Enterprise sub-techniques

Adversaries may target the different network services provided by systems to conduct a denial of service (DoS). Adversaries often target the availability of DNS and web services, however others have been targeted as well.[1] Web server software can be attacked through a variety of means, some of which apply generally while others are specific to the software being used to provide the service.

One example of this type of attack is known as a simple HTTP flood, where an adversary sends a large number of HTTP requests to a web server to overwhelm it and/or an application that runs on top of it. This flood relies on raw volume to accomplish the objective, exhausting any of the various resources required by the victim software to provide the service.[2]

Another variation, known as a SSL renegotiation attack, takes advantage of a protocol feature in SSL/TLS. The SSL/TLS protocol suite includes mechanisms for the client and server to agree on an encryption algorithm to use for subsequent secure connections. If SSL renegotiation is enabled, a request can be made for renegotiation of the crypto algorithm. In a renegotiation attack, the adversary establishes a SSL/TLS connection and then proceeds to make a series of renegotiation requests. Because the cryptographic renegotiation has a meaningful cost in computation cycles, this can cause an impact to the availability of the service when done in volume.[3]

Adversaries may execute their own malicious payloads by hijacking the binaries used by services. Adversaries may use flaws in the permissions of Windows services to replace the binary that is executed upon service start. These service processes may automatically execute specific binaries as part of their functionality or to perform other actions. If the permissions on the file system directory containing a target binary, or permissions on the binary itself are improperly set, then the target binary may be overwritten with another binary using user-level permissions and executed by the original process. If the original process and thread are running under a higher permissions level, then the replaced binary will also execute under higher-level permissions, which could include SYSTEM.

Adversaries may use this technique to replace legitimate binaries with malicious ones as a means of executing code at a higher permissions level. If the executing process is set to run at a specific time or during a certain event (e.g., system bootup) then this technique can also be used for persistence.

Adversaries may execute their own malicious payloads by hijacking the Registry entries used by services. Flaws in the permissions for Registry keys related to services can allow adversaries to redirect the originally specified executable to one they control, launching their own code when a service starts. Windows stores local service configuration information in the Registry under HKLM\SYSTEM\CurrentControlSet\Services. The information stored under a service's Registry keys can be manipulated to modify a service's execution parameters through tools such as the service controller, sc.exe, PowerShell, or Reg. Access to Registry keys is controlled through access control lists and user permissions. [1][2]

If the permissions for users and groups are not properly set and allow access to the Registry keys for a service, adversaries may change the service's binPath/ImagePath to point to a different executable under their control. When the service starts or is restarted, the adversary-controlled program will execute, allowing the adversary to establish persistence and/or privilege escalation to the account context the service is set to execute under (local/domain account, SYSTEM, LocalService, or NetworkService).

Adversaries may also alter other Registry keys in the service’s Registry tree. For example, the FailureCommand key may be changed so that the service is executed in an elevated context anytime the service fails or is intentionally corrupted.[3][4]

The Performance key contains the name of a driver service's performance DLL and the names of several exported functions in the DLL.[5] If the Performance key is not already present and if an adversary-controlled user has the Create Subkey permission, adversaries may create the Performance key in the service’s Registry tree to point to a malicious DLL.[6]

Adversaries may also add the Parameters key, which can reference malicious drivers file paths. This technique has been identified to be a method of abuse by configuring DLL file paths within the Parameters key of a given services registry configuration. By placing and configuring the Parameters key to reference a malicious DLL, adversaries can ensure that their code is loaded persistently whenever the associated service or library is invoked.

For example, the registry path[7] HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\WinSock2\Parameters[8][9] contains the AutodiaDLL value, which specifies the DLL to be loaded for autodial funcitionality. An adversary could set the AutodiaDLL to point to a hijacked or malicious DLL:

"AutodialDLL"="c:\temp\foo.dll"

This ensures persistence, as it causes the DLL (in this case, foo.dll) to be loaded each time the Winsock 2 library is invoked.

