Update v8.13.20

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This section lists all updates associated with version 8.13.20 of the Fleet integration Prebuilt Security Detection Rules.

Rule Description Status Version

Untrusted DLL Loaded by Azure AD Sync Service

Identifies the load of a DLL without a valid code signature by the Azure AD Sync process, which may indicate an attempt to persist or collect sensitive credentials passing through the Azure AD synchronization server.

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Active Directory Forced Authentication from Linux Host - SMB Named Pipes

Identifies a potential forced authentication using related SMB named pipes. Attackers may attempt to force targets to authenticate to a host controlled by them to capture hashes or enable relay attacks.

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Potential File Transfer via Certreq

Identifies Certreq making an HTTP Post request. Adversaries could abuse Certreq to download files or upload data to a remote URL.

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109

Potential DNS Tunneling via NsLookup

This rule identifies a large number (15) of nslookup.exe executions with an explicit query type from the same host. This may indicate command and control activity utilizing the DNS protocol.

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211

Potential File Download via a Headless Browser

Identifies the use of a browser to download a file from a remote URL and from a suspicious parent process. Adversaries may use browsers to avoid ingress tool transfer restrictions.

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102

Outlook Home Page Registry Modification

Identifies modifications in registry keys associated with abuse of the Outlook Home Page functionality for command and control or persistence.

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101

Port Forwarding Rule Addition

Identifies the creation of a new port forwarding rule. An adversary may abuse this technique to bypass network segmentation restrictions.

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313

Remote File Download via Desktopimgdownldr Utility

Identifies the desktopimgdownldr utility being used to download a remote file. An adversary may use desktopimgdownldr to download arbitrary files as an alternative to certutil.

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213

Remote File Download via MpCmdRun

Identifies the Windows Defender configuration utility (MpCmdRun.exe) being used to download a remote file.

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213

Remote File Copy via TeamViewer

Identifies an executable or script file remotely downloaded via a TeamViewer transfer session.

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212

Potential Credential Access via Windows Utilities

Identifies the execution of known Windows utilities often abused to dump LSASS memory or the Active Directory database (NTDS.dit) in preparation for credential access.

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214

NTDS or SAM Database File Copied

Identifies a copy operation of the Active Directory Domain Database (ntds.dit) or Security Account Manager (SAM) files. Those files contain sensitive information including hashed domain and/or local credentials.

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214

Credential Acquisition via Registry Hive Dumping

Identifies attempts to export a registry hive which may contain credentials using the Windows reg.exe tool.

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211

Full User-Mode Dumps Enabled System-Wide

Identifies the enable of the full user-mode dumps feature system-wide. This feature allows Windows Error Reporting (WER) to collect data after an application crashes. This setting is a requirement for the LSASS Shtinkering attack, which fakes the communication of a crash on LSASS, generating a dump of the process memory, which gives the attacker access to the credentials present on the system without having to bring malware to the system. This setting is not enabled by default, and applications must create their registry subkeys to hold settings that enable them to collect dumps.

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8

Microsoft IIS Connection Strings Decryption

Identifies use of aspnet_regiis to decrypt Microsoft IIS connection strings. An attacker with Microsoft IIS web server access via a webshell or alike can decrypt and dump any hardcoded connection strings, such as the MSSQL service account password using aspnet_regiis command.

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211

Kerberos Traffic from Unusual Process

Identifies network connections to the standard Kerberos port from an unusual process. On Windows, the only process that normally performs Kerberos traffic from a domain joined host is lsass.exe.

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210

Kirbi File Creation

Identifies the creation of .kirbi files. The creation of this kind of file is an indicator of an attacker running Kerberos ticket dump utilities, such as Mimikatz, and precedes attacks such as Pass-The-Ticket (PTT), which allows the attacker to impersonate users using Kerberos tickets.

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210

Suspicious Module Loaded by LSASS

Identifies LSASS loading an unsigned or untrusted DLL. Windows Security Support Provider (SSP) DLLs are loaded into LSSAS process at system start. Once loaded into the LSA, SSP DLLs have access to encrypted and plaintext passwords that are stored in Windows, such as any logged-on user’s Domain password or smart card PINs.

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9

LSASS Memory Dump Creation

Identifies the creation of a Local Security Authority Subsystem Service (lsass.exe) default memory dump. This may indicate a credential access attempt via trusted system utilities such as Task Manager (taskmgr.exe) and SQL Dumper (sqldumper.exe) or known pentesting tools such as Dumpert and AndrewSpecial.

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211

Mimikatz Memssp Log File Detected

Identifies the password log file from the default Mimikatz memssp module.

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312

Modification of WDigest Security Provider

Identifies attempts to modify the WDigest security provider in the registry to force the user’s password to be stored in clear text in memory. This behavior can be indicative of an adversary attempting to weaken the security configuration of an endpoint. Once the UseLogonCredential value is modified, the adversary may attempt to dump clear text passwords from memory.

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111

Network Logon Provider Registry Modification

Identifies the modification of the network logon provider registry. Adversaries may register a rogue network logon provider module for persistence and/or credential access via intercepting the authentication credentials in clear text during user logon.

