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 acquire credentials from web browsers by reading files specific to the target browser.[[Talos Olympic Destroyer 2018](https://app.tidalcyber.com/references/25a2e179-7abd-4091-8af4-e9d2bf24ef11)] Web browsers commonly save credentials such as website usernames and passwords so that they do not need to be entered manually in the future. Web browsers typically store the credentials in an encrypted format within a credential store; however, methods exist to extract plaintext credentials from web browsers.For example, on Windows systems, encrypted credentials may be obtained from Google Chrome by reading a database file, AppData\Local\Google\Chrome\User Data\Default\Login Data and executing a SQL query: SELECT action_url, username_value, password_value FROM logins;. The plaintext password can then be obtained by passing the encrypted credentials to the Windows API function CryptUnprotectData, which uses the victim’s cached logon credentials as the decryption key.[[Microsoft CryptUnprotectData April 2018](https://app.tidalcyber.com/references/258088ae-96c2-4520-8eb5-1a7e540a9a24)]Adversaries have executed similar procedures for common web browsers such as FireFox, Safari, Edge, etc.[[Proofpoint Vega Credential Stealer May 2018](https://app.tidalcyber.com/references/c52fe62f-4df4-43b0-a126-2df07dc61fc0)][[FireEye HawkEye Malware July 2017](https://app.tidalcyber.com/references/7ad228a8-5450-45ec-86fc-ea038f7c6ef7)] Windows stores Internet Explorer and Microsoft Edge credentials in Credential Lockers managed by the [Windows Credential Manager](https://app.tidalcyber.com/technique/9503955c-fa53-452a-b717-7e23bfb4df83).
Adversaries may also acquire credentials by searching web browser process memory for patterns that commonly match credentials.[[GitHub Mimikittenz July 2016](https://app.tidalcyber.com/references/2e0a95b2-3f9a-4638-9bc5-ff1f3ac2af4b)]
After acquiring credentials from web browsers, adversaries may attempt to recycle the credentials across different systems and/or accounts in order to expand access. This can result in significantly furthering an adversary’s objective in cases where credentials gained from web browsers overlap with privileged accounts (e.g. domain administrator).
Adversaries may use [Obfuscated Files or Information](https://app.tidalcyber.com/technique/046cc07e-8700-4536-9c5b-6ecb384f52b0) to hide artifacts of an intrusion from analysis. They may require separate mechanisms to decode or deobfuscate that information depending on how they intend to use it. Methods for doing that include built-in functionality of malware or by using utilities present on the system.One such example is the use of [certutil](https://app.tidalcyber.com/software/2fe21578-ee31-4ee8-b6ab-b5f76f97d043) to decode a remote access tool portable executable file that has been hidden inside a certificate file.[[Malwarebytes Targeted Attack against Saudi Arabia](https://app.tidalcyber.com/references/735647f9-9cd4-4a20-8812-4671a3358e46)] Another example is using the Windows copy /b command to reassemble binary fragments into a malicious payload.[[Carbon Black Obfuscation Sept 2016](https://app.tidalcyber.com/references/bed8ae68-9738-46fb-abc9-0004fa35636a)]Sometimes a user’s action may be required to open it for deobfuscation or decryption as part of [User Execution](https://app.tidalcyber.com/technique/b84435ab-2ff4-4b6f-ba71-b4b815474872). The user may also be required to input a password to open a password protected compressed/encrypted file that was provided by the adversary. [[Volexity PowerDuke November 2016](https://app.tidalcyber.com/references/4026c055-6020-41bb-a4c8-54b308867023)]
Adversaries may steal data by exfiltrating it over an existing command and control channel. Stolen data is encoded into the normal communications channel using the same protocol as command and control communications.
