Techniques

Adversaries may gather credential material by invoking or forcing a user to automatically provide authentication information through a mechanism in which they can intercept.

The Server Message Block (SMB) protocol is commonly used in Windows networks for authentication and communication between systems for access to resources and file sharing. When a Windows system attempts to connect to an SMB resource it will automatically attempt to authenticate and send credential information for the current user to the remote system.[1] This behavior is typical in enterprise environments so that users do not need to enter credentials to access network resources.

Web Distributed Authoring and Versioning (WebDAV) is also typically used by Windows systems as a backup protocol when SMB is blocked or fails. WebDAV is an extension of HTTP and will typically operate over TCP ports 80 and 443.[2][3]

Adversaries may take advantage of this behavior to gain access to user account hashes through forced SMB/WebDAV authentication. An adversary can send an attachment to a user through spearphishing that contains a resource link to an external server controlled by the adversary (i.e. Template Injection), or place a specially crafted file on navigation path for privileged accounts (e.g. .SCF file placed on desktop) or on a publicly accessible share to be accessed by victim(s). When the user's system accesses the untrusted resource, it will attempt authentication and send information, including the user's hashed credentials, over SMB to the adversary-controlled server.[4] With access to the credential hash, an adversary can perform off-line Brute Force cracking to gain access to plaintext credentials.[5]

There are several different ways this can occur.[6] Some specifics from in-the-wild use include:

* A spearphishing attachment containing a document with a resource that is automatically loaded when the document is opened (i.e. Template Injection). The document can include, for example, a request similar to file[:]//[remote address]/Normal.dotm to trigger the SMB request.[7] * A modified .LNK or .SCF file with the icon filename pointing to an external reference such as \\[remote address]\pic.png that will force the system to load the resource when the icon is rendered to repeatedly gather credentials.[7]

Alternatively, by leveraging the EfsRpcOpenFileRaw function, an adversary can send SMB requests to a remote system's MS-EFSRPC interface and force the victim computer to initiate an authentication procedure and share its authentication details. The Encrypting File System Remote Protocol (EFSRPC) is a protocol used in Windows networks for maintenance and management operations on encrypted data that is stored remotely to be accessed over a network. Utilization of EfsRpcOpenFileRaw function in EFSRPC is used to open an encrypted object on the server for backup or restore. Adversaries can collect this data and abuse it as part of a NTLM relay attack to gain access to remote systems on the same internal network.[8][9]

Adversaries may mimic common operating system GUI components to prompt users for credentials with a seemingly legitimate prompt. When programs are executed that need additional privileges than are present in the current user context, it is common for the operating system to prompt the user for proper credentials to authorize the elevated privileges for the task (ex: Bypass User Account Control).

Adversaries may mimic this functionality to prompt users for credentials with a seemingly legitimate prompt for a number of reasons that mimic normal usage, such as a fake installer requiring additional access or a fake malware removal suite.[1] This type of prompt can be used to collect credentials via various languages such as AppleScript[2][3][4] and PowerShell.[2][5][4] On Linux systems adversaries may launch dialog boxes prompting users for credentials from malicious shell scripts or the command line (i.e. Unix Shell).[4]

Adversaries may also mimic common software authentication requests, such as those from browsers or email clients. This may also be paired with user activity monitoring (i.e., Browser Information Discovery and/or Application Window Discovery) to spoof prompts when users are naturally accessing sensitive sites/data.