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112

Potential Local NTLM Relay via HTTP

Identifies attempt to coerce a local NTLM authentication via HTTP using the Windows Printer Spooler service as a target. An adversary may use this primitive in combination with other techniques to elevate privileges on a compromised system.

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210

Searching for Saved Credentials via VaultCmd

Windows Credential Manager allows you to create, view, or delete saved credentials for signing into websites, connected applications, and networks. An adversary may abuse this to list or dump credentials stored in the Credential Manager for saved usernames and passwords. This may also be performed in preparation of lateral movement.

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210

Symbolic Link to Shadow Copy Created

Identifies the creation of symbolic links to a shadow copy. Symbolic links can be used to access files in the shadow copy, including sensitive files such as ntds.dit, System Boot Key and browser offline credentials.

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212

Potential Veeam Credential Access Command

Identifies commands that can access and decrypt Veeam credentials stored in MSSQL databases. Attackers can use Veeam Credentials to target backups as part of destructive operations such as Ransomware attacks.

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102

NTDS Dump via Wbadmin

Identifies the execution of wbadmin to access the NTDS.dit file in a domain controller. Attackers with privileges from groups like Backup Operators can abuse the utility to perform credential access and compromise the domain.

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102

Wireless Credential Dumping using Netsh Command

Identifies attempts to dump Wireless saved access keys in clear text using the Windows built-in utility Netsh.

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109

Adding Hidden File Attribute via Attrib

Adversaries can add the hidden attribute to files to hide them from the user in an attempt to evade detection.

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213

Modification of AmsiEnable Registry Key

Identifies modifications of the AmsiEnable registry key to 0, which disables the Antimalware Scan Interface (AMSI). An adversary can modify this key to disable AMSI protections.

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212

Clearing Windows Console History

Identifies when a user attempts to clear console history. An adversary may clear the command history of a compromised account to conceal the actions undertaken during an intrusion.

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212

Clearing Windows Event Logs

Identifies attempts to clear or disable Windows event log stores using Windows wevetutil command. This is often done by attackers in an attempt to evade detection or destroy forensic evidence on a system.

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214

Code Signing Policy Modification Through Built-in tools

Identifies attempts to disable/modify the code signing policy through system native utilities. Code signing provides authenticity on a program, and grants the user with the ability to check whether the program has been tampered with. By allowing the execution of unsigned or self-signed code, threat actors can craft and execute malicious code.

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109

Code Signing Policy Modification Through Registry

Identifies attempts to disable the code signing policy through the registry. Code signing provides authenticity on a program, and grants the user with the ability to check whether the program has been tampered with. By allowing the execution of unsigned or self-signed code, threat actors can craft and execute malicious code.

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111

Creation or Modification of Root Certificate

Identifies the creation or modification of a local trusted root certificate in Windows. The install of a malicious root certificate would allow an attacker the ability to masquerade malicious files as valid signed components from any entity (for example, Microsoft). It could also allow an attacker to decrypt SSL traffic.

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211

Windows Defender Disabled via Registry Modification

Identifies modifications to the Windows Defender registry settings to disable the service or set the service to be started manually.

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115

Windows Defender Exclusions Added via PowerShell

Identifies modifications to the Windows Defender configuration settings using PowerShell to add exclusions at the folder directory or process level.

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212

Delete Volume USN Journal with Fsutil

Identifies use of the fsutil.exe to delete the volume USNJRNL. This technique is used by attackers to eliminate evidence of files created during post-exploitation activities.

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210

Network-Level Authentication (NLA) Disabled

Identifies the attempt to disable Network-Level Authentication (NLA) via registry modification. Network Level Authentication (NLA) is a feature on Windows that provides an extra layer of security for Remote Desktop (RDP) connections, as it requires users to authenticate before allowing a full RDP session. Attackers can disable NLA to enable persistence methods that require access to the Windows sign-in screen without authenticating, such as Accessibility Features persistence methods, like Sticky Keys.

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103

PowerShell Script Block Logging Disabled

Identifies attempts to disable PowerShell Script Block Logging via registry modification. Attackers may disable this logging to conceal their activities in the host and evade detection.

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210

Disable Windows Firewall Rules via Netsh

Identifies use of the netsh.exe to disable or weaken the local firewall. Attackers will use this command line tool to disable the firewall during troubleshooting or to enable network mobility.

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211

Disabling Windows Defender Security Settings via PowerShell

Identifies use of the Set-MpPreference PowerShell command to disable or weaken certain Windows Defender settings.

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212

Disable Windows Event and Security Logs Using Built-in Tools

Identifies attempts to disable EventLog via the logman Windows utility, PowerShell, or auditpol. This is often done by attackers in an attempt to evade detection on a system.

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213

DNS-over-HTTPS Enabled via Registry

Identifies when a user enables DNS-over-HTTPS. This can be used to hide internet activity or the process of exfiltrating data. With this enabled, an organization will lose visibility into data such as query type, response, and originating IP, which are used to determine bad actors.

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211

Suspicious .NET Code Compilation

Identifies executions of .NET compilers with suspicious parent processes, which can indicate an attacker’s attempt to compile code after delivery in order to bypass security mechanisms.