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 attempt to take screen captures of the desktop to gather information over the course of an operation. Screen capturing functionality may be included as a feature of a remote access tool used in post-compromise operations. Taking a screenshot is also typically possible through native utilities or API calls, such as CopyFromScreen, xwd, or screencapture.[[CopyFromScreen .NET](https://app.tidalcyber.com/references/b9733af4-ffb4-416e-884e-d51649aecbce)][[Antiquated Mac Malware](https://app.tidalcyber.com/references/165edb01-2681-45a3-b76b-4eb7dee5dab9)]
Adversaries may attempt to get a listing of software and software versions that are installed on a system or in a cloud environment. Adversaries may use the information from [Software Discovery](https://app.tidalcyber.com/technique/e9bff6ff-3142-4910-8f67-19b868912602) during automated discovery to shape follow-on behaviors, including whether or not the adversary fully infects the target and/or attempts specific actions.Adversaries may attempt to enumerate software for a variety of reasons, such as figuring out what security measures are present or if the compromised system has a version of software that is vulnerable to [Exploitation for Privilege Escalation](https://app.tidalcyber.com/technique/9cc715d7-9969-485f-87a2-c9f7ed3cc44c).
Adversaries can steal application access tokens as a means of acquiring credentials to access remote systems and resources.Application access tokens are used to make authorized API requests on behalf of a user or service and are commonly used as a way to access resources in cloud and container-based applications and software-as-a-service (SaaS).[[Auth0 – Why You Should Always Use Access Tokens to Secure APIs Sept 2019](https://app.tidalcyber.com/references/8ec52402-7e54-463d-8906-f373e5855018)] OAuth is one commonly implemented framework that issues tokens to users for access to systems. Adversaries who steal account API tokens in cloud and containerized environments may be able to access data and perform actions with the permissions of these accounts, which can lead to privilege escalation and further compromise of the environment.In Kubernetes environments, processes running inside a container communicate with the Kubernetes API server using service account tokens. If a container is compromised, an attacker may be able to steal the container’s token and thereby gain access to Kubernetes API commands.[[Kubernetes Service Accounts](https://app.tidalcyber.com/references/a74ffa28-8a2e-4bfd-bc66-969b463bebd9)]
Token theft can also occur through social engineering, in which case user action may be required to grant access. An application desiring access to cloud-based services or protected APIs can gain entry using OAuth 2.0 through a variety of authorization protocols. An example commonly-used sequence is Microsoft’s Authorization Code Grant flow.[[Microsoft Identity Platform Protocols May 2019](https://app.tidalcyber.com/references/a99d2292-be39-4e55-a952-30c9d6a3d0a3)][[Microsoft – OAuth Code Authorization flow – June 2019](https://app.tidalcyber.com/references/a41c2123-8b8d-4f98-a535-e58e3e746b69)] An OAuth access token enables a third-party application to interact with resources containing user data in the ways requested by the application without obtaining user credentials.
Adversaries can leverage OAuth authorization by constructing a malicious application designed to be granted access to resources with the target user’s OAuth token.[[Amnesty OAuth Phishing Attacks, August 2019](https://app.tidalcyber.com/references/0b0f9cf6-f0af-4f86-9699-a63ff36c49e2)][[Trend Micro Pawn Storm OAuth 2017](https://app.tidalcyber.com/references/7d12c764-facd-4086-acd0-5c0287344520)] The adversary will need to complete registration of their application with the authorization server, for example Microsoft Identity Platform using Azure Portal, the Visual Studio IDE, the command-line interface, PowerShell, or REST API calls.[[Microsoft – Azure AD App Registration – May 2019](https://app.tidalcyber.com/references/36a06c99-55ca-4163-9450-c3b84ae10039)] Then, they can send a [Spearphishing Link](https://app.tidalcyber.com/technique/d08a9977-9fc2-46bb-84f9-dbb5187c426d) to the target user to entice them to grant access to the application. Once the OAuth access token is granted, the application can gain potentially long-term access to features of the user account through [Application Access Token](https://app.tidalcyber.com/technique/8592f37d-850a-43d1-86f2-cc981ad7d7dc).[[Microsoft – Azure AD Identity Tokens – Aug 2019](https://app.tidalcyber.com/references/44767d53-8cd7-44dd-a69d-8a7bebc1d87d)]
Application access tokens may function within a limited lifetime, limiting how long an adversary can utilize the stolen token. However, in some cases, adversaries can also steal application refresh tokens[[Auth0 Understanding Refresh Tokens](https://app.tidalcyber.com/references/84eb3d8a-f6b1-4bb5-9411-2c8da29b5946)], allowing them to obtain new access tokens without prompting the user.
