Sigma Rules
137 rules found
Mail Forwarding/Redirecting Activity In O365
Detects email forwarding or redirecting activity in O365 Audit logs.
Inbox Rules Creation Or Update Activity in O365
Detects inbox rule creation or update via O365 Audit logs, a technique commonly observed in Business Email Compromise (BEC) attacks to hide emails. The usage of inbox rules can be a sign of a compromised mailbox, where an attacker is attempting to evade detections by suppressing or redirecting incoming emails. Analysts should review these rules in context, validate whether they reflect normal user behavior, and correlate with other indicators such as unusual login activity or recent mailbox rule modifications.
Okta Password Health Report Query
Detects all activities against the endpoint "/reports/password-health/*" which should only be accessed via OKTA Admin Console UI. Use this rule to hunt for potential suspicious requests. Correlate this event with "admin console" login and alert on requests without any corresponding admin console login
Python Path Configuration File Creation - Linux
Detects creation of a Python path configuration file (.pth) in Python library folders, which can be maliciously abused for code execution and persistence. Modules referenced by these files are run at every Python startup (v3.5+), regardless of whether the module is imported by the calling script. Default paths are '\lib\site-packages\*.pth' (Windows) and '/lib/pythonX.Y/site-packages/*.pth' (Unix and macOS).
Potentially Suspicious Long Filename Pattern - Linux
Detects the creation of files with unusually long filenames (100 or more characters), which may indicate obfuscation techniques used by malware such as VShell. This is a hunting rule to identify potential threats that use long filenames to evade detection. Keep in mind that on a legitimate system, such long filenames can and are common. Run this detection in the context of threat hunting rather than alerting. Adjust the threshold of filename length as needed based on your environment.
Terminate Linux Process Via Kill
Detects usage of command line tools such as "kill", "pkill" or "killall" to terminate or signal a running process.
Process Discovery
Detects process discovery commands. Adversaries may attempt to get information about running processes on a system. Information obtained could be used to gain an understanding of common software/applications running on systems within the network
Python Path Configuration File Creation - MacOS
Detects creation of a Python path configuration file (.pth) in Python library folders, which can be maliciously abused for code execution and persistence. Modules referenced by these files are run at every Python startup (v3.5+), regardless of whether the module is imported by the calling script. Default paths are '\lib\site-packages\*.pth' (Windows) and '/lib/pythonX.Y/site-packages/*.pth' (Unix and macOS).
Clipboard Data Collection Via Pbpaste
Detects execution of the "pbpaste" utility, which retrieves the contents of the clipboard (a.k.a. pasteboard) and writes them to the standard output (stdout). The utility is often used for creating new files with the clipboard content or for piping clipboard contents to other commands. It can also be used in shell scripts that may require clipboard content as input. Attackers can abuse this utility in order to collect data from the user clipboard, which may contain passwords or sensitive information. Use this rule to hunt for potential abuse of the utility by looking at the parent process and any potentially suspicious command line content.
Low Reputation Effective Top-Level Domain (eTLD)
Detects DNS queries to domains within known low reputation eTLDs. This rule uses AlphaSOC's threat intelligence data and is updated on a monthly basis.
.Class Extension URI Ending Request
Detects requests to URI ending with the ".class" extension in proxy logs. This could rules can be used to hunt for potential downloads of Java classes as seen for example in Log4shell exploitation attacks against Log4j.
Successful MSIX/AppX Package Installation
Detects successful MSIX/AppX package installations on Windows systems by monitoring EventID 854 in the Microsoft-Windows-AppXDeployment-Server/Operational log. While most installations are legitimate, this can help identify unauthorized or suspicious package installations. It is crucial to monitor such events as threat actors may exploit MSIX/AppX packages to deliver and execute malicious payloads.
Firewall Rule Modified In The Windows Firewall Exception List
Detects when a rule has been modified in the Windows firewall exception list
Potential Remote WMI ActiveScriptEventConsumers Activity
Detect potential adversaries leveraging WMI ActiveScriptEventConsumers remotely to move laterally in a network. This event is best correlated and used as an enrichment to determine the potential lateral movement activity.
Access To Browser Credential Files By Uncommon Applications - Security
Detects file access requests to browser credential stores by uncommon processes. Could indicate potential attempt of credential stealing This rule requires heavy baselining before usage.
Scheduled Task Deletion
Detects scheduled task deletion events. Scheduled tasks are likely to be deleted if not used for persistence. Malicious Software often creates tasks directly under the root node e.g. \TASKNAME
CreateRemoteThread API and LoadLibrary
Detects potential use of CreateRemoteThread api and LoadLibrary function to inject DLL into a process
Remote Thread Creation Via PowerShell
Detects the creation of a remote thread from a Powershell process to another process
Remote Thread Created In Shell Application
Detects remote thread creation in command shell applications, such as "Cmd.EXE" and "PowerShell.EXE". It is a common technique used by malware, such as IcedID, to inject malicious code and execute it within legitimate processes.
Access To Chromium Browsers Sensitive Files By Uncommon Applications
Detects file access requests to chromium based browser sensitive files by uncommon processes. Could indicate potential attempt of stealing sensitive information.
