Description: Formbook is an information-stealing malware, discovered in 2016, that is capable of stealing data entered into HTML website forms and logging keystrokes (https://www.blackberry.com/us/en/solutions/endpoint-security/ransomware-protection/formbook) and also acting as a downloader for other malware (https://www.checkpoint.com/cyber-hub/threat-prevention/what-is-malware/what-is-formbook-malware/). xLoader is a JavaScript-based, cross-platform Formbook variant discovered in 2020 that is crafted to infect macOS as well as Windows systems. Check Point Research’s 2022 Mid-Year Report released in August 2022 placed Formbook as the “most prevalent” infostealer malware globally (and second-most prevalent of all malware types globally, behind only Emotet): https://www.checkpoint.com/downloads/resources/cyber-attack-trends-report-mid-year-2022.pdf.
Adversaries may communicate using OSI application layer protocols to avoid detection/network filtering by blending in with existing traffic. Commands to the remote system, and often the results of those commands, will be embedded within the protocol traffic between the client and server.Adversaries may utilize many different protocols, including those used for web browsing, transferring files, electronic mail, or DNS. For connections that occur internally within an enclave (such as those between a proxy or pivot node and other nodes), commonly used protocols are SMB, SSH, or RDP.
Adversaries may configure system settings to automatically execute a program during system boot or logon to maintain persistence or gain higher-level privileges on compromised systems. Operating systems may have mechanisms for automatically running a program on system boot or account logon.[[Microsoft Run Key](https://app.tidalcyber.com/references/0d633a50-4afd-4479-898e-1a785f5637da)][[MSDN Authentication Packages](https://app.tidalcyber.com/references/e9bb8434-9b6d-4301-bfe2-5c83ceabb020)][[Microsoft TimeProvider](https://app.tidalcyber.com/references/cf7c1db8-6282-4ccd-9609-5a012faf70d6)][[Cylance Reg Persistence Sept 2013](https://app.tidalcyber.com/references/9e9c745f-19fd-4218-b8dc-85df804ecb70)][[Linux Kernel Programming](https://app.tidalcyber.com/references/70f31f19-e0b3-40b1-b8dd-6667557bb334)] These mechanisms may include automatically executing programs that are placed in specially designated directories or are referenced by repositories that store configuration information, such as the Windows Registry. An adversary may achieve the same goal by modifying or extending features of the kernel.Since some boot or logon autostart programs run with higher privileges, an adversary may leverage these to elevate privileges.
Adversaries may collect data stored in the clipboard from users copying information within or between applications.For example, on Windows adversaries can access clipboard data by using clip.exe or Get-Clipboard.[[MSDN Clipboard](https://app.tidalcyber.com/references/2c1b2d58-a5dc-4aee-8bdb-129a81c10408)][[clip_win_server](https://app.tidalcyber.com/references/8a961fa1-def0-5efe-8599-62e884d4ea22)][[CISA_AA21_200B](https://app.tidalcyber.com/references/633c6045-8990-58ae-85f0-00139aa9a091)] Additionally, adversaries may monitor then replace users’ clipboard with their data (e.g., [Transmitted Data Manipulation](https://app.tidalcyber.com/technique/70365fab-8531-4a0e-b147-7cabdfdef243)).[[mining_ruby_reversinglabs](https://app.tidalcyber.com/references/ca2074d8-330b-544e-806f-ddee7b702631)]
macOS and Linux also have commands, such as pbpaste, to grab clipboard contents.[[Operating with EmPyre](https://app.tidalcyber.com/references/459a4ad5-0e28-4bfc-a73e-b9dd516d516f)]
Adversaries may search for common password storage locations to obtain user credentials. Passwords are stored in several places on a system, depending on the operating system or application holding the credentials. There are also specific applications that store passwords to make it easier for users manage and maintain. Once credentials are obtained, they can be used to perform lateral movement and access restricted information.