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211

Remote Desktop Enabled in Windows Firewall by Netsh

Identifies use of the network shell utility (netsh.exe) to enable inbound Remote Desktop Protocol (RDP) connections in the Windows Firewall.

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211

Enable Host Network Discovery via Netsh

Identifies use of the netsh.exe program to enable host discovery via the network. Attackers can use this command-line tool to weaken the host firewall settings.

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210

Control Panel Process with Unusual Arguments

Identifies unusual instances of Control Panel with suspicious keywords or paths in the process command line value. Adversaries may abuse control.exe to proxy execution of malicious code.

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212

ImageLoad via Windows Update Auto Update Client

Identifies abuse of the Windows Update Auto Update Client (wuauclt.exe) to load an arbitrary DLL. This behavior is used as a defense evasion technique to blend-in malicious activity with legitimate Windows software.

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213

Microsoft Build Engine Started by an Office Application

An instance of MSBuild, the Microsoft Build Engine, was started by Excel or Word. This is unusual behavior for the Build Engine and could have been caused by an Excel or Word document executing a malicious script payload.

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211

Microsoft Build Engine Started by a System Process

An instance of MSBuild, the Microsoft Build Engine, was started by Explorer or the WMI (Windows Management Instrumentation) subsystem. This behavior is unusual and is sometimes used by malicious payloads.

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211

Microsoft Build Engine Using an Alternate Name

An instance of MSBuild, the Microsoft Build Engine, was started after being renamed. This is uncommon behavior and may indicate an attempt to run unnoticed or undetected.

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113

Potential DLL Side-Loading via Trusted Microsoft Programs

Identifies an instance of a Windows trusted program that is known to be vulnerable to DLL Search Order Hijacking starting after being renamed or from a non-standard path. This is uncommon behavior and may indicate an attempt to evade defenses via side loading a malicious DLL within the memory space of one of those processes.

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111

Potential DLL Side-Loading via Microsoft Antimalware Service Executable

Identifies a Windows trusted program that is known to be vulnerable to DLL Search Order Hijacking starting after being renamed or from a non-standard path. This is uncommon behavior and may indicate an attempt to evade defenses via side-loading a malicious DLL within the memory space of one of those processes.

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111

Executable File Creation with Multiple Extensions

Masquerading can allow an adversary to evade defenses and better blend in with the environment. One way it occurs is when the name or location of a file is manipulated as a means of tricking a user into executing what they think is a benign file type but is actually executable code.

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209

Process Execution from an Unusual Directory

Identifies process execution from suspicious default Windows directories. This is sometimes done by adversaries to hide malware in trusted paths.

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212

Encoded Executable Stored in the Registry

Identifies registry write modifications to hide an encoded portable executable. This could be indicative of adversary defense evasion by avoiding the storing of malicious content directly on disk.

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311

IIS HTTP Logging Disabled

Identifies when Internet Information Services (IIS) HTTP Logging is disabled on a server. An attacker with IIS server access via a webshell or other mechanism can disable HTTP Logging as an effective anti-forensics measure.

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211

Suspicious Endpoint Security Parent Process

A suspicious Endpoint Security parent process was detected. This may indicate a process hollowing or other form of code injection.

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Renamed AutoIt Scripts Interpreter

Identifies a suspicious AutoIt process execution. Malware written as an AutoIt script tends to rename the AutoIt executable to avoid detection.

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111

Suspicious WerFault Child Process

A suspicious WerFault child process was detected, which may indicate an attempt to run via the SilentProcessExit registry key manipulation. Verify process details such as command line, network connections and file writes.

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315

Program Files Directory Masquerading

Identifies execution from a directory masquerading as the Windows Program Files directories. These paths are trusted and usually host trusted third party programs. An adversary may leverage masquerading, along with low privileges to bypass detections allowlisting those folders.

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211

Microsoft Windows Defender Tampering

Identifies when one or more features on Microsoft Defender are disabled. Adversaries may disable or tamper with Microsoft Defender features to evade detection and conceal malicious behavior.

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214

MS Office Macro Security Registry Modifications

Microsoft Office Products offer options for users and developers to control the security settings for running and using Macros. Adversaries may abuse these security settings to modify the default behavior of the Office Application to trust future macros and/or disable security warnings, which could increase their chances of establishing persistence.

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208

Windows Firewall Disabled via PowerShell

Identifies when the Windows Firewall is disabled using PowerShell cmdlets, which can help attackers evade network constraints, like internet and network lateral communication restrictions.

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210

Suspicious Microsoft Diagnostics Wizard Execution

Identifies potential abuse of the Microsoft Diagnostics Troubleshooting Wizard (MSDT) to proxy malicious command or binary execution via malicious process arguments.

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110

DNS Global Query Block List Modified or Disabled

Identifies changes to the DNS Global Query Block List (GQBL), a security feature that prevents the resolution of certain DNS names often exploited in attacks like WPAD spoofing. Attackers with certain privileges, such as DNSAdmins, can modify or disable the GQBL, allowing exploitation of hosts running WPAD with default settings for privilege escalation and lateral movement.