Adversaries may mimic common operating system GUI components to prompt users for sensitive information with a seemingly legitimate prompt. The operating system and installed applications often have legitimate needs to prompt the user for sensitive information such as account credentials, bank account information, or Personally Identifiable Information (PII). Compared to traditional PCs, the constrained display size of mobile devices may impair the ability to provide users with contextual information, making users more susceptible to this technique’s use.[1]

There are several approaches adversaries may use to mimic this functionality. Adversaries may impersonate the identity of a legitimate application (e.g. use the same application name and/or icon) and, when installed on the device, may prompt the user for sensitive information.[2] Adversaries may also send fake device notifications to the user that may trigger the display of an input prompt when clicked.[3]

Additionally, adversaries may display a prompt on top of a running, legitimate application to trick users into entering sensitive information into a malicious application rather than the legitimate application. Typically, adversaries need to know when the targeted application and the individual activity within the targeted application is running in the foreground to display the prompt at the proper time. Adversaries can abuse Android’s accessibility features to determine which application is currently in the foreground.[4] Two known approaches to displaying a prompt include:

* Adversaries start a new activity on top of a running legitimate application.[1][5] Android 10 places new restrictions on the ability for an application to start a new activity on top of another application, which may make it more difficult for adversaries to utilize this technique.[6] * Adversaries create an application overlay window on top of a running legitimate application. Applications must hold the `SYSTEM_ALERT_WINDOW` permission to create overlay windows. This permission is handled differently than typical Android permissions and, at least under certain conditions, is automatically granted to applications installed from the Google Play Store.[7][8][9] The `SYSTEM_ALERT_WINDOW` permission and its associated ability to create application overlay windows are expected to be deprecated in a future release of Android in favor of a new API.[10]

Adversaries may gather information about the victim's hosts that can be used during targeting. Information about hosts may include a variety of details, including administrative data (ex: name, assigned IP, functionality, etc.) as well as specifics regarding its configuration (ex: operating system, language, etc.).

Adversaries may gather this information in various ways, such as direct collection actions via Active Scanning or Phishing for Information. Adversaries may also compromise sites then include malicious content designed to collect host information from visitors.[1] Information about hosts may also be exposed to adversaries via online or other accessible data sets (ex: Social Media or Search Victim-Owned Websites). 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 initial access (ex: Supply Chain Compromise or External Remote Services).

Adversaries may also gather victim host information via User-Agent HTTP headers, which are sent to a server to identify the application, operating system, vendor, and/or version of the requesting user agent. This can be used to inform the adversary’s follow-on action. For example, adversaries may check user agents for the requesting operating system, then only serve malware for target operating systems while ignoring others.[2]

Adversaries may gather information about the victim's identity that can be used during targeting. Information about identities may include a variety of details, including personal data (ex: employee names, email addresses, security question responses, etc.) as well as sensitive details such as credentials or multi-factor authentication (MFA) configurations.

Adversaries may gather this information in various ways, such as direct elicitation via Phishing for Information. Information about users could also be enumerated via other active means (i.e. Active Scanning) such as probing and analyzing responses from authentication services that may reveal valid usernames in a system or permitted MFA /methods associated with those usernames.[1][2] Information about victims may also be exposed to adversaries via online or other accessible data sets (ex: Social Media or Search Victim-Owned Websites).[3][4][5][6][7][8][9][10]

Gathering this information may reveal opportunities for other forms of reconnaissance (ex: Search Open Websites/Domains or Phishing for Information), establishing operational resources (ex: Compromise Accounts), and/or initial access (ex: Phishing or Valid Accounts).

Adversaries may gather information about the victim's networks that can be used during targeting. Information about networks may include a variety of details, including administrative data (ex: IP ranges, domain names, etc.) as well as specifics regarding its topology and operations.

Adversaries may gather this information in various ways, such as direct collection actions via Active Scanning or Phishing for Information. Information about networks may also be exposed to adversaries via online or other accessible data sets (ex: Search Open Technical Databases).[1][2][3] Gathering this information may reveal opportunities for other forms of reconnaissance (ex: Active Scanning or Search Open Websites/Domains), establishing operational resources (ex: Acquire Infrastructure or Compromise Infrastructure), and/or initial access (ex: Trusted Relationship).

Adversaries may gather information about the victim's organization that can be used during targeting. Information about an organization may include a variety of details, including the names of divisions/departments, specifics of business operations, as well as the roles and responsibilities of key employees.