Adversaries may collect data related to managed devices from configuration repositories. Configuration repositories are used by management systems in order to configure, manage, and control data on remote systems. Configuration repositories may also facilitate remote access and administration of devices.Adversaries may target these repositories in order to collect large quantities of sensitive system administration data. Data from configuration repositories may be exposed by various protocols and software and can store a wide variety of data, much of which may align with adversary Discovery objectives.[[US-CERT-TA18-106A](https://app.tidalcyber.com/references/1fe55557-94af-4697-a675-884701f70f2a)][[US-CERT TA17-156A SNMP Abuse 2017](https://app.tidalcyber.com/references/82b814f3-2853-48a9-93ff-701d16d97535)]
Adversaries may exploit software vulnerabilities in client applications to execute code. Vulnerabilities can exist in software due to unsecure coding practices that can lead to unanticipated behavior. Adversaries can take advantage of certain vulnerabilities through targeted exploitation for the purpose of arbitrary code execution. Oftentimes the most valuable exploits to an offensive toolkit are those that can be used to obtain code execution on a remote system because they can be used to gain access to that system. Users will expect to see files related to the applications they commonly used to do work, so they are a useful target for exploit research and development because of their high utility.Several types exist:
### Browser-based Exploitation
Web browsers are a common target through [Drive-by Compromise](https://app.tidalcyber.com/technique/d4e46fe1-cc6d-4ef0-af72-a4e8dcd71381) and [Spearphishing Link](https://app.tidalcyber.com/technique/d08a9977-9fc2-46bb-84f9-dbb5187c426d). Endpoint systems may be compromised through normal web browsing or from certain users being targeted by links in spearphishing emails to adversary controlled sites used to exploit the web browser. These often do not require an action by the user for the exploit to be executed.
### Office Applications
Common office and productivity applications such as Microsoft Office are also targeted through [Phishing](https://app.tidalcyber.com/technique/d4a36624-50cb-43d3-95af-a2e10878a533). Malicious files will be transmitted directly as attachments or through links to download them. These require the user to open the document or file for the exploit to run.
### Common Third-party Applications
Other applications that are commonly seen or are part of the software deployed in a target network may also be used for exploitation. Applications such as Adobe Reader and Flash, which are common in enterprise environments, have been routinely targeted by adversaries attempting to gain access to systems. Depending on the software and nature of the vulnerability, some may be exploited in the browser or require the user to open a file. For instance, some Flash exploits have been delivered as objects within Microsoft Office documents.
Adversaries may attempt to manipulate features of their artifacts to make them appear legitimate or benign to users and/or security tools. Masquerading occurs when the name or location of an object, legitimate or malicious, is manipulated or abused for the sake of evading defenses and observation. This may include manipulating file metadata, tricking users into misidentifying the file type, and giving legitimate task or service names.Renaming abusable system utilities to evade security monitoring is also a form of [Masquerading](https://app.tidalcyber.com/technique/a0adacc1-8d2a-4e0b-92c1-3766264df4fd).[[LOLBAS Main Site](https://app.tidalcyber.com/references/615f6fa5-3059-49fc-9fa4-5ca0aeff4331)]