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103

Alternate Data Stream Creation/Execution at Volume Root Directory

Identifies the creation of an Alternate Data Stream (ADS) at a volume root directory, which can indicate the attempt to hide tools and malware, as ADSs created in this directory are not displayed by system utilities.

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101

Scheduled Tasks AT Command Enabled

Identifies attempts to enable the Windows scheduled tasks AT command via the registry. Attackers may use this method to move laterally or persist locally. The AT command has been deprecated since Windows 8 and Windows Server 2012, but still exists for backwards compatibility.

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210

Potential Secure File Deletion via SDelete Utility

Detects file name patterns generated by the use of Sysinternals SDelete utility to securely delete a file via multiple file overwrite and rename operations.

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209

SIP Provider Modification

Identifies modifications to the registered Subject Interface Package (SIP) providers. SIP providers are used by the Windows cryptographic system to validate file signatures on the system. This may be an attempt to bypass signature validation checks or inject code into critical processes.

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209

SolarWinds Process Disabling Services via Registry

Identifies a SolarWinds binary modifying the start type of a service to be disabled. An adversary may abuse this technique to manipulate relevant security services.

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211

Suspicious CertUtil Commands

Identifies suspicious commands being used with certutil.exe. CertUtil is a native Windows component which is part of Certificate Services. CertUtil is often abused by attackers to live off the land for stealthier command and control or data exfiltration.

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210

Suspicious Managed Code Hosting Process

Identifies a suspicious managed code hosting process which could indicate code injection or other form of suspicious code execution.

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208

Suspicious Script Object Execution

Identifies scrobj.dll loaded into unusual Microsoft processes. This usually means a malicious scriptlet is being executed in the target process.

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109

Renamed Utility Executed with Short Program Name

Identifies the execution of a process with a single character process name, differing from the original file name. This is often done by adversaries while staging, executing temporary utilities, or trying to bypass security detections based on the process name.

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110

Unusual Executable File Creation by a System Critical Process

Identifies an unexpected executable file being created or modified by a Windows system critical process, which may indicate activity related to remote code execution or other forms of exploitation.

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211

Unusual File Creation - Alternate Data Stream

Identifies suspicious creation of Alternate Data Streams on highly targeted files. This is uncommon for legitimate files and sometimes done by adversaries to hide malware.

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Unusual Process Execution Path - Alternate Data Stream

Identifies processes running from an Alternate Data Stream. This is uncommon for legitimate processes and sometimes done by adversaries to hide malware.

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209

Unusual Child Process from a System Virtual Process

Identifies a suspicious child process of the Windows virtual system process, which could indicate code injection.

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211

Signed Proxy Execution via MS Work Folders

Identifies the use of Windows Work Folders to execute a potentially masqueraded control.exe file in the current working directory. Misuse of Windows Work Folders could indicate malicious activity.

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209

Suspicious Execution via Windows Subsystem for Linux

Detects Linux Bash commands from the the Windows Subsystem for Linux. Adversaries may enable and use WSL for Linux to avoid detection.

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107

Execution via Windows Subsystem for Linux

Detects attempts to execute a program on the host from the Windows Subsystem for Linux. Adversaries may enable and use WSL for Linux to avoid detection.

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107

Windows Subsystem for Linux Enabled via Dism Utility

Detects attempts to enable the Windows Subsystem for Linux using Microsoft Dism utility. Adversaries may enable and use WSL for Linux to avoid detection.

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108

Attempt to Install Kali Linux via WSL

Detects attempts to install or use Kali Linux via Windows Subsystem for Linux. Adversaries may enable and use WSL for Linux to avoid detection.

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108

Windows Subsystem for Linux Distribution Installed

Detects changes to the registry that indicates the install of a new Windows Subsystem for Linux distribution by name. Adversaries may enable and use WSL for Linux to avoid detection.

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108

AdFind Command Activity

This rule detects the Active Directory query tool, AdFind.exe. AdFind has legitimate purposes, but it is frequently leveraged by threat actors to perform post-exploitation Active Directory reconnaissance. The AdFind tool has been observed in Trickbot, Ryuk, Maze, and FIN6 campaigns. For Winlogbeat, this rule requires Sysmon.

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213

Enumeration of Administrator Accounts

Identifies instances of lower privilege accounts enumerating Administrator accounts or groups using built-in Windows tools.

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114

Enumerating Domain Trusts via DSQUERY.EXE

Identifies the use of dsquery.exe for domain trust discovery purposes. Adversaries may use this command-line utility to enumerate trust relationships that may be used for Lateral Movement opportunities in Windows multi-domain forest environments.

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109

Enumerating Domain Trusts via NLTEST.EXE

Identifies the use of nltest.exe for domain trust discovery purposes. Adversaries may use this command-line utility to enumerate domain trusts and gain insight into trust relationships, as well as the state of Domain Controller (DC) replication in a Microsoft Windows NT Domain.

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113

Group Policy Discovery via Microsoft GPResult Utility

Detects the usage of gpresult.exe to query group policy objects. Attackers may query group policy objects during the reconnaissance phase after compromising a system to gain a better understanding of the active directory environment and possible methods to escalate privileges or move laterally.