Adversaries may gather this information in various ways, such as direct elicitation via Phishing for Information. Information about an organization may also be exposed to adversaries via online or other accessible data sets (ex: Social Media or Search Victim-Owned Websites).[1][2] Gathering this information may reveal opportunities for other forms of reconnaissance (ex: Phishing for Information or Search Open Websites/Domains), establishing operational resources (ex: Establish Accounts or Compromise Accounts), and/or initial access (ex: Phishing or Trusted Relationship).

Adversaries may create or generate content to support targeting and operations. This content may be used to establish personas, impersonate known individuals or organizations, and support Social Engineering, fraud, or influence activities. Written materials, audio, images, video, or other media may be developed and tailored to the target and objective.[1]

Content development may occur prior to or during an operation. Adversaries may develop or generate content in-house, source it through third parties, or produce it using AI-assisted tools. Adversaries may use AI to research targets, develop pretexts, and better understand the organizations and individuals they intend to target or deceive prior to generating content (i.e., Query Public AI Services); for obtaining access to AI tools used in content generation, see Artificial Intelligence.

Content may be leveraged in support of techniques such as Phishing, Phishing for Information, Social Engineering, Financial Theft, or Establish Accounts. Generated or developed content does not include malicious code or scripts (i.e., Develop Capabilities and Artificial Intelligence).

Adversaries may gather information about the victim's host hardware that can be used during targeting. Information about hardware infrastructure 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: card/biometric readers, dedicated encryption hardware, etc.).

Adversaries may gather this information in various ways, such as direct collection actions via Active Scanning (ex: hostnames, 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 hardware infrastructure may also be exposed to adversaries via online or other accessible data sets (ex: job postings, network maps, assessment reports, resumes, or purchase invoices). 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 initial access (ex: Compromise Hardware Supply Chain or Hardware Additions).

Adversaries may gather the victim's IP addresses that can be used during targeting. Public IP addresses may be allocated to organizations by block, or a range of sequential addresses. Information about assigned IP addresses may include a variety of details, such as which IP addresses are in use. IP addresses may also enable an adversary to derive other details about a victim, such as organizational size, physical location(s), Internet service provider, and or where/how their publicly-facing infrastructure is hosted.

Adversaries may gather this information in various ways, such as direct collection actions via Active Scanning or Phishing for Information. Information about assigned IP addresses may also be exposed to adversaries via online or other accessible data sets (ex: Search Open Technical Databases).[1][2][3] Gathering this information may reveal opportunities for other forms of reconnaissance (ex: Active Scanning or Search Open Websites/Domains), establishing operational resources (ex: Acquire Infrastructure or Compromise Infrastructure), and/or initial access (ex: External Remote Services).

Adversaries may gather information about the victim's business tempo that can be used during targeting. Information about an organization’s business tempo may include a variety of details, including operational hours/days of the week. This information may also reveal times/dates of purchases and shipments of the victim’s hardware and software resources.

Adversaries may gather this information in various ways, such as direct elicitation via Phishing for Information. Information about business tempo may also be exposed to adversaries via online or other accessible data sets (ex: Social Media or Search Victim-Owned Websites).[1] Gathering this information may reveal opportunities for other forms of reconnaissance (ex: Phishing for Information or Search Open Websites/Domains), establishing operational resources (ex: Establish Accounts or Compromise Accounts), and/or initial access (ex: Supply Chain Compromise or Trusted Relationship)

Adversaries may gather information about identities and roles within the victim organization that can be used during targeting. Information about business roles may reveal a variety of targetable details, including identifiable information for key personnel as well as what data/resources they have access to.