An adversary may abuse configurations where an application has the setuid or setgid bits set in order to get code running in a different (and possibly more privileged) user’s context. On Linux or macOS, when the setuid or setgid bits are set for an application binary, the application will run with the privileges of the owning user or group respectively.[1] Normally an application is run in the current user’s context, regardless of which user or group owns the application. However, there are instances where programs need to be executed in an elevated context to function properly, but the user running them may not have the specific required privileges.

Instead of creating an entry in the sudoers file, which must be done by root, any user can specify the setuid or setgid flag to be set for their own applications (i.e. Linux and Mac Permissions). The chmod command can set these bits with bitmasking, chmod 4777 [file] or via shorthand naming, chmod u+s [file]. This will enable the setuid bit. To enable the setgid bit, chmod 2775 and chmod g+s can be used.

Adversaries can use this mechanism on their own malware to make sure they're able to execute in elevated contexts in the future.[2] This abuse is often part of a "shell escape" or other actions to bypass an execution environment with restricted permissions.

Alternatively, adversaries may choose to find and target vulnerable binaries with the setuid or setgid bits already enabled (i.e. File and Directory Discovery). The setuid and setguid bits are indicated with an "s" instead of an "x" when viewing a file's attributes via ls -l. The find command can also be used to search for such files. For example, find / -perm +4000 2>/dev/null can be used to find files with setuid set and find / -perm +2000 2>/dev/null may be used for setgid. Binaries that have these bits set may then be abused by adversaries.[3]

Adversaries may leverage the SharePoint repository as a source to mine valuable information. SharePoint will often contain useful information for an adversary to learn about the structure and functionality of the internal network and systems. For example, the following is a list of example information that may hold potential value to an adversary and may also be found on SharePoint:

* Policies, procedures, and standards * Physical / logical network diagrams * System architecture diagrams * Technical system documentation * Testing / development credentials (i.e., Unsecured Credentials) * Work / project schedules * Source code snippets * Links to network shares and other internal resources

Adversaries may search the command history on compromised systems for insecurely stored credentials.

On Linux and macOS systems, shells such as Bash and Zsh keep track of the commands users type on the command-line with the "history" utility. Once a user logs out, the history is flushed to the user's history file. For each user, this file resides at the same location: for example, `~/.bash_history` or `~/.zsh_history`. Typically, these files keeps track of the user's last 1000 commands.

On Windows, PowerShell has both a command history that is wiped after the session ends, and one that contains commands used in all sessions and is persistent. The default location for persistent history can be found in `%userprofile%\AppData\Roaming\Microsoft\Windows\PowerShell\PSReadline\ConsoleHost_history.txt`, but command history can also be accessed with `Get-History`. Command Prompt (CMD) on Windows does not have persistent history.[1][2]

Users often type usernames and passwords on the command-line as parameters to programs, which then get saved to this file when they log out. Adversaries can abuse this by looking through the file for potential credentials.[3]

Adversaries may create or modify shortcuts that can execute a program during system boot or user login. Shortcuts or symbolic links are used to reference other files or programs that will be opened or executed when the shortcut is clicked or executed by a system startup process.

Adversaries may abuse shortcuts in the startup folder to execute their tools and achieve persistence.[1] Although often used as payloads in an infection chain (e.g. Spearphishing Attachment), adversaries may also create a new shortcut as a means of indirection, while also abusing Masquerading to make the malicious shortcut appear as a legitimate program. Adversaries can also edit the target path or entirely replace an existing shortcut so their malware will be executed instead of the intended legitimate program.

Shortcuts can also be abused to establish persistence by implementing other methods. For example, LNK browser extensions may be modified (e.g. Browser Extensions) to persistently launch malware.

Adversaries who have the password hash of a target service account (e.g. SharePoint, MSSQL) may forge Kerberos ticket granting service (TGS) tickets, also known as silver tickets. Kerberos TGS tickets are also known as service tickets.[1]

Silver tickets are more limited in scope in than golden tickets in that they only enable adversaries to access a particular resource (e.g. MSSQL) and the system that hosts the resource; however, unlike golden tickets, adversaries with the ability to forge silver tickets are able to create TGS tickets without interacting with the Key Distribution Center (KDC), potentially making detection more difficult.[2]

Password hashes for target services may be obtained using OS Credential Dumping or Kerberoasting.