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109

Peripheral Device Discovery

Identifies use of the Windows file system utility (fsutil.exe) to gather information about attached peripheral devices and components connected to a computer system.

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210

Command Execution via SolarWinds Process

A suspicious SolarWinds child process (Cmd.exe or Powershell.exe) was detected.

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212

Suspicious SolarWinds Child Process

A suspicious SolarWinds child process was detected, which may indicate an attempt to execute malicious programs.

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210

Execution of COM object via Xwizard

Windows Component Object Model (COM) is an inter-process communication (IPC) component of the native Windows application programming interface (API) that enables interaction between software objects or executable code. Xwizard can be used to run a COM object created in registry to evade defensive counter measures.

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210

Svchost spawning Cmd

Identifies a suspicious parent child process relationship with cmd.exe descending from svchost.exe

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217

Command Shell Activity Started via RunDLL32

Identifies command shell activity started via RunDLL32, which is commonly abused by attackers to host malicious code.

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210

Enumeration Command Spawned via WMIPrvSE

Identifies native Windows host and network enumeration commands spawned by the Windows Management Instrumentation Provider Service (WMIPrvSE).

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213

Execution from Unusual Directory - Command Line

Identifies process execution from suspicious default Windows directories. This may be abused by adversaries to hide malware in trusted paths.

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214

Unusual Execution via Microsoft Common Console File

Identifies the execution of a child process from a Microsoft Common Console file. Adversaries may embed a malicious command in an MSC file in order to trick victims into executing malicious commands.

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101

Mofcomp Activity

Managed Object Format (MOF) files can be compiled locally or remotely through mofcomp.exe. Attackers may leverage MOF files to build their own namespaces and classes into the Windows Management Instrumentation (WMI) repository, or establish persistence using WMI Event Subscription.

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Execution via local SxS Shared Module

Identifies the creation, change, or deletion of a DLL module within a Windows SxS local folder. Adversaries may abuse shared modules to execute malicious payloads by instructing the Windows module loader to load DLLs from arbitrary local paths.

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208

Suspicious Cmd Execution via WMI

Identifies suspicious command execution (cmd) via Windows Management Instrumentation (WMI) on a remote host. This could be indicative of adversary lateral movement.

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213

Suspicious PDF Reader Child Process

Identifies suspicious child processes of PDF reader applications. These child processes are often launched via exploitation of PDF applications or social engineering.

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211

Suspicious Process Execution via Renamed PsExec Executable

Identifies suspicious psexec activity which is executing from the psexec service that has been renamed, possibly to evade detection.

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Process Activity via Compiled HTML File

Compiled HTML files (.chm) are commonly distributed as part of the Microsoft HTML Help system. Adversaries may conceal malicious code in a CHM file and deliver it to a victim for execution. CHM content is loaded by the HTML Help executable program (hh.exe).

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211

Conhost Spawned By Suspicious Parent Process

Detects when the Console Window Host (conhost.exe) process is spawned by a suspicious parent process, which could be indicative of code injection.

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210

Rare SMB Connection to the Internet

This rule detects rare internet network connections via the SMB protocol. SMB is commonly used to leak NTLM credentials via rogue UNC path injection.

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Third-party Backup Files Deleted via Unexpected Process

Identifies the deletion of backup files, saved using third-party software, by a process outside of the backup suite. Adversaries may delete Backup files to ensure that recovery from a ransomware attack is less likely.

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213

Deleting Backup Catalogs with Wbadmin

Identifies use of the wbadmin.exe to delete the backup catalog. Ransomware and other malware may do this to prevent system recovery.

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213

Potential Ransomware Behavior - High count of Readme files by System

This rule identifies a high number (20) of file creation event by the System virtual process from the same host and with same file name containing keywords similar to ransomware note files and all within a short time period.

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Modification of Boot Configuration

Identifies use of bcdedit.exe to delete boot configuration data. This tactic is sometimes used as by malware or an attacker as a destructive technique.

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210

Volume Shadow Copy Deleted or Resized via VssAdmin

Identifies use of vssadmin.exe for shadow copy deletion or resizing on endpoints. This commonly occurs in tandem with ransomware or other destructive attacks.

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212

Volume Shadow Copy Deletion via PowerShell

Identifies the use of the Win32_ShadowCopy class and related cmdlets to achieve shadow copy deletion. This commonly occurs in tandem with ransomware or other destructive attacks.

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212

Volume Shadow Copy Deletion via WMIC

Identifies use of wmic.exe for shadow copy deletion on endpoints. This commonly occurs in tandem with ransomware or other destructive attacks.

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211

Suspicious Execution from INET Cache

Identifies the execution of a process with arguments pointing to the INetCache Folder. Adversaries may deliver malicious content via WININET during initial access.

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103

Suspicious Execution via Microsoft Office Add-Ins

Identifies execution of common Microsoft Office applications to launch an Office Add-In from a suspicious path or with an unusual parent process. This may indicate an attempt to get initial access via a malicious phishing MS Office Add-In.

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105

First Time Seen Removable Device

Identifies newly seen removable devices by device friendly name using registry modification events. While this activity is not inherently malicious, analysts can use those events to aid monitoring for data exfiltration over those devices.