Adversaries may gather this information in various ways, such as direct elicitation via Phishing for Information. Information about business roles may also be exposed to adversaries via online or other accessible data sets (ex: Social Media or Search Victim-Owned Websites).[1] Gathering this information may reveal opportunities for other forms of reconnaissance (ex: Phishing for Information or Search Open Websites/Domains), establishing operational resources (ex: Establish Accounts or Compromise Accounts), and/or initial access (ex: Phishing).

Adversaries may impersonate a trusted person or organization in order to persuade and trick a target into performing some action on their behalf. For example, adversaries may communicate with victims (via Phishing for Information, Phishing, or Internal Spearphishing) while impersonating a known sender such as an executive, colleague, or third-party vendor. Established trust can then be leveraged to accomplish an adversary’s ultimate goals, possibly against multiple victims. In many cases of business email compromise or email fraud campaigns, adversaries use impersonation to defraud victims -- deceiving them into sending money or divulging information that ultimately enables Financial Theft.

Adversaries will often also use social engineering techniques such as manipulative and persuasive language in email subject lines and body text such as `payment`, `request`, or `urgent` to push the victim to act quickly before malicious activity is detected. These campaigns are often specifically targeted against people who, due to job roles and/or accesses, can carry out the adversary’s goal.   Impersonation is typically preceded by reconnaissance techniques such as Gather Victim Identity Information and Gather Victim Org Information as well as acquiring infrastructure such as email domains (i.e. Domains) to substantiate their false identity.[1] There is the potential for multiple victims in campaigns involving impersonation. For example, an adversary may Compromise Accounts targeting one organization which can then be used to support impersonation against other entities.[2]

Adversaries may impersonate a trusted person or organization in order to persuade and trick a target into performing some action on their behalf. For example, adversaries may communicate with victims (via Phishing for Information, Phishing, or Internal Spearphishing) while impersonating a known sender such as an executive, colleague, or third-party vendor. Established trust can then be leveraged to accomplish an adversary’s ultimate goals, possibly against multiple victims.

In many cases of business email compromise or email fraud campaigns, adversaries use impersonation to defraud victims -- deceiving them into sending money or divulging information that ultimately enables Financial Theft.

Adversaries will often also use social engineering techniques such as manipulative and persuasive language in email subject lines and body text such as `payment`, `request`, or `urgent` to push the victim to act quickly before malicious activity is detected. These campaigns are often specifically targeted against people who, due to job roles and/or accesses, can carry out the adversary’s goal.

Impersonation is typically preceded by reconnaissance techniques such as Gather Victim Identity Information and Gather Victim Org Information as well as acquiring infrastructure such as email domains (i.e. Domains) to substantiate their false identity.[1]

There is the potential for multiple victims in campaigns involving impersonation. For example, an adversary may Compromise Accounts targeting one organization which can then be used to support impersonation against other entities.[2]

Adversaries may transfer tools or other files from an external system into a compromised environment. Tools or files may be copied from an external adversary-controlled system to the victim network through the command and control channel or through alternate protocols such as ftp. Once present, adversaries may also transfer/spread tools between victim devices within a compromised environment (i.e. Lateral Tool Transfer).

On Windows, adversaries may use various utilities to download tools, such as `copy`, `finger`, certutil, and PowerShell commands such as IEX(New-Object Net.WebClient).downloadString() and Invoke-WebRequest. On Linux and macOS systems, a variety of utilities also exist, such as `curl`, `scp`, `sftp`, `tftp`, `rsync`, `finger`, and `wget`.[1] A number of these tools, such as `wget`, `curl`, and `scp`, also exist on ESXi. After downloading a file, a threat actor may attempt to verify its integrity by checking its hash value (e.g., via `certutil -hashfile`).[2]

Adversaries may also abuse installers and package managers, such as `yum` or `winget`, to download tools to victim hosts. Adversaries have also abused file application features, such as the Windows `search-ms` protocol handler, to deliver malicious files to victims through remote file searches invoked by User Execution (typically after interacting with Phishing lures).[3]

Files can also be transferred using various Web Services as well as native or otherwise present tools on the victim system.[4] In some cases, adversaries may be able to leverage services that sync between a web-based and an on-premises client, such as Dropbox or OneDrive, to transfer files onto victim systems. For example, by compromising a cloud account and logging into the service's web portal, an adversary may be able to trigger an automatic syncing process that transfers the file onto the victim's machine.[5]

When programs are executed that need additional privileges than are present in the current user context, it is common for the operating system to prompt the user for proper credentials to authorize the elevated privileges for the task (ex: Bypass User Account Control).