Adversaries may search social media for information about victims that can be used during targeting. Social media sites may contain various information about a victim organization, such as business announcements as well as information about the roles, locations, and interests of staff.

Adversaries may search in different social media sites depending on what information they seek to gather. Threat actors may passively harvest data from these sites, as well as use information gathered to create fake profiles/groups to elicit victim’s into revealing specific information (i.e. Spearphishing Service).[1] 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: Spearphishing via Service).

Adversaries may compromise social media accounts that can be used during targeting. For operations incorporating social engineering, the utilization of an online persona may be important. Rather than creating and cultivating social media profiles (i.e. Social Media Accounts), adversaries may compromise existing social media accounts. Utilizing an existing persona may engender a level of trust in a potential victim if they have a relationship, or knowledge of, the compromised persona.

A variety of methods exist for compromising social media accounts, such as gathering credentials via Phishing for Information, purchasing credentials from third-party sites, or by brute forcing credentials (ex: password reuse from breach credential dumps).[1] Prior to compromising social media accounts, adversaries may conduct Reconnaissance to inform decisions about which accounts to compromise to further their operation.

Personas may exist on a single site or across multiple sites (ex: Facebook, LinkedIn, Twitter, etc.). Compromised social media accounts may require additional development, this could include filling out or modifying profile information, further developing social networks, or incorporating photos.

Adversaries can use a compromised social media profile to create new, or hijack existing, connections to targets of interest. These connections may be direct or may include trying to connect through others.[2][3] Compromised profiles may be leveraged during other phases of the adversary lifecycle, such as during Initial Access (ex: Spearphishing via Service).

Adversaries may create and cultivate social media accounts that can be used during targeting. Adversaries can create social media accounts that can be used to build a persona to further operations. Persona development consists of the development of public information, presence, history and appropriate affiliations.[1][2]

For operations incorporating social engineering, the utilization of a persona on social media may be important. These personas may be fictitious or impersonate real people. The persona may exist on a single social media site or across multiple sites (ex: Facebook, LinkedIn, Twitter, etc.). Establishing a persona on social media may require development of additional documentation to make them seem real. This could include filling out profile information, developing social networks, or incorporating photos.

Once a persona has been developed an adversary can use it to create connections to targets of interest. These connections may be direct or may include trying to connect through others.[1][2] These accounts may be leveraged during other phases of the adversary lifecycle, such as during Initial Access (ex: Spearphishing via Service).

Adversaries may attach filters to a network socket to monitor then activate backdoors used for persistence or command and control. With elevated permissions, adversaries can use features such as the `libpcap` library to open sockets and install filters to allow or disallow certain types of data to come through the socket. The filter may apply to all traffic passing through the specified network interface (or every interface if not specified). When the network interface receives a packet matching the filter criteria, additional actions can be triggered on the host, such as activation of a reverse shell.

To establish a connection, an adversary sends a crafted packet to the targeted host that matches the installed filter criteria.[1] Adversaries have used these socket filters to trigger the installation of implants, conduct ping backs, and to invoke command shells. Communication with these socket filters may also be used in conjunction with Protocol Tunneling.[2][3]

Filters can be installed on any Unix-like platform with `libpcap` installed or on Windows hosts using `Winpcap`. Adversaries may use either `libpcap` with `pcap_setfilter` or the standard library function `setsockopt` with `SO_ATTACH_FILTER` options. Since the socket connection is not active until the packet is received, this behavior may be difficult to detect due to the lack of activity on a host, low CPU overhead, and limited visibility into raw socket usage.

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 perform software packing or virtual machine software protection to conceal their code. Software packing is a method of compressing or encrypting an executable. Packing an executable changes the file signature in an attempt to avoid signature-based detection. Most decompression techniques decompress the executable code in memory. Virtual machine software protection translates an executable's original code into a special format that only a special virtual machine can run. A virtual machine is then called to run this code.[1]

Utilities used to perform software packing are called packers. Example packers are MPRESS and UPX. A more comprehensive list of known packers is available, but adversaries may create their own packing techniques that do not leave the same artifacts as well-known packers to evade defenses.[2]

Adversaries can hide a program's true filetype by changing the extension of a file. With certain file types (specifically this does not work with .app extensions), appending a space to the end of a filename will change how the file is processed by the operating system.

