networks. [4]

Adversaries may use SID-History Injection to escalate privileges and bypass access controls. The Windows security identifier (SID) is a unique value that identifies a user or group account. SIDs are used by Windows security in both security descriptors and access tokens. [1] An account can hold additional SIDs in the SID-History Active Directory attribute [2], allowing inter-operable account migration between domains (e.g., all values in SID-History are included in access tokens).

With Domain Administrator (or equivalent) rights, harvested or well-known SID values [3] may be inserted into SID-History to enable impersonation of arbitrary users/groups such as Enterprise Administrators. This manipulation may result in elevated access to local resources and/or access to otherwise inaccessible domains via lateral movement techniques such as Remote Services, SMB/Windows Admin Shares, or Windows Remote Management.

Adversaries may search within public scan databases for information about victims that can be used during targeting. Various online services continuously publish the results of Internet scans/surveys, often harvesting information such as active IP addresses, hostnames, open ports, certificates, and even server banners.[1]

Adversaries may search scan databases to gather actionable information. Threat actors can use online resources and lookup tools to harvest information from these services. Adversaries may seek information about their already identified targets, or use these datasets to discover opportunities for successful breaches. Information from these sources may reveal opportunities for other forms of reconnaissance (ex: Active Scanning or Search Open Websites/Domains), establishing operational resources (ex: Develop Capabilities or Obtain Capabilities), and/or initial access (ex: External Remote Services or Exploit Public-Facing Application).

Adversaries may scan victim IP blocks to gather information that can be used during targeting. Public IP addresses may be allocated to organizations by block, or a range of sequential addresses.

Adversaries may scan IP blocks in order to Gather Victim Network Information, such as which IP addresses are actively in use as well as more detailed information about hosts assigned these addresses. Scans may range from simple pings (ICMP requests and responses) to more nuanced scans that may reveal host software/versions via server banners or other network artifacts.[1] Information from these scans may reveal opportunities for other forms of reconnaissance (ex: Search Open Websites/Domains or Search Open Technical Databases), establishing operational resources (ex: Develop Capabilities or Obtain Capabilities), and/or initial access (ex: External Remote Services).

Adversaries may search and gather information about victims from closed (e.g., paid, private, or otherwise not freely available) sources that can be used during targeting. Information about victims may be available for purchase from reputable private sources and databases, such as paid subscriptions to feeds of technical/threat intelligence data. Adversaries may also purchase information from less-reputable sources such as dark web or cybercrime blackmarkets.[1]

Adversaries may search in different closed databases depending on what information they seek to gather. Information from these sources may reveal opportunities for other forms of reconnaissance (ex: Phishing for Information or Search Open Websites/Domains), establishing operational resources (ex: Develop Capabilities or Obtain Capabilities), and/or initial access (ex: External Remote Services or Valid Accounts).

Adversaries may search freely available technical databases for information about victims that can be used during targeting. Information about victims may be available in online databases and repositories, such as registrations of domains/certificates as well as public collections of network data/artifacts gathered from traffic and/or scans.[1][2][3][4][5][6][7]

Adversaries may search in different open databases depending on what information they seek to gather. Information from these sources may reveal opportunities for other forms of reconnaissance (ex: Phishing for Information or Search Open Websites/Domains), establishing operational resources (ex: Acquire Infrastructure or Compromise Infrastructure), and/or initial access (ex: External Remote Services or Trusted Relationship).

Adversaries may search freely available websites and/or domains for information about victims that can be used during targeting. Information about victims may be available in various online sites, such as social media, new sites, or those hosting information about business operations such as hiring or requested/rewarded contracts.[1][2][3]

Adversaries may search in different online sites depending on what information they seek to gather. Information from these sources may reveal opportunities for other forms of reconnaissance (ex: Phishing for Information or Search Open Technical Databases), establishing operational resources (ex: Establish Accounts or Compromise Accounts), and/or initial access (ex: External Remote Services or Phishing).

Adversaries may gather information about the victim's host software that can be used during targeting. Information about installed software may include a variety of details such as types and versions on specific hosts, as well as the presence of additional components that might be indicative of added defensive protections (ex: antivirus, SIEMs, etc.).

Adversaries may gather this information in various ways, such as direct collection actions via Active Scanning (ex: listening ports, server banners, user agent strings) or Phishing for Information. Adversaries may also compromise sites then include malicious content designed to collect host information from visitors.[1] Information about the installed software may also be exposed to adversaries via online or other accessible data sets (ex: job postings, network maps, assessment reports, resumes, or purchase invoices). Additionally, adversaries may analyze metadata from victim-owned files (e.g., PDFs, DOCs, images, and sound files hosted on victim-owned websites) to extract information about the software and hardware used to create or process those files. Metadata may reveal software versions, configurations, or timestamps that indicate outdated or vulnerable software. This information can be cross-referenced with known CVEs to identify potential vectors for exploitation in future operations.[2]

Gathering this information may reveal opportunities for other forms of reconnaissance (ex: Search Open Websites/Domains or Search Open Technical Databases), establishing operational resources (ex: Develop Capabilities or Obtain Capabilities), and/or for initial access (ex: Supply Chain Compromise or External Remote Services).