Adversaries may mimic this functionality to prompt users for credentials with a seemingly legitimate prompt for a number of reasons that mimic normal usage, such as a fake installer requiring additional access or a fake malware removal suite.[1] This type of prompt can be used to collect credentials via various languages such as AppleScript[2][3] and PowerShell[2][4].

The operating system and installed applications often have legitimate needs to prompt the user for sensitive information such as account credentials, bank account information, or Personally Identifiable Information (PII). Adversaries may mimic this functionality to prompt users for sensitive information.

Compared to traditional PCs, the constrained display size of mobile devices may impair the ability to provide users with contextual information, making users more susceptible to this technique’s use.[1]

Specific approaches to this technique include:

### Impersonate the identity of a legitimate application

A malicious application could impersonate the identity of a legitimate application (e.g. use the same application name and/or icon) and get installed on the device. The malicious app could then prompt the user for sensitive information.[2]

### Display a prompt on top of a running legitimate application

A malicious application could display a prompt on top of a running legitimate application to trick users into entering sensitive information into the malicious application rather than the legitimate application. Typically, the malicious application would need to know when the targeted application (and individual activity within the targeted application) is running in the foreground, so that the malicious application knows when to display its prompt. Android 5.0 and 5.1.1, respectively, increased the difficulty of determining the current foreground application through modifications to the `ActivityManager` API.[3][4]. A malicious application can still abuse Android’s accessibility features to determine which application is currently in the foreground.[5] Approaches to display a prompt include:

* A malicious application could start a new activity on top of a running legitimate application.[1][6] Android 10 places new restrictions on the ability for an application to start a new activity on top of another application, which may make it more difficult for adversaries to utilize this technique.[7] * A malicious application could create an application overlay window on top of a running legitimate application. Applications must hold the `SYSTEM_ALERT_WINDOW` permission to create overlay windows. This permission is handled differently than typical Android permissions, and at least under certain conditions is automatically granted to applications installed from the Google Play Store.[8][9][10] The `SYSTEM_ALERT_WINDOW` permission and its associated ability to create application overlay windows are expected to be deprecated in a future release of Android in favor of a new API.[11]

### Fake device notifications

A malicious application could send fake device notifications to the user. Clicking on the device notification could trigger the malicious application to display an input prompt.[12]

An adversary could attempt to install insecure or malicious configuration settings on the mobile device, through means such as phishing emails or text messages either directly containing the configuration settings as an attachment, or containing a web link to the configuration settings. The device user may be tricked into installing the configuration settings through social engineering techniques [1].

For example, an unwanted Certification Authority (CA) certificate could be placed in the device's trusted certificate store, increasing the device's susceptibility to adversary-in-the-middle network attacks seeking to eavesdrop on or manipulate the device's network communication (Eavesdrop on Insecure Network Communication and Manipulate Device Communication).

On iOS, malicious Configuration Profiles could contain unwanted Certification Authority (CA) certificates or other insecure settings such as unwanted proxy server or VPN settings to route the device's network traffic through an adversary's system. The device could also potentially be enrolled into a malicious Mobile Device Management (MDM) system [2].