For example, if there is a Mach-O executable file called evil.bin, when it is double clicked by a user, it will launch Terminal.app and execute. If this file is renamed to evil.txt, then when double clicked by a user, it will launch with the default text editing application (not executing the binary). However, if the file is renamed to evil.txt (note the space at the end), then when double clicked by a user, the true file type is determined by the OS and handled appropriately and the binary will be executed [1].

Adversaries can use this feature to trick users into double clicking benign-looking files of any format and ultimately executing something malicious.

Adversaries may send spearphishing emails with a malicious attachment in an attempt to gain access to victim systems. Spearphishing attachment is a specific variant of spearphishing. Spearphishing attachment is different from other forms of spearphishing in that it employs the use of malware attached to an email. All forms of spearphishing are electronically delivered social engineering targeted at a specific individual, company, or industry. In this scenario, adversaries attach a file to the spearphishing email and usually rely upon User Execution to gain execution.[1] Spearphishing may also involve social engineering techniques, such as posing as a trusted source.

There are many options for the attachment such as Microsoft Office documents, executables, PDFs, or archived files. Upon opening the attachment (and potentially clicking past protections), the adversary's payload exploits a vulnerability or directly executes on the user's system. The text of the spearphishing email usually tries to give a plausible reason why the file should be opened, and may explain how to bypass system protections in order to do so. The email may also contain instructions on how to decrypt an attachment, such as a zip file password, in order to evade email boundary defenses. Adversaries frequently manipulate file extensions and icons in order to make attached executables appear to be document files, or files exploiting one application appear to be a file for a different one.

Adversaries may send spearphishing messages with a malicious attachment to elicit sensitive information that can be used during targeting. Spearphishing for information is an attempt to trick targets into divulging information, frequently credentials or other actionable information. Spearphishing for information frequently involves social engineering techniques, such as posing as a source with a reason to collect information (ex: Establish Accounts or Compromise Accounts) and/or sending multiple, seemingly urgent messages.

All forms of spearphishing are electronically delivered social engineering targeted at a specific individual, company, or industry. In this scenario, adversaries attach a file to the spearphishing email. In some cases, they may rely upon the recipient populating information, then returning the file.[1][2] The text of the spearphishing email usually tries to give a plausible reason why the file should be filled-in, such as a request for information from a business associate. In other cases, adversaries may leverage techniques such as HTML Smuggling to harvest user credentials via fake login portals.[3]

Adversaries may also use information from previous reconnaissance efforts (ex: Search Open Websites/Domains or Search Victim-Owned Websites) to craft persuasive and believable lures.

Adversaries may send spearphishing emails with a malicious link in an attempt to gain access to victim systems. Spearphishing with a link is a specific variant of spearphishing. It is different from other forms of spearphishing in that it employs the use of links to download malware contained in email, instead of attaching malicious files to the email itself, to avoid defenses that may inspect email attachments. Spearphishing may also involve social engineering techniques, such as posing as a trusted source.

All forms of spearphishing are electronically delivered social engineering targeted at a specific individual, company, or industry. In this case, the malicious emails contain links. Generally, the links will be accompanied by social engineering text and require the user to actively click or copy and paste a URL into a browser, leveraging User Execution. The visited website may compromise the web browser using an exploit, or the user will be prompted to download applications, documents, zip files, or even executables depending on the pretext for the email in the first place.

Adversaries may also include links that are intended to interact directly with an email reader, including embedded images intended to exploit the end system directly. Additionally, adversaries may use seemingly benign links that abuse special characters to mimic legitimate websites (known as an "IDN homograph attack").[1] URLs may also be obfuscated by taking advantage of quirks in the URL schema, such as the acceptance of integer- or hexadecimal-based hostname formats and the automatic discarding of text before an “@” symbol: for example, `hxxp://google.com@1157586937`.[2]

Adversaries may also utilize links to perform consent phishing/spearphishing campaigns to Steal Application Access Tokens that grant immediate access to the victim environment. For example, a user may be lured into granting adversaries permissions/access via a malicious OAuth 2.0 request URL that when accepted by the user provide permissions/access for malicious applications.[3][4] These stolen access tokens allow the adversary to perform various actions on behalf of the user via API calls.[4]