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Suspicious JetBrains TeamCity Child Process

Identifies suspicious processes being spawned by the JetBrain TeamCity process. This activity could be related to JetBrains remote code execution vulnerabilities.

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103

Windows Script Executing PowerShell

Identifies a PowerShell process launched by either cscript.exe or wscript.exe. Observing Windows scripting processes executing a PowerShell script, may be indicative of malicious activity.

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212

Microsoft Exchange Server UM Writing Suspicious Files

Identifies suspicious files being written by the Microsoft Exchange Server Unified Messaging (UM) service. This activity has been observed exploiting CVE-2021-26858.

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Microsoft Exchange Server UM Spawning Suspicious Processes

Identifies suspicious processes being spawned by the Microsoft Exchange Server Unified Messaging (UM) service. This activity has been observed exploiting CVE-2021-26857.

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210

Microsoft Exchange Worker Spawning Suspicious Processes

Identifies suspicious processes being spawned by the Microsoft Exchange Server worker process (w3wp). This activity may indicate exploitation activity or access to an existing web shell backdoor.

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209

Suspicious MS Office Child Process

Identifies suspicious child processes of frequently targeted Microsoft Office applications (Word, PowerPoint, Excel). These child processes are often launched during exploitation of Office applications or from documents with malicious macros.

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213

Suspicious Explorer Child Process

Identifies a suspicious Windows explorer child process. Explorer.exe can be abused to launch malicious scripts or executables from a trusted parent process.

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209

ScreenConnect Server Spawning Suspicious Processes

Identifies suspicious processes being spawned by the ScreenConnect server process (ScreenConnect.Service.exe). This activity may indicate exploitation activity or access to an existing web shell backdoor.

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102

NullSessionPipe Registry Modification

Identifies NullSessionPipe registry modifications that specify which pipes can be accessed anonymously. This could be indicative of adversary lateral movement preparation by making the added pipe available to everyone.

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210

Potential Remote Desktop Shadowing Activity

Identifies the modification of the Remote Desktop Protocol (RDP) Shadow registry or the execution of processes indicative of an active RDP shadowing session. An adversary may abuse the RDP Shadowing feature to spy on or control other users active RDP sessions.

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209

Execution via TSClient Mountpoint

Identifies execution from the Remote Desktop Protocol (RDP) shared mountpoint tsclient on the target host. This may indicate a lateral movement attempt.

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211

Mounting Hidden or WebDav Remote Shares

Identifies the use of net.exe to mount a WebDav or hidden remote share. This may indicate lateral movement or preparation for data exfiltration.

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210

RDP Enabled via Registry

Identifies registry write modifications to enable Remote Desktop Protocol (RDP) access. This could be indicative of adversary lateral movement preparation.

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212

Remote File Copy to a Hidden Share

Identifies a remote file copy attempt to a hidden network share. This may indicate lateral movement or data staging activity.

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211

Unusual Child Process of dns.exe

Identifies an unexpected process spawning from dns.exe, the process responsible for Windows DNS server services, which may indicate activity related to remote code execution or other forms of exploitation.

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211

Lateral Movement via Startup Folder

Identifies suspicious file creations in the startup folder of a remote system. An adversary could abuse this to move laterally by dropping a malicious script or executable that will be executed after a reboot or user logon.

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209

Installation of Custom Shim Databases

Identifies the installation of custom Application Compatibility Shim databases. This Windows functionality has been abused by attackers to stealthily gain persistence and arbitrary code execution in legitimate Windows processes.

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209

Registry Persistence via AppInit DLL

AppInit DLLs are dynamic-link libraries (DLLs) that are loaded into every process that creates a user interface (loads user32.dll) on Microsoft Windows operating systems. The AppInit DLL mechanism is used to load custom code into user-mode processes, allowing for the customization of the user interface and the behavior of Windows-based applications. Attackers who add those DLLs to the registry locations can execute code with elevated privileges, similar to process injection, and provide a solid and constant persistence on the machine.

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211

Browser Extension Install

Identifies the install of browser extensions. Malicious browser extensions can be installed via app store downloads masquerading as legitimate extensions, social engineering, or by an adversary that has already compromised a system.

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102

Creation of a Hidden Local User Account

Identifies the creation of a hidden local user account by appending the dollar sign to the account name. This is sometimes done by attackers to increase access to a system and avoid appearing in the results of accounts listing using the net users command.

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211

Image File Execution Options Injection

The Debugger and SilentProcessExit registry keys can allow an adversary to intercept the execution of files, causing a different process to be executed. This functionality can be abused by an adversary to establish persistence.

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209

Suspicious Startup Shell Folder Modification

Identifies suspicious startup shell folder modifications to change the default Startup directory in order to bypass detections monitoring file creation in the Windows Startup folder.

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213

Persistence via Scheduled Job Creation

A job can be used to schedule programs or scripts to be executed at a specified date and time. Adversaries may abuse task scheduling functionality to facilitate initial or recurring execution of malicious code.

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311

Persistence via Microsoft Office AddIns

Detects attempts to establish persistence on an endpoint by abusing Microsoft Office add-ins.

