EXPLORE DETECTIONS
Windows Cloud Files Filter Loaded by Uncommon Process
The following analytic detects cldapi.dll being loaded by a process not associated with legitimate cloud sync activity. The Windows Cloud Files API (cldapi.dll) is abused by several local privilege escalation exploits.
Windows Cloud Files Filter Log Created by Non-System Process
Detects a non-system process causing creation of CldFlt0.etl under C:\Windows\System32\LogFiles\CloudFiles\. This path is initialised by the CldFlt driver when a process calls CfRegisterSyncRoot() or CfConnectSyncRoot(). In the RedSun exploit this is a side-effect of the DoCloudStuff() function that registers a fake sync provider to create the cloud-tagged bait file. Legitimate cloud providers (OneDrive etc.) register sync roots from SYSTEM-level service processes, not from user-context executables.
Windows Cloud Sensitive File Read Access By Uncommon Process
This analytic detects uncommon processes reading or requesting read access to sensitive files from cloud providers on Windows endpoints. It monitors Windows Security Event 4663 for ReadData (AccessMask 0x1) operations against sensitive files from cloud providers such as Azure. Access by any process outside the known toolchain may indicate credential theft or cloud identity reconnaissance activity, including infostealer behavior such as one observed in Vidar Stealer variants. This detection currently only supports Azure sensitive files, but will be extended to support other cloud providers in the future.
Windows Cmdline Tool Execution From Non-Shell Process
The following analytic identifies instances where `ipconfig.exe`, `systeminfo.exe`, or similar tools are executed by a non-standard shell parent process, excluding CMD, PowerShell, or Explorer. This detection leverages Endpoint Detection and Response (EDR) telemetry to monitor process creation events. Such behavior is significant as it may indicate adversaries using injected processes to perform system discovery, a tactic observed in FIN7's JSSLoader. If confirmed malicious, this activity could allow attackers to gather critical host information, aiding in further exploitation or lateral movement within the network.
Windows Cobalt Strike PowerShell Loader
Detects the PowerShell pattern used at the end of a Cobalt Strike PowerShell loader to perform the decompression of the executable. This loader is used in attacks such as scripted web delivery. Cobalt Strike is a legitimate, commercial penetration testing tool that has been largely co-opted by ransomware gangs to launch attacks. Cobalt Strike's popularity is mainly due to its beacons or payload being stealthy, and easily customizable. Cobalt Strike Beacon provides encrypted communication with the C&C server to send information and receive commands.
Windows COM Hijacking InprocServer32 Modification
The following analytic detects the modification of the InProcServer32 registry key by reg.exe, indicative of potential COM hijacking. This detection leverages data from Endpoint Detection and Response (EDR) agents, focusing on process and command-line execution logs. COM hijacking is significant as it allows adversaries to insert malicious code that executes in place of legitimate software, providing a means for persistence. If confirmed malicious, this activity could enable attackers to execute arbitrary code, disrupt legitimate system components, and maintain long-term access to the compromised environment.
Windows Command and Scripting Interpreter Hunting Path Traversal
The following analytic identifies path traversal command-line executions, leveraging data from Endpoint Detection and Response (EDR) agents. It detects patterns in command-line arguments indicative of path traversal techniques, such as multiple instances of "/..", "\..", or "\\..". This activity is significant as it often indicates attempts to evade defenses by executing malicious code, such as through msdt.exe. If confirmed malicious, this behavior could allow attackers to execute arbitrary code, potentially leading to system compromise, data exfiltration, or further lateral movement within the network.
Windows Command and Scripting Interpreter Path Traversal Exec
The following analytic detects path traversal command-line execution, often used in malicious documents to execute code via msdt.exe for defense evasion. It leverages Endpoint Detection and Response (EDR) data, focusing on specific patterns in process paths. This activity is significant as it can indicate an attempt to bypass security controls and execute unauthorized code. If confirmed malicious, this behavior could lead to code execution, privilege escalation, or persistence within the environment, potentially allowing attackers to deploy malware or leverage other living-off-the-land binaries (LOLBins).