Adversaries may send phishing messages to gain access to victim systems. All forms of phishing are electronically delivered social engineering. Phishing can be targeted, known as spearphishing. In spearphishing, a specific individual, company, or industry will be targeted by the adversary. More generally, adversaries can conduct non-targeted phishing, such as in mass malware spam campaigns.Adversaries may send victims emails containing malicious attachments or links, typically to execute malicious code on victim systems. Phishing may also be conducted via third-party services, like social media platforms. Phishing may also involve social engineering techniques, such as posing as a trusted source, as well as evasive techniques such as removing or manipulating emails or metadata/headers from compromised accounts being abused to send messages (e.g., [Email Hiding Rules](https://app.tidalcyber.com/technique/01505d46-8675-408d-881e-68f4d8743d47)).[[Microsoft OAuth Spam 2022](https://app.tidalcyber.com/references/086c06a0-3960-5fa8-b034-cef37a3aee90)][[Palo Alto Unit 42 VBA Infostealer 2014](https://app.tidalcyber.com/references/c3eccab6-b12b-513a-9a04-396f7b3dcf63)] Another way to accomplish this is by forging or spoofing[[Proofpoint-spoof](https://app.tidalcyber.com/references/fe9f7542-bbf0-5e34-b3a9-8596cc5aa754)] the identity of the sender which can be used to fool both the human recipient as well as automated security tools.[[cyberproof-double-bounce](https://app.tidalcyber.com/references/4406d688-c392-5244-b438-6995f38dfc61)]
Victims may also receive phishing messages that instruct them to call a phone number where they are directed to visit a malicious URL, download malware,[[sygnia Luna Month](https://app.tidalcyber.com/references/3e1c2a64-8446-538d-a148-2de87991955a)][[CISA Remote Monitoring and Management Software](https://app.tidalcyber.com/references/1ee55a8c-9e9d-520a-a3d3-1d2da57e0265)] or install adversary-accessible remote management tools onto their computer (i.e., [User Execution](https://app.tidalcyber.com/technique/b84435ab-2ff4-4b6f-ba71-b4b815474872)).[[Unit42 Luna Moth](https://app.tidalcyber.com/references/ec52bcc9-6a56-5b94-8534-23c8e7ce740f)]
Adversaries may inject malicious code into suspended and hollowed processes in order to evade process-based defenses. Process hollowing is a method of executing arbitrary code in the address space of a separate live process.Process hollowing is commonly performed by creating a process in a suspended state then unmapping/hollowing its memory, which can then be replaced with malicious code. A victim process can be created with native Windows API calls such as CreateProcess, which includes a flag to suspend the processes primary thread. At this point the process can be unmapped using APIs calls such as ZwUnmapViewOfSection or NtUnmapViewOfSection before being written to, realigned to the injected code, and resumed via VirtualAllocEx, WriteProcessMemory, SetThreadContext, then ResumeThread respectively.[[Leitch Hollowing](https://app.tidalcyber.com/references/8feb180a-bfad-42cb-b8ee-792c5088567a)][[Elastic Process Injection July 2017](https://app.tidalcyber.com/references/02c9100d-27eb-4f2f-b302-adf890055546)]
This is very similar to [Thread Local Storage](https://app.tidalcyber.com/technique/24e0b530-cca7-4c5c-83b2-97b83c716e42) but creates a new process rather than targeting an existing process. This behavior will likely not result in elevated privileges since the injected process was spawned from (and thus inherits the security context) of the injecting process. However, execution via process hollowing may also evade detection from security products since the execution is masked under a legitimate process.
Adversaries may use [Valid Accounts](https://app.tidalcyber.com/technique/a9b7eb2f-63e7-41bc-9d77-f7c4cede5406) 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).[[SSH Secure Shell](https://app.tidalcyber.com/references/ac5fc103-1946-488b-8af5-eda0636cbdd0)][[TechNet Remote Desktop Services](https://app.tidalcyber.com/references/b8fc1bdf-f602-4a9b-a51c-fa49e70f24cd)] They could also login to accessible SaaS or IaaS services, such as those that federate their identities to the domain.