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208

Persistence via Microsoft Outlook VBA

Detects attempts to establish persistence on an endpoint by installing a rogue Microsoft Outlook VBA Template.

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207

Office Test Registry Persistence

Identifies the modification of the Microsoft Office "Office Test" Registry key, a registry location that can be used to specify a DLL which will be executed every time an MS Office application is started. Attackers can abuse this to gain persistence on a compromised host.

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103

Netsh Helper DLL

Identifies the addition of a Netsh Helper DLL, netsh.exe supports the addition of these DLLs to extend its functionality. Attackers may abuse this mechanism to execute malicious payloads every time the utility is executed, which can be done by administrators or a scheduled task.

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102

New ActiveSyncAllowedDeviceID Added via PowerShell

Identifies the use of the Exchange PowerShell cmdlet, Set-CASMailbox, to add a new ActiveSync allowed device. Adversaries may target user email to collect sensitive information.

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210

Persistence via PowerShell profile

Identifies the creation or modification of a PowerShell profile. PowerShell profile is a script that is executed when PowerShell starts to customize the user environment, which can be abused by attackers to persist in a environment where PowerShell is common.

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109

Potential Modification of Accessibility Binaries

Windows contains accessibility features that may be launched with a key combination before a user has logged in. An adversary can modify the way these programs are launched to get a command prompt or backdoor without logging in to the system.

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112

Unusual Persistence via Services Registry

Identifies processes modifying the services registry key directly, instead of through the expected Windows APIs. This could be an indication of an adversary attempting to stealthily persist through abnormal service creation or modification of an existing service.

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210

Startup Persistence by a Suspicious Process

Identifies files written to or modified in the startup folder by commonly abused processes. Adversaries may use this technique to maintain persistence.

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211

Persistent Scripts in the Startup Directory

Identifies script engines creating files in the Startup folder, or the creation of script files in the Startup folder. Adversaries may abuse this technique to maintain persistence in an environment.

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212

Suspicious ImagePath Service Creation

Identifies the creation of a suspicious ImagePath value. This could be an indication of an adversary attempting to stealthily persist or escalate privileges through abnormal service creation.

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209

Potential Persistence via Time Provider Modification

Identifies modification of the Time Provider. Adversaries may establish persistence by registering and enabling a malicious DLL as a time provider. Windows uses the time provider architecture to obtain accurate time stamps from other network devices or clients in the network. Time providers are implemented in the form of a DLL file which resides in the System32 folder. The service W32Time initiates during the startup of Windows and loads w32time.dll.

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211

User Account Creation

Identifies attempts to create new users. This is sometimes done by attackers to increase access or establish persistence on a system or domain.

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210

Potential Application Shimming via Sdbinst

The Application Shim was created to allow for backward compatibility of software as the operating system codebase changes over time. This Windows functionality has been abused by attackers to stealthily gain persistence and arbitrary code execution in legitimate Windows processes.

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211

Persistence via BITS Job Notify Cmdline

An adversary can use the Background Intelligent Transfer Service (BITS) SetNotifyCmdLine method to execute a program that runs after a job finishes transferring data or after a job enters a specified state in order to persist on a system.

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310

Installation of Security Support Provider

Identifies registry modifications related to the Windows Security Support Provider (SSP) configuration. Adversaries may abuse this to establish persistence in an environment.

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209

Persistence via TelemetryController Scheduled Task Hijack

Detects the successful hijack of Microsoft Compatibility Appraiser scheduled task to establish persistence with an integrity level of system.

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211

Persistence via Update Orchestrator Service Hijack

Identifies potential hijacking of the Microsoft Update Orchestrator Service to establish persistence with an integrity level of SYSTEM.

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211

Persistence via WMI Event Subscription

An adversary can use Windows Management Instrumentation (WMI) to install event filters, providers, consumers, and bindings that execute code when a defined event occurs. Adversaries may use the capabilities of WMI to subscribe to an event and execute arbitrary code when that event occurs, providing persistence on a system.

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212

Execution via MSSQL xp_cmdshell Stored Procedure

Identifies execution via MSSQL xp_cmdshell stored procedure. Malicious users may attempt to elevate their privileges by using xp_cmdshell, which is disabled by default, thus, it’s important to review the context of it’s use.

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212

Web Shell Detection: Script Process Child of Common Web Processes

Identifies suspicious commands executed via a web server, which may suggest a vulnerability and remote shell access.

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315

Werfault ReflectDebugger Persistence

Identifies the registration of a Werfault Debugger. Attackers may abuse this mechanism to execute malicious payloads every time the utility is executed with the "-pr" parameter.

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102

Disabling User Account Control via Registry Modification

User Account Control (UAC) can help mitigate the impact of malware on Windows hosts. With UAC, apps and tasks always run in the security context of a non-administrator account, unless an administrator specifically authorizes administrator-level access to the system. This rule identifies registry value changes to bypass User Access Control (UAC) protection.

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212

Potential privilege escalation via CVE-2022-38028

Identifies a privilege escalation attempt via exploiting CVE-2022-38028 to hijack the print spooler service execution.