Windows Command Obfuscation with Environment Variable Substrings
Detects command obfuscation by using a technique to build a target command using character indexes from environment variables. This hides the true intent of the command by building it on the fly. In Windows command prompt, you can use the :~ format to extract substrings from environment variable values. This behavior has been observed in various malware families, including Cobalt Strike and Meterpreter.
Windows Command Shell DCRat ForkBomb Payload
The following analytic detects the execution of a DCRat "forkbomb" payload, which spawns multiple cmd.exe processes that launch notepad.exe instances in quick succession. This detection leverages Endpoint Detection and Response (EDR) data, focusing on the rapid creation of cmd.exe and notepad.exe processes within a 30-second window. This activity is significant as it indicates a potential DCRat infection, a known Remote Access Trojan (RAT) with destructive capabilities. If confirmed malicious, this behavior could lead to system instability, resource exhaustion, and potential disruption of services.
Windows Common Abused Cmd Shell Risk Behavior
The following analytic identifies instances where four or more distinct detection analytics are associated with malicious command line behavior on a specific host. This detection leverages the Command Line Interface (CLI) data from various sources to identify suspicious activities. This behavior is significant as it often indicates attempts to execute malicious commands, access sensitive data, install backdoors, or perform other nefarious actions. If confirmed malicious, attackers could gain unauthorized control, exfiltrate information, escalate privileges, or launch further attacks within the network, leading to severe compromise.
Windows Compatibility Telemetry Suspicious Child Process
The following analytic detects the execution of CompatTelRunner.exe with parameters indicative of a process not part of the normal "Microsoft Compatibility Appraiser" telemetry collection. It leverages data from Endpoint Detection and Response (EDR) agents, focusing on process names, parent processes, and command-line arguments. This activity is significant because CompatTelRunner.exe and the "Microsoft Compatibility Appraiser" task always run as System and can be used to elevate privileges or establish a highly privileged persistence mechanism. If confirmed malicious, this could enable unauthorized code execution, privilege escalation, or persistent access to the compromised system.
Windows Compatibility Telemetry Tampering Through Registry
This detection identifies suspicious modifications to the Windows Compatibility Telemetry registry settings, specifically within the "TelemetryController" registry key and "Command" registry value. It leverages data from the Endpoint.Registry data model, focusing on registry paths and values indicative of such changes. This activity is significant because CompatTelRunner.exe and the "Microsoft Compatibility Appraiser" task always run as System and can be used to elevate privileges or establish a highly privileged persistence mechanism. If confirmed malicious, this could enable unauthorized code execution, privilege escalation, or persistent access to the compromised system.
Windows Computer Account Changed to Domain Controller
Detects a modification to the User Account Control flags for a computer account where the `SERVER_TRUST_ACCOUNT` flag is set. This flag is normally associated with domain controller computer accounts. This activity may indicate a legitimate domain controller promotion or, if unexpected, an attempt to grant a computer account domain controller-like trust within Active Directory.
Windows Computer Account Created by Computer Account
The following analytic identifies a computer account creating a new computer account with a specific Service Principal Name (SPN) "RestrictedKrbHost". This detection leverages Windows Security Event Logs, specifically EventCode 4741, to identify such activities. This behavior is significant as it may indicate an attempt to establish unauthorized Kerberos authentication channels, potentially leading to lateral movement or privilege escalation. If confirmed malicious, this activity could allow an attacker to impersonate services, access sensitive information, or maintain persistence within the network.
Windows Computer Account Requesting Kerberos Ticket
The following analytic detects a computer account requesting a Kerberos ticket, which is unusual as typically user accounts request these tickets. This detection leverages Windows Security Event Logs, specifically EventCode 4768, to identify instances where the TargetUserName ends with a dollar sign ($), indicating a computer account. This activity is significant because it may indicate the use of tools like KrbUpRelay or other Kerberos-based attacks. If confirmed malicious, this could allow attackers to impersonate computer accounts, potentially leading to unauthorized access and lateral movement within the network.
Windows Computer Account With SPN
The following analytic detects the addition of Service Principal Names (SPNs) HOST and RestrictedKrbHost to a computer account, indicative of KrbRelayUp behavior. This detection leverages Windows Security Event Logs, specifically EventCode 4741, to identify changes in SPNs. This activity is significant as it is commonly associated with Kerberos-based attacks, which can be used to escalate privileges or perform lateral movement within a network. If confirmed malicious, this behavior could allow an attacker to impersonate services, potentially leading to unauthorized access to sensitive resources.