After they already have access to accounts or systems within the environment, adversaries may use internal spearphishing to gain access to additional information or compromise other users within the same organization. Internal spearphishing is multi-staged campaign where a legitimate account is initially compromised either by controlling the user's device or by compromising the account credentials of the user. Adversaries may then attempt to take advantage of the trusted internal account to increase the likelihood of tricking more victims into falling for phish attempts, often incorporating Impersonation.[1]

For example, adversaries may leverage Spearphishing Attachment or Spearphishing Link as part of internal spearphishing to deliver a payload or redirect to an external site to capture credentials through Input Capture on sites that mimic login interfaces.

Adversaries may also leverage internal chat apps, such as Microsoft Teams, to spread malicious content or engage users in attempts to capture sensitive information and/or credentials.[2]

Adversaries may abuse invisible or non-printing Unicode characters to conceal malicious content within files, scripts, or text. By inserting characters that do not visibly render, adversaries may hide data, alter how content is interpreted, or make malicious code appear as benign text or whitespace. Adversaries may encode these malicious payloads, using binary, Base64, or custom schemes, to be reconstructed at runtime through scripting features such as JavaScript Proxy traps, `eval()`, or other dynamic execution methods. This technique enables adversaries to evade visual inspection and basic static analysis by hiding malicious encoded content in innocuous text.[1][2][3]

Unicode is a standardized character encoding model that assigns a unique numerical value, known as a code point, to every character across writing systems, enabling consistent text representation across platforms, applications, and languages. Code points are represented as `U+` followed by a hexadecimal value and may be encoded using formats such as `UTF-8` or `UTF-16`. Adversaries may abuse the valid code points in Unicode that are not visibly rendered but still take up bytes, such as zero-width spaces, variation selectors, or bidirectional formatting controls, to conceal malicious payloads.[2][4][5]

Adversaries may additionally exploit Private Use Area (PUA) characters, a range of code points reserved for custom assignment. PUA characters that are not defined by a font or application are typically rendered blank.[1]

Unicode characters may also be leveraged in support of other techniques such as Phishing, Right-to-Left Override, or User Execution. For example, some adversaries may embed artificial intelligence (AI) prompt injections using invisible Unicode characters in emails or documents that appear benign when processed by AI systems.[6][7]

Adversaries may smuggle commands to download malicious payloads past content filters by hiding them within otherwise seemingly benign windows shortcut files. Windows shortcut files (.LNK) include many metadata fields, including an icon location field (also known as the `IconEnvironmentDataBlock`) designed to specify the path to an icon file that is to be displayed for the LNK file within a host directory.

Adversaries may abuse this LNK metadata to download malicious payloads. For example, adversaries have been observed using LNK files as phishing payloads to deliver malware. Once invoked (e.g., Malicious File), payloads referenced via external URLs within the LNK icon location field may be downloaded. These files may also then be invoked by Command and Scripting Interpreter/System Binary Proxy Execution arguments within the target path field of the LNK.[1][2]

LNK Icon Smuggling may also be utilized post compromise, such as malicious scripts executing an LNK on an infected host to download additional malicious payloads.

Adversaries may put in place resources that are referenced by a link that can be used during targeting. An adversary may rely upon a user clicking a malicious link in order to divulge information (including credentials) or to gain execution, as in Malicious Link. Links can be used for spearphishing, such as sending an email accompanied by social engineering text to coax the user to actively click or copy and paste a URL into a browser. Prior to a phish for information (as in Spearphishing Link) or a phish to gain initial access to a system (as in Spearphishing Link), an adversary must set up the resources for a link target for the spearphishing link.

Typically, the resources for a link target will be an HTML page that may include some client-side script such as JavaScript to decide what content to serve to the user. Adversaries may clone legitimate sites to serve as the link target, this can include cloning of login pages of legitimate web services or organization login pages in an effort to harvest credentials during Spearphishing Link.[1][2] Adversaries may also Upload Malware and have the link target point to malware for download/execution by the user.

Adversaries may purchase domains similar to legitimate domains (ex: homoglyphs, typosquatting, different top-level domain, etc.) during acquisition of infrastructure (Domains) to help facilitate Malicious Link.

