Update v8.12.19

AWS IAM CompromisedKeyQuarantine Policy Attached to User

This rule looks for use of the IAM AttachUserPolicy API operation to attach the CompromisedKeyQuarantine or CompromisedKeyQuarantineV2 AWS managed policies to an existing IAM user. This policy denies access to certain actions and is applied by the AWS team in the event that an IAM user’s credentials have been compromised or exposed publicly.

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First Time AWS Cloudformation Stack Creation by User

This rule detects the first time a principal calls AWS Cloudwatch CreateStack or CreateStackSet API. Cloudformation is used to create a single collection of cloud resources called a stack, via a defined template file. An attacker with the appropriate privileges could leverage Cloudformation to create specific resources needed to further exploit the environment. This is a new terms rule that looks for the first instance of this behavior in the last 10 days for a role or IAM user within a particular account.

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AWS EC2 Instance Console Login via Assumed Role

Identifies a successful console login activity by an EC2 instance profile using an assumed role. This is uncommon behavior and could indicate an attacker using compromised credentials to further exploit an environment. An EC2 instance assumes a role using their EC2 ID as the session name. This rule looks for the pattern "i-" which is the beginning pattern for assumed role sessions started by an EC2 instance and a successful ConsoleLogin or GetSigninToken API call.

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AWS EC2 Instance Interaction with IAM Service

Identifies when an EC2 instance interacts with the AWS IAM service via an assumed role. This is uncommon behavior and could indicate an attacker using compromised credentials to further exploit an environment. For example, an assumed role could be used to create new users for persistence or add permissions for privilege escalation. An EC2 instance assumes a role using their EC2 ID as the session name. This rule looks for the pattern "i-" which is the beginning pattern for assumed role sessions started by an EC2 instance.

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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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Potential Active Directory Replication Account Backdoor

Identifies the modification of the nTSecurityDescriptor attribute in a domain object with rights related to DCSync to a user/computer account. Attackers can use this backdoor to re-obtain access to hashes of any user/computer.

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Potential Relay Attack against a Domain Controller

Identifies potential relay attacks against a domain controller (DC) by identifying authentication events using the domain controller computer account coming from other hosts to the DC that owns the account. Attackers may relay the DC hash after capturing it using forced authentication.

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AWS S3 Object Versioning Suspended

Identifies when object versioning is suspended for an Amazon S3 bucket. Object versioning allows for multiple versions of an object to exist in the same bucket. This allows for easy recovery of deleted or overwritten objects. When object versioning is suspended for a bucket, it could indicate an adversary’s attempt to inhibit system recovery following malicious activity. Additionally, when versioning is suspended, buckets can then be deleted.

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System Binary Moved or Copied

This rule monitors for the copying or moving of a system binary. Adversaries may copy/move and rename system binaries to evade detection. Copying a system binary to a different location should not occur often, so if it does, the activity should be investigated.

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Executable Bit Set for Potential Persistence Script

This rule monitors for the addition of an executable bit for scripts that are located in directories which are commonly abused for persistence. An alert of this rule is an indicator that a persistence mechanism is being set up within your environment. Adversaries may create these scripts to execute malicious code at start-up, or at a set interval to gain persistence onto the system.

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Suspicious Symbolic Link Created

Identifies the creation of a symbolic link to a suspicious file or location. A symbolic link is a reference to a file or directory that acts as a pointer or shortcut, allowing users to access the target file or directory from a different location in the file system. An attacker can potentially leverage symbolic links for privilege escalation by tricking a privileged process into following the symbolic link to a sensitive file, giving the attacker access to data or capabilities they would not normally have.

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Potential Suspicious DebugFS Root Device Access

This rule monitors for the usage of the built-in Linux DebugFS utility to access a disk device without root permissions. Linux users that are part of the "disk" group have sufficient privileges to access all data inside of the machine through DebugFS. Attackers may leverage DebugFS in conjunction with "disk" permissions to read sensitive files owned by root, such as the shadow file, root ssh private keys or other sensitive files that may allow them to further escalate privileges.

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Accepted Default Telnet Port Connection

This rule detects network events that may indicate the use of Telnet traffic. Telnet is commonly used by system administrators to remotely control older or embedded systems using the command line shell. It should almost never be directly exposed to the Internet, as it is frequently targeted and exploited by threat actors as an initial access or backdoor vector. As a plain-text protocol, it may also expose usernames and passwords to anyone capable of observing the traffic.

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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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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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Sensitive Registry Hive Access via RegBack

Identifies attempts to access sensitive registry hives which contain credentials from the registry backup folder.

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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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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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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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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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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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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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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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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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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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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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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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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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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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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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Potential SharpRDP Behavior

Identifies potential behavior of SharpRDP, which is a tool that can be used to perform authenticated command execution against a remote target via Remote Desktop Protocol (RDP) for the purposes of lateral movement.

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Remote Scheduled Task Creation

Identifies remote scheduled task creations on a target host. This could be indicative of adversary lateral movement.

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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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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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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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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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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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Scheduled Task Created by a Windows Script

A scheduled task was created by a Windows script via cscript.exe, wscript.exe or powershell.exe. This can be abused by an adversary to establish persistence.

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Uncommon Registry Persistence Change

Detects changes to registry persistence keys that are not commonly used or modified by legitimate programs. This could be an indication of an adversary’s attempt to persist in a stealthy manner.

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Startup or Run Key Registry Modification

Identifies run key or startup key registry modifications. In order to survive reboots and other system interrupts, attackers will modify run keys within the registry or leverage startup folder items as a form of persistence.

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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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Component Object Model Hijacking

Identifies Component Object Model (COM) hijacking via registry modification. Adversaries may establish persistence by executing malicious content triggered by hijacked references to COM objects.

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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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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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Persistence via Hidden Run Key Detected

Identifies a persistence mechanism that utilizes the NtSetValueKey native API to create a hidden (null terminated) registry key. An adversary may use this method to hide from system utilities such as the Registry Editor (regedit).

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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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Persistence via WMI Standard Registry Provider

Identifies use of the Windows Management Instrumentation StdRegProv (registry provider) to modify commonly abused registry locations for persistence.

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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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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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