Windows ComputerDefaults Spawning a Process
The following analytic detects the spawning of ComputerDefaults.exe, a Windows system process used to manage default application associations. While normally legitimate, this process can be exploited by attackers to bypass User Account Control (UAC) and execute unauthorized code with elevated privileges. Detection focuses on abnormal execution patterns, unusual parent-child process relationships, or deviations from standard paths. Such behavior may indicate attempts to modify system defaults or run malicious scripts undetected. Monitoring ComputerDefaults.exe is critical to identify potential security threats, prevent privilege escalation, and maintain system integrity by distinguishing normal operations from suspicious activity.
Windows ConHost with Headless Argument
The following analytic detects the unusual invocation of the Windows Console Host process (conhost.exe) with the undocumented --headless parameter. This detection leverages Endpoint Detection and Response (EDR) telemetry, specifically monitoring for command-line executions where conhost.exe is executed with the --headless argument. This activity is significant for a SOC as it is not commonly used in legitimate operations and may indicate an attacker's attempt to execute commands stealthily. If confirmed malicious, this behavior could lead to persistence, lateral movement, or other malicious activities, potentially resulting in data exfiltration or system compromise.
Windows ConsoleHost History File Deletion
The following analytic detects the deletion of the ConsoleHost_history.txt file, which stores command history for PowerShell sessions. Attackers may attempt to remove this file to cover their tracks and evade detection during post-exploitation activities. This detection focuses on file deletion commands executed via PowerShell, Command Prompt, or scripting languages that specifically target ConsoleHost_history.txt, typically located at %APPDATA%\Microsoft\Windows\PowerShell\PSReadline\ConsoleHost_history.txt. Identifying such activity can help uncover potential anti-forensic behavior and suspicious administrative actions.
Windows ConvertTo-AADIntBackdoor Execution Via PowerShell Script
This analytic detects the execution of the ConvertTo-AADIntBackdoor command via PowerShell Script Block Logging. The ConvertTo-AADIntBackdoor command is part of the AADInternals toolkit, which is used primarily for security testing and administrative tasks in Azure Active Directory (Azure AD) environments. This particular command is designed to create a "backdoor" in a federated Azure AD domain. When executed, ConvertTo-AADIntBackdoor modifies the federation settings of a domain by adding or changing the federation configuration to allow an attacker to control the authentication process. This manipulation enables the creation of security tokens that can impersonate any user within the Azure AD tenant. Consequently, this allows an attacker to bypass Multi-Factor Authentication (MFA), escalate privileges, and maintain persistent access to the Azure AD environment.
Windows Create Local Account
The following analytic detects the creation of a new local user account on a Windows system. It leverages Windows Security Audit logs, specifically event ID 4720, to identify this activity. Monitoring the creation of local accounts is crucial for a SOC as it can indicate unauthorized access or lateral movement within the network. If confirmed malicious, this activity could allow an attacker to establish persistence, escalate privileges, or gain unauthorized access to sensitive systems and data.
Windows Create Local Administrator Account Via Net
The following analytic detects the creation of a local administrator account using the "net.exe" command. It leverages Endpoint Detection and Response (EDR) data to identify processes named "net.exe" with the "/add" parameter and keywords related to administrator accounts. This activity is significant as it may indicate an attacker attempting to gain persistent access or escalate privileges. If confirmed malicious, this could lead to unauthorized access, data theft, or further system compromise. Review the process details, user context, and related artifacts to determine the legitimacy of the activity.
Windows Credential Access From Browser Password Store
The following analytic identifies a possible non-common browser process accessing its browser user data profile. This tactic/technique has been observed in various Trojan Stealers, such as SnakeKeylogger, which attempt to gather sensitive browser information and credentials as part of their exfiltration strategy. Detecting this anomaly can serve as a valuable pivot for identifying processes that access lists of browser user data profiles unexpectedly. This detection uses a lookup file `browser_app_list` that maintains a list of well known browser applications and the browser paths that are allowed to access the browser user data profiles.