Legitimate applications (such as [Software Deployment Tools](https://app.tidalcyber.com/technique/1bcf9fb5-6848-44d9-b394-ffbd3c357058) and other administrative programs) may utilize [Remote Services](https://app.tidalcyber.com/technique/30ef3f13-5e9b-4712-9adf-f0da4ef157a1) 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](https://app.tidalcyber.com/technique/af7afc1e-3374-4d1c-917b-c47c305274f5) to send the screen and control buffers and [SSH](https://app.tidalcyber.com/technique/7620ba3a-7877-4f87-90e3-588163ac0474) for secure file transfer.[[Remote Management MDM macOS](https://app.tidalcyber.com/references/e5f59848-7014-487d-9bae-bed81af1b72b)][[Kickstart Apple Remote Desktop commands](https://app.tidalcyber.com/references/f26542dd-aa61-4d2a-a05a-8f9674b49f82)][[Apple Remote Desktop Admin Guide 3.3](https://app.tidalcyber.com/references/c57c2bba-a398-4e68-b2a7-fddcf0740b61)] 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.[[FireEye 2019 Apple Remote Desktop](https://app.tidalcyber.com/references/bbc72952-988e-4c3c-ab5e-75b64e9e33f5)][[Lockboxx ARD 2019](https://app.tidalcyber.com/references/159f8495-5354-4b93-84cb-a25e56fcff3e)][[Kickstart Apple Remote Desktop commands](https://app.tidalcyber.com/references/f26542dd-aa61-4d2a-a05a-8f9674b49f82)]
Adversaries may abuse task scheduling functionality to facilitate initial or recurring execution of malicious code. Utilities exist within all major operating systems to schedule programs or scripts to be executed at a specified date and time. A task can also be scheduled on a remote system, provided the proper authentication is met (ex: RPC and file and printer sharing in Windows environments). Scheduling a task on a remote system typically may require being a member of an admin or otherwise privileged group on the remote system.[[TechNet Task Scheduler Security](https://app.tidalcyber.com/references/3a6d08ba-d79d-46f7-917d-075a98c59228)]Adversaries may use task scheduling to execute programs at system startup or on a scheduled basis for persistence. These mechanisms can also be abused to run a process under the context of a specified account (such as one with elevated permissions/privileges). Similar to [System Binary Proxy Execution](https://app.tidalcyber.com/technique/4060ad55-7ff1-4127-acad-808b2bc77655), adversaries have also abused task scheduling to potentially mask one-time execution under a trusted system process.[[ProofPoint Serpent](https://app.tidalcyber.com/references/c2f7958b-f521-4133-9aeb-c5c8fae23e78)]
Adversaries may employ various system checks to detect and avoid virtualization and analysis environments. This may include changing behaviors based on the results of checks for the presence of artifacts indicative of a virtual machine environment (VME) or sandbox. If the adversary detects a VME, they may alter their malware to disengage from the victim or conceal the core functions of the implant. They may also search for VME artifacts before dropping secondary or additional payloads. Adversaries may use the information learned from [Virtualization/Sandbox Evasion](https://app.tidalcyber.com/technique/63baf71d-f46f-4ac8-a3a6-8345ddd2f7a8) during automated discovery to shape follow-on behaviors.[[Deloitte Environment Awareness](https://app.tidalcyber.com/references/af842a1f-8f39-4b4f-b4d2-0bbb810e6c31)]Specific checks will vary based on the target and/or adversary, but may involve behaviors such as [Windows Management Instrumentation](https://app.tidalcyber.com/technique/c37795d9-8970-461f-9491-3086d6b4b69a), [PowerShell](https://app.tidalcyber.com/technique/6ca7838a-e8ad-43e8-9da6-15b640d1cbde), [System Information Discovery](https://app.tidalcyber.com/technique/a2961a00-450e-45a5-b293-f699d9f3b4ea), and [Query Registry](https://app.tidalcyber.com/technique/58722f84-b119-45a8-8e29-0065688015ee) to obtain system information and search for VME artifacts. Adversaries may search for VME artifacts in memory, processes, file system, hardware, and/or the Registry. Adversaries may use scripting to automate these checks into one script and then have the program exit if it determines the system to be a virtual environment.
Checks could include generic system properties such as host/domain name and samples of network traffic. Adversaries may also check the network adapters addresses, CPU core count, and available memory/drive size.
Other common checks may enumerate services running that are unique to these applications, installed programs on the system, manufacturer/product fields for strings relating to virtual machine applications, and VME-specific hardware/processor instructions.[[McAfee Virtual Jan 2017](https://app.tidalcyber.com/references/a541a027-733c-438f-a723-6f7e8e6f354c)] In applications like VMWare, adversaries can also use a special I/O port to send commands and receive output.