Similarly, malicious links may also target device-based authorization, such as OAuth 2.0 device authorization grant flow which is typically used to authenticate devices without UIs/browsers. Known as “device code phishing,” an adversary may send a link that directs the victim to a malicious authorization page where the user is tricked into entering a code/credentials that produces a device token.[5][6][7]

Adversaries may send spearphishing messages with a malicious link to elicit sensitive information that can be used during targeting. Spearphishing for information is an attempt to trick targets into divulging information, frequently credentials or other actionable information. Spearphishing for information frequently involves social engineering techniques, such as posing as a source with a reason to collect information (ex: Establish Accounts or Compromise Accounts) and/or sending multiple, seemingly urgent messages.

All forms of spearphishing are electronically delivered social engineering targeted at a specific individual, company, or industry. In this scenario, the malicious emails contain links generally accompanied by social engineering text to coax the user to actively click or copy and paste a URL into a browser.[1][2] The given website may be a clone of a legitimate site (such as an online or corporate login portal) or may closely resemble a legitimate site in appearance and have a URL containing elements from the real site. URLs may also be obfuscated by taking advantage of quirks in the URL schema, such as the acceptance of integer- or hexadecimal-based hostname formats and the automatic discarding of text before an “@” symbol: for example, `hxxp://google.com@1157586937`.[3]

Adversaries may also embed “tracking pixels,” "web bugs," or "web beacons" within phishing messages to verify the receipt of an email, while also potentially profiling and tracking victim information such as IP address.[4][5] These mechanisms often appear as small images (typically one pixel in size) or otherwise obfuscated objects and are typically delivered as HTML code containing a link to a remote server.[5][6]

Adversaries may also be able to spoof a complete website using what is known as a "browser-in-the-browser" (BitB) attack. By generating a fake browser popup window with an HTML-based address bar that appears to contain a legitimate URL (such as an authentication portal), they may be able to prompt users to enter their credentials while bypassing typical URL verification methods.[7][8]

Adversaries can use phishing kits such as `EvilProxy` and `Evilginx2` to perform adversary-in-the-middle phishing by proxying the connection between the victim and the legitimate website. On a successful login, the victim is redirected to the legitimate website, while the adversary captures their session cookie (i.e., Steal Web Session Cookie) in addition to their username and password. This may enable the adversary to then bypass MFA via Web Session Cookie.[9]

Adversaries may also send a malicious link in the form of Quick Response (QR) Codes (also known as “quishing”). These links may direct a victim to a credential phishing page.[10] By using a QR code, the URL may not be exposed in the email and may thus go undetected by most automated email security scans.[11] These QR codes may be scanned by or delivered directly to a user’s mobile device (i.e., Phishing), which may be less secure in several relevant ways.[11] For example, mobile users may not be able to notice minor differences between genuine and credential harvesting websites due to mobile’s smaller form factor.

From the fake website, information is gathered in web forms and sent to the adversary. Adversaries may also use information from previous reconnaissance efforts (ex: Search Open Websites/Domains or Search Victim-Owned Websites) to craft persuasive and believable lures.

Adversaries may send spearphishing messages via third-party services to elicit sensitive information that can be used during targeting. Spearphishing for information is an attempt to trick targets into divulging information, frequently credentials or other actionable information. Spearphishing for information frequently involves social engineering techniques, such as posing as a source with a reason to collect information (ex: Establish Accounts or Compromise Accounts) and/or sending multiple, seemingly urgent messages.

All forms of spearphishing are electronically delivered social engineering targeted at a specific individual, company, or industry. In this scenario, adversaries send messages through various social media services, personal webmail, and other non-enterprise controlled services.[1] These services are more likely to have a less-strict security policy than an enterprise. As with most kinds of spearphishing, the goal is to generate rapport with the target or get the target's interest in some way. Adversaries may create fake social media accounts and message employees for potential job opportunities. Doing so allows a plausible reason for asking about services, policies, and information about their environment. Adversaries may also use information from previous reconnaissance efforts (ex: Social Media or Search Victim-Owned Websites) to craft persuasive and believable lures.