Adversaries may search private data from threat intelligence vendors for information that can be used during targeting. Threat intelligence vendors may offer paid feeds or portals that offer more data than what is publicly reported. Although sensitive details (such as customer names and other identifiers) may be redacted, this information may contain trends regarding breaches such as target industries, attribution claims, and successful TTPs/countermeasures.[1]

Adversaries may search in private threat intelligence vendor data to gather actionable information. If a threat actor is searching for information on their own activities, that falls under Search Threat Vendor Data. Information reported by vendors may also reveal opportunities other forms of reconnaissance (ex: Search Open Websites/Domains), establishing operational resources (ex: Develop Capabilities or Obtain Capabilities), and/or initial access (ex: Exploit Public-Facing Application or External Remote Services).

Adversaries may search public WHOIS data for information about victims that can be used during targeting. WHOIS data is stored by regional Internet registries (RIR) responsible for allocating and assigning Internet resources such as domain names. Anyone can query WHOIS servers for information about a registered domain, such as assigned IP blocks, contact information, and DNS nameservers.[1]

Adversaries may search WHOIS data to gather actionable information. Threat actors can use online resources or command-line utilities to pillage through WHOIS data for information about potential victims. Information from these sources may reveal opportunities for other forms of reconnaissance (ex: Active Scanning or Phishing for Information), establishing operational resources (ex: Acquire Infrastructure or Compromise Infrastructure), and/or initial access (ex: External Remote Services or Trusted Relationship).

Adversaries may install code on externally facing portals, such as a VPN login page, to capture and transmit credentials of users who attempt to log into the service. For example, a compromised login page may log provided user credentials before logging the user in to the service.

This variation on input capture may be conducted post-compromise using legitimate administrative access as a backup measure to maintain network access through External Remote Services and Valid Accounts or as part of the initial compromise by exploitation of the externally facing web service.[1]

Adversaries may abuse the Windows command shell for execution. The Windows command shell (cmd) is the primary command prompt on Windows systems. The Windows command prompt can be used to control almost any aspect of a system, with various permission levels required for different subsets of commands. The command prompt can be invoked remotely via Remote Services such as SSH.[1]

Batch files (ex: .bat or .cmd) also provide the shell with a list of sequential commands to run, as well as normal scripting operations such as conditionals and loops. Common uses of batch files include long or repetitive tasks, or the need to run the same set of commands on multiple systems.

Adversaries may leverage cmd to execute various commands and payloads. Common uses include cmd to execute a single command, or abusing cmd interactively with input and output forwarded over a command and control channel.

Adversaries may disable or modify the Windows host firewall to bypass controls limiting network usage. This can include disabling the Windows host firewall entirely, suppressing specific profiles (domain, private, public), or adding, deleting, and modifying firewall rules to allow or restrict traffic.[1]

Adversaries may perform these modifications through multiple mechanisms depending on the Windows operating system and access level. For example, adversaries may use command-line utilities (e.g., `netsh advfirewall` or PowerShell cmdlets like `Set-NetFirewallProfile`, `New-NetFirewallRule`), Windows Registry modifications (e.g., altering firewall states and rule configurations via registry keys), or the Windows Control Panel to modify firewall settings through the Windows Security interface.

By disabling or modifying Windows firewall services, adversaries may enable access to remote services, open ports for command and control traffic, or configure rules for further actions.

Adversaries may abuse Windows Management Instrumentation (WMI) to execute malicious commands and payloads. WMI is designed for programmers and is the infrastructure for management data and operations on Windows systems.[1] WMI is an administration feature that provides a uniform environment to access Windows system components.

The WMI service enables both local and remote access, though the latter is facilitated by Remote Services such as Distributed Component Object Model and Windows Remote Management.[1] Remote WMI over DCOM operates using port 135, whereas WMI over WinRM operates over port 5985 when using HTTP and 5986 for HTTPS.[1] [2]

An adversary can use WMI to interact with local and remote systems and use it as a means to execute various behaviors, such as gathering information for Discovery as well as Execution of commands and payloads.[2] For example, `wmic.exe` can be abused by an adversary to delete shadow copies with the command `wmic.exe Shadowcopy Delete` (i.e., Inhibit System Recovery).[3]

**Note:** `wmic.exe` is deprecated as of January of 2024, with the WMIC feature being “disabled by default” on Windows 11+. WMIC will be removed from subsequent Windows releases and replaced by PowerShell as the primary WMI interface.[4] In addition to PowerShell and tools like `wbemtool.exe`, COM APIs can also be used to programmatically interact with WMI via C++, .NET, VBScript, etc.[4]