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103

Creation or Modification of a new GPO Scheduled Task or Service

Detects the creation or modification of a new Group Policy based scheduled task or service. These methods are used for legitimate system administration, but can also be abused by an attacker with domain admin permissions to execute a malicious payload remotely on all or a subset of the domain joined machines.

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210

Potential LSA Authentication Package Abuse

Adversaries can use the autostart mechanism provided by the Local Security Authority (LSA) authentication packages for privilege escalation or persistence by placing a reference to a binary in the Windows registry. The binary will then be executed by SYSTEM when the authentication packages are loaded.

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106

Privilege Escalation via Named Pipe Impersonation

Identifies a privilege escalation attempt via named pipe impersonation. An adversary may abuse this technique by utilizing a framework such Metasploit’s meterpreter getsystem command.

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211

Suspicious DLL Loaded for Persistence or Privilege Escalation

Identifies the loading of a non Microsoft signed DLL that is missing on a default Windows install (phantom DLL) or one that can be loaded from a different location by a native Windows process. This may be abused to persist or elevate privileges via privileged file write vulnerabilities.

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113

Potential Port Monitor or Print Processor Registration Abuse

Identifies port monitor and print processor registry modifications. Adversaries may abuse port monitor and print processors to run malicious DLLs during system boot that will be executed as SYSTEM for privilege escalation and/or persistence, if permissions allow writing a fully-qualified pathname for that DLL.

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108

Suspicious PrintSpooler Service Executable File Creation

Detects attempts to exploit privilege escalation vulnerabilities related to the Print Spooler service. For more information refer to the following CVE’s - CVE-2020-1048, CVE-2020-1337 and CVE-2020-1300 and verify that the impacted system is patched.

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113

Suspicious Print Spooler File Deletion

Detects deletion of print driver files by an unusual process. This may indicate a clean up attempt post successful privilege escalation via Print Spooler service related vulnerabilities.

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207

Suspicious Print Spooler SPL File Created

Detects attempts to exploit privilege escalation vulnerabilities related to the Print Spooler service including CVE-2020-1048 and CVE-2020-1337.

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113

Privilege Escalation via Windir Environment Variable

Identifies a privilege escalation attempt via a rogue Windows directory (Windir) environment variable. This is a known primitive that is often combined with other vulnerabilities to elevate privileges.

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208

Service Control Spawned via Script Interpreter

Identifies Service Control (sc.exe) spawning from script interpreter processes to create, modify, or start services. This can potentially indicate an attempt to elevate privileges or maintain persistence.

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112

UAC Bypass Attempt with IEditionUpgradeManager Elevated COM Interface

Identifies attempts to bypass User Account Control (UAC) by abusing an elevated COM Interface to launch a rogue Windows ClipUp program. Attackers may attempt to bypass UAC to stealthily execute code with elevated permissions.

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209

UAC Bypass Attempt via Elevated COM Internet Explorer Add-On Installer

Identifies User Account Control (UAC) bypass attempts by abusing an elevated COM Interface to launch a malicious program. Attackers may attempt to bypass UAC to stealthily execute code with elevated permissions.

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209

UAC Bypass via ICMLuaUtil Elevated COM Interface

Identifies User Account Control (UAC) bypass attempts via the ICMLuaUtil Elevated COM interface. Attackers may attempt to bypass UAC to stealthily execute code with elevated permissions.

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110

UAC Bypass via DiskCleanup Scheduled Task Hijack

Identifies User Account Control (UAC) bypass via hijacking DiskCleanup Scheduled Task. Attackers bypass UAC to stealthily execute code with elevated permissions.

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210

UAC Bypass Attempt via Privileged IFileOperation COM Interface

Identifies attempts to bypass User Account Control (UAC) via DLL side-loading. Attackers may attempt to bypass UAC to stealthily execute code with elevated permissions.

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209

Bypass UAC via Event Viewer

Identifies User Account Control (UAC) bypass via eventvwr.exe. Attackers bypass UAC to stealthily execute code with elevated permissions.

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214

UAC Bypass Attempt via Windows Directory Masquerading

Identifies an attempt to bypass User Account Control (UAC) by masquerading as a Microsoft trusted Windows directory. Attackers may bypass UAC to stealthily execute code with elevated permissions.

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214

UAC Bypass via Windows Firewall Snap-In Hijack

Identifies attempts to bypass User Account Control (UAC) by hijacking the Microsoft Management Console (MMC) Windows Firewall snap-in. Attackers bypass UAC to stealthily execute code with elevated permissions.

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212

Potential Exploitation of an Unquoted Service Path Vulnerability

Adversaries may leverage unquoted service path vulnerabilities to escalate privileges. By placing an executable in a higher-level directory within the path of an unquoted service executable, Windows will natively launch this executable from its defined path variable instead of the benign one in a deeper directory, thus leading to code execution.

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103

Unusual Parent-Child Relationship

Identifies Windows programs run from unexpected parent processes. This could indicate masquerading or other strange activity on a system.

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213

Unusual Service Host Child Process - Childless Service

Identifies unusual child processes of Service Host (svchost.exe) that traditionally do not spawn any child processes. This may indicate a code injection or an equivalent form of exploitation.

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210