Adversaries may use voice communications to elicit sensitive information that can be used during targeting. Spearphishing for information is an attempt to trick targets into divulging information, frequently credentials or other actionable information. Spearphishing for information frequently involves social engineering techniques, such as posing as a source with a reason to collect information (ex: Impersonation) and/or creating a sense of urgency or alarm for the recipient.

All forms of phishing are electronically delivered social engineering. In this scenario, adversaries use phone calls to elicit sensitive information from victims. Known as voice phishing (or "vishing"), these communications can be manually executed by adversaries, hired call centers, or even automated via robocalls. Voice phishers may spoof their phone number while also posing as a trusted entity, such as a business partner or technical support staff.[1]

Victims may also receive phishing messages that direct them to call a phone number ("callback phishing") where the adversary attempts to collect confidential information.[2]

Adversaries may also use information from previous reconnaissance efforts (ex: Search Open Websites/Domains or Search Victim-Owned Websites) to tailor pretexts to be even more persuasive and believable for the victim.

Adversaries may use voice communications to ultimately gain access to victim systems. Spearphishing voice is a specific variant of spearphishing. It is different from other forms of spearphishing in that it employs the use of manipulating a user into providing access to systems through a phone call or other forms of voice communications. Spearphishing frequently involves social engineering techniques, such as posing as a trusted source (ex: Impersonation) and/or creating a sense of urgency or alarm for the recipient.

All forms of phishing are electronically delivered social engineering. In this scenario, adversaries are not directly sending malware to a victim vice relying on User Execution for delivery and execution. For example, victims may receive phishing messages that instruct them to call a phone number where they are directed to visit a malicious URL, download malware,[1][2] or install adversary-accessible remote management tools (Remote Access Tools) onto their computer.[3]

Adversaries may also combine voice phishing with Multi-Factor Authentication Request Generation in order to trick users into divulging MFA credentials or accepting authentication prompts.[4]

Adversaries may send spearphishing messages via third-party services in an attempt to gain access to victim systems. Spearphishing via service is a specific variant of spearphishing. It is different from other forms of spearphishing in that it employs the use of third party services rather than directly via enterprise email channels.

All forms of spearphishing are electronically delivered social engineering targeted at a specific individual, company, or industry. In this scenario, adversaries send messages through various social media services, personal webmail, and other non-enterprise controlled services.[1] These services are more likely to have a less-strict security policy than an enterprise. As with most kinds of spearphishing, the goal is to generate rapport with the target or get the target's interest in some way. Adversaries will create fake social media accounts and message employees for potential job opportunities. Doing so allows a plausible reason for asking about services, policies, and software that's running in an environment. The adversary can then send malicious links or attachments through these services.

A common example is to build rapport with a target via social media, then send content to a personal webmail service that the target uses on their work computer. This allows an adversary to bypass some email restrictions on the work account, and the target is more likely to open the file since it's something they were expecting. If the payload doesn't work as expected, the adversary can continue normal communications and troubleshoot with the target on how to get it working.

Adversaries may spoof security alerting from tools, presenting false evidence to impair defenders’ awareness of malicious activity.[1] Messages produced by defensive tools contain information about potential security events as well as the functioning status of security software and the system. Security reporting messages are important for monitoring the normal operation of a system and identifying important events that can signal a security incident.

Rather than or in addition to Indicator Blocking, an adversary can spoof positive affirmations that security tools are continuing to function even after legitimate security tools have been disabled (e.g., Disable or Modify Tools). An adversary can also present a “healthy” system status even after infection. This can be abused to enable further malicious activity by delaying defender responses.

For example, adversaries may show a fake Windows Security GUI and tray icon with a “healthy” system status after Windows Defender and other system tools have been disabled.[1]

Adversaries may encode data with a standard data encoding system to make the content of command and control traffic more difficult to detect. Command and control (C2) information can be encoded using a standard data encoding system that adheres to existing protocol specifications. Common data encoding schemes include ASCII, Unicode, hexadecimal, Base64, and MIME.[1][2] Some data encoding systems may also result in data compression, such as gzip.