Hardware checks, such as the presence of the fan, temperature, and audio devices, could also be used to gather evidence that can be indicative a virtual environment. Adversaries may also query for specific readings from these devices.[[Unit 42 OilRig Sept 2018](https://app.tidalcyber.com/references/84815940-b98a-4f5c-82fe-7d8bf2f51a09)]
Adversaries may search compromised systems to find and obtain insecurely stored credentials. These credentials can be stored and/or misplaced in many locations on a system, including plaintext files (e.g. [Bash History](https://app.tidalcyber.com/technique/065d1cca-8ca5-4f8b-a333-2340706f589e)), operating system or application-specific repositories (e.g. [Credentials in Registry](https://app.tidalcyber.com/technique/cdac2469-52ca-42a8-aefe-0321a7e3d658)), or other specialized files/artifacts (e.g. [Private Keys](https://app.tidalcyber.com/technique/e493bf4a-0eba-4e60-a7a6-c699084dc98a)).
An adversary may rely upon specific actions by a user in order to gain execution. Users may be subjected to social engineering to get them to execute malicious code by, for example, opening a malicious document file or link. These user actions will typically be observed as follow-on behavior from forms of [Phishing](https://app.tidalcyber.com/technique/d4a36624-50cb-43d3-95af-a2e10878a533).While [User Execution](https://app.tidalcyber.com/technique/b84435ab-2ff4-4b6f-ba71-b4b815474872) 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](https://app.tidalcyber.com/technique/4f4ea659-7653-4bfd-a525-b2af32c5899b).
Adversaries may also deceive users into performing actions such as enabling [Remote Access Software](https://app.tidalcyber.com/technique/acf828f4-7e7e-43e1-bf15-ceab42021430), allowing direct control of the system to the adversary, or downloading and executing malware for [User Execution](https://app.tidalcyber.com/technique/b84435ab-2ff4-4b6f-ba71-b4b815474872). For example, tech support scams can be facilitated through [Phishing](https://app.tidalcyber.com/technique/d4a36624-50cb-43d3-95af-a2e10878a533), vishing, or various forms of user interaction. Adversaries can use a combination of these methods, such as spoofing and promoting toll-free numbers or call centers that are used to direct victims to malicious websites, to deliver and execute payloads containing malware or [Remote Access Software](https://app.tidalcyber.com/technique/acf828f4-7e7e-43e1-bf15-ceab42021430).[[Telephone Attack Delivery](https://app.tidalcyber.com/references/9670da7b-0600-4072-9ecc-65a918b89ac5)]
Adversaries may employ various means to detect and avoid virtualization and analysis environments. This may include changing behaviors based on the results of checks for the presence of artifacts indicative of a virtual machine environment (VME) or sandbox. If the adversary detects a VME, they may alter their malware to disengage from the victim or conceal the core functions of the implant. They may also search for VME artifacts before dropping secondary or additional payloads. Adversaries may use the information learned from [Virtualization/Sandbox Evasion](https://app.tidalcyber.com/technique/63baf71d-f46f-4ac8-a3a6-8345ddd2f7a8) during automated discovery to shape follow-on behaviors.[[Deloitte Environment Awareness](https://app.tidalcyber.com/references/af842a1f-8f39-4b4f-b4d2-0bbb810e6c31)]Adversaries may use several methods to accomplish [Virtualization/Sandbox Evasion](https://app.tidalcyber.com/technique/63baf71d-f46f-4ac8-a3a6-8345ddd2f7a8) such as checking for security monitoring tools (e.g., Sysinternals, Wireshark, etc.) or other system artifacts associated with analysis or virtualization. Adversaries may also check for legitimate user activity to help determine if it is in an analysis environment. Additional methods include use of sleep timers or loops within malware code to avoid operating within a temporary sandbox.[[Unit 42 Pirpi July 2015](https://app.tidalcyber.com/references/42d35b93-2866-46d8-b8ff-675df05db9db)]