An adversary may steal web application or service session cookies and use them to gain access to web applications or Internet services as an authenticated user without needing credentials. Web applications and services often use session cookies as an authentication token after a user has authenticated to a website.Cookies are often valid for an extended period of time, even if the web application is not actively used. Cookies can be found on disk, in the process memory of the browser, and in network traffic to remote systems. Additionally, other applications on the targets machine might store sensitive authentication cookies in memory (e.g. apps which authenticate to cloud services). Session cookies can be used to bypasses some multi-factor authentication protocols.[[Pass The Cookie](https://app.tidalcyber.com/references/dc67930f-5c7b-41be-97e9-d8f4a55e6019)]There are several examples of malware targeting cookies from web browsers on the local system.[[Kaspersky TajMahal April 2019](https://app.tidalcyber.com/references/1ed20522-52ae-4d0c-b42e-c680490958ac)][[Unit 42 Mac Crypto Cookies January 2019](https://app.tidalcyber.com/references/0a88e730-8ed2-4983-8f11-2cb2e4abfe3e)] There are also open source frameworks such as Evilginx 2 and Muraena that can gather session cookies through a malicious proxy (ex: [Adversary-in-the-Middle](https://app.tidalcyber.com/technique/d98dbf30-c454-42ff-a9f3-2cd3319cc0d9)) that can be set up by an adversary and used in phishing campaigns.[[Github evilginx2](https://app.tidalcyber.com/references/322e5d90-5095-47ea-b0e2-e7e5fb45fcca)][[GitHub Mauraena](https://app.tidalcyber.com/references/578ecf62-b546-4f52-9d50-92557edf2dd4)]
After an adversary acquires a valid cookie, they can then perform a [Web Session Cookie](https://app.tidalcyber.com/technique/d36a5323-e249-44e8-9c8b-5cc9c023a5e1) technique to login to the corresponding web application.
Adversaries may try to gather information about registered local system services. Adversaries may obtain information about services using tools as well as OS utility commands such as sc query, tasklist /svc, systemctl --type=service, and net start.Adversaries may use the information from [System Service Discovery](https://app.tidalcyber.com/technique/e0a347e2-2ac5-458b-ab0f-18d81b6d6055) during automated discovery to shape follow-on behaviors, including whether or not the adversary fully infects the target and/or attempts specific actions.
An adversary may gather the system time and/or time zone from a local or remote system. The system time is set and stored by the Windows Time Service within a domain to maintain time synchronization between systems and services in an enterprise network. [[MSDN System Time](https://app.tidalcyber.com/references/5e15e03b-be8b-4f3d-a3ae-0df7a4ecfbec)][[Technet Windows Time Service](https://app.tidalcyber.com/references/0d908e07-abc1-40fc-b147-9b9fd483b262)]System time information may be gathered in a number of ways, such as with [Net](https://app.tidalcyber.com/software/c9b8522f-126d-40ff-b44e-1f46098bd8cc) on Windows by performing net time \\hostname to gather the system time on a remote system. The victim’s time zone may also be inferred from the current system time or gathered by using w32tm /tz.[[Technet Windows Time Service](https://app.tidalcyber.com/references/0d908e07-abc1-40fc-b147-9b9fd483b262)]On network devices, [Network Device CLI](https://app.tidalcyber.com/technique/284bfbb3-99f0-4c3d-bc1f-ab74065b7907) commands such as `show clock detail` can be used to see the current time configuration.[[show_clock_detail_cisco_cmd](https://app.tidalcyber.com/references/a2215813-31b0-5624-92d8-479e7bd1a30b)]
This information could be useful for performing other techniques, such as executing a file with a [Scheduled Task/Job](https://app.tidalcyber.com/technique/0baf02af-ffaa-403f-9f0d-da51f463a1d8)[[RSA EU12 They’re Inside](https://app.tidalcyber.com/references/8330ab88-9c73-4332-97d6-c1fb95b1a155)], or to discover locality information based on time zone to assist in victim targeting (i.e. [System Location Discovery](https://app.tidalcyber.com/technique/90e6a093-3e87-4d74-8b68-38c7d7e5e93c)). Adversaries may also use knowledge of system time as part of a time bomb, or delaying execution until a specified date/time.[[AnyRun TimeBomb](https://app.tidalcyber.com/references/cd369bf9-80a8-426f-a0aa-c9745b40696c)]
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)]