Links can be written by adversaries to mask the true destination in order to deceive victims by abusing the URL schema and increasing the effectiveness of phishing.[3][4]

Adversaries may also use free or paid accounts on link shortening services and Platform-as-a-Service providers to host link targets while taking advantage of the widely trusted domains of those providers to avoid being blocked while redirecting victims to malicious pages.[5][6][7][8] In addition, adversaries may serve a variety of malicious links through uniquely generated URIs/URLs (including one-time, single use links).[9][10][11][12] Finally, adversaries may take advantage of the decentralized nature of the InterPlanetary File System (IPFS) to host link targets that are difficult to remove.[13]

Adversaries may abuse the “linked devices” feature on messaging applications, such as Signal and WhatsApp, to register the user’s account to an adversary-controlled device. By abusing the “linked devices” feature, adversaries may achieve and maintain persistence through the user’s account, may collect information, such as the user’s messages and contacts list, and may send future messages from the linked device.

Signal is a messaging application that uses the open-source Signal Protocol to encrypt messages and calls; similarly, WhatsApp is a messaging application that has end-to-end encryption and other security measures to protect messages and calls. Both applications have a “linked devices” feature that allows users to access their Signal and/or WhatsApp accounts from different devices, such as a Windows or Mac desktop, an iPad or an Android tablet.[1][2]

Adversaries may use Phishing techniques to trick the user into scanning a quick-response (QR) code, which is used to link the user’s Signal and/or WhatsApp account to an adversary-controlled device. For example, adversaries may masquerade QR codes as group invites, security alerts or as legitimate instructions for pairing linked devices. Upon scanning the QR code in Signal, users may click on the “Transfer Message History” option to sync the linked devices, which may allow adversaries to collect more information about the user. Upon scanning the QR code in WhatsApp, the user’s device will automatically send an end-to-end encrypted copy of recent message history to the adversary-controlled device.

An adversary may rely upon a user copying and pasting code in order to gain execution. Users may be subjected to social engineering to get them to copy and paste code directly into a Command and Scripting Interpreter. One such strategy is "ClickFix," in which adversaries present users with seemingly helpful solutions—such as prompts to fix errors or complete CAPTCHAs—that instead instruct the user to copy and paste malicious code.

Malicious websites, such as those used in Drive-by Compromise, may present fake error messages or CAPTCHA prompts that instruct users to open a terminal or the Windows Run Dialog box and execute an arbitrary command. These commands may be obfuscated using encoding or other techniques to conceal malicious intent. Once executed, the adversary will typically be able to establish a foothold on the victim's machine.[1][2][3][4]

Adversaries may also leverage phishing emails for this purpose. When a user attempts to open an attachment, they may be presented with a fake error and offered a malicious command to paste as a solution, consistent with the "ClickFix" strategy.[5][6]

Tricking a user into executing a command themselves may help to bypass email filtering, browser sandboxing, or other mitigations designed to protect users against malicious downloaded files.

An adversary may rely upon a user opening a malicious file in order to gain execution. Users may be subjected to social engineering to get them to open a file that will lead to code execution. This user action will typically be observed as follow-on behavior from Spearphishing Attachment. Adversaries may use several types of files that require a user to execute them, including .doc, .pdf, .xls, .rtf, .scr, .exe, .lnk, .pif, .cpl, .reg, and .iso.[1]

Adversaries may employ various forms of Masquerading and Obfuscated Files or Information to increase the likelihood that a user will open and successfully execute a malicious file. These methods may include using a familiar naming convention and/or password protecting the file and supplying instructions to a user on how to open it.[2]

While Malicious File frequently occurs shortly after Initial Access it may occur at other phases of an intrusion, such as when an adversary places a file in a shared directory or on a user's desktop hoping that a user will click on it. This activity may also be seen shortly after Internal Spearphishing.