Access To Browser Credential Files By Uncommon Applications
Detects file access requests to browser credential stores by uncommon processes. Could indicate potential attempt of credential stealing. Requires heavy baselining before usage
Access To Windows Outlook Mail Files By Uncommon Applications
Detects file access requests to Windows Outlook Mail by uncommon processes. Could indicate potential attempt of credential stealing. Requires heavy baselining before usage
Access To Sysvol Policies Share By Uncommon Process
Detects file access requests to the Windows Sysvol Policies Share by uncommon processes
Access To .Reg/.Hive Files By Uncommon Applications
Detects file access requests to files ending with either the ".hive"/".reg" extension, usually associated with Windows Registry backups.
Unattend.XML File Access Attempt
Detects attempts to access the "unattend.xml" file, where credentials might be stored. This file is used during the unattended windows install process.
File Creation Date Changed to Another Year
Detects when the file creation time is changed to a year before 2020. Attackers may change the file creation time of a backdoor to make it look like it was installed with the operating system. Note that many processes legitimately change the creation time of a file; it does not necessarily indicate malicious activity. In order to use this rule in production, it is recommended first baseline normal behavior in your environment and then tune the rule accordingly. Hunting Recommendation: Focus on files with creation times set to years significantly before the current date, especially those in user-writable directories. Correlate with process execution logs to identify the source of the modification and investigate any unsigned or suspicious binaries involved.
ADS Zone.Identifier Deleted
Detects the deletion of the "Zone.Identifier" ADS. Attackers can leverage this in order to bypass security restrictions that make use of the ADS such as Microsoft Office apps.
DMP/HDMP File Creation
Detects the creation of a file with the ".dmp"/".hdmp" extension. Often created by software during a crash. Memory dumps can sometimes contain sensitive information such as credentials. It's best to determine the source of the crash.
PFX File Creation
Detects the creation of PFX files (Personal Information Exchange format). PFX files contain private keys and certificates bundled together, making them valuable targets for attackers seeking to: - Exfiltrate digital certificates for impersonation or signing malicious code - Establish persistent access through certificate-based authentication - Bypass security controls that rely on certificate validation Analysts should investigate PFX file creation events by examining which process created the PFX file and its parent process chain, as well as unusual locations outside standard certificate stores or development environments.
Python Path Configuration File Creation - Windows
Detects creation of a Python path configuration file (.pth) in Python library folders, which can be maliciously abused for code execution and persistence. Modules referenced by these files are run at every Python startup (v3.5+), regardless of whether the module is imported by the calling script. Default paths are '\lib\site-packages\*.pth' (Windows) and '/lib/pythonX.Y/site-packages/*.pth' (Unix and macOS).
Scheduled Task Created - FileCreation
Detects the creation of a scheduled task via file creation.
Creation of an Executable by an Executable
Detects the creation of an executable by another executable.
VsCode Code Tunnel Execution File Indicator
Detects the creation of a file with the name "code_tunnel.json" which indicate execution and usage of VsCode tunneling utility. Attackers can abuse this functionality to establish a C2 channel
WDAC Policy File Creation In CodeIntegrity Folder
Attackers can craft a custom Windows Defender Application Control (WDAC) policy that blocks Endpoint Detection and Response (EDR) components while allowing their own malicious code. The policy is placed in the privileged Windows Code Integrity folder (C:\Windows\System32\CodeIntegrity\). Upon reboot, the policy prevents EDR drivers from loading, effectively bypassing security measures and may further enable undetected lateral movement within an Active Directory environment.
WebDAV Temporary Local File Creation
Detects the creation of WebDAV temporary files with potentially suspicious extensions
Non-DLL Extension File Renamed With DLL Extension
Detects rename operations of files with non-DLL extensions to files with a DLL extension. This is often performed by malware in order to avoid initial detections based on extensions.
Amsi.DLL Load By Uncommon Process
Detects loading of Amsi.dll by uncommon processes
BITS Client BitsProxy DLL Loaded By Uncommon Process
Detects an uncommon process loading the "BitsProxy.dll". This DLL is used when the BITS COM instance or API is used. This detection can be used to hunt for uncommon processes loading this DLL in your environment. Which may indicate potential suspicious activity occurring.
Dbghelp/Dbgcore DLL Loaded By Uncommon/Suspicious Process
Detects the load of dbghelp/dbgcore DLL by a potentially uncommon or potentially suspicious process. The Dbghelp and Dbgcore DLLs export functions that allow for the dump of process memory. Tools like ProcessHacker, Task Manager and some attacker tradecraft use the MiniDumpWriteDump API found in dbghelp.dll or dbgcore.dll. As an example, SilentTrynity C2 Framework has a module that leverages this API to dump the contents of Lsass.exe and transfer it over the network back to the attacker's machine. Keep in mind that many legitimate Windows processes and services might load the aforementioned DLLs for debugging or other related purposes. Investigate the CommandLine and the Image location of the process loading the DLL.
System Drawing DLL Load
Detects processes loading "System.Drawing.ni.dll". This could be an indicator of potential Screen Capture.
Task Scheduler DLL Loaded By Application Located In Potentially Suspicious Location
Detects the loading of the "taskschd.dll" module from a process that located in a potentially suspicious or uncommon directory. The loading of this DLL might indicate that the application have the capability to create a scheduled task via the "Schedule.Service" COM object. Investigation of the loading application and its behavior is required to determining if its malicious.
Microsoft Excel Add-In Loaded
Detects Microsoft Excel loading an Add-In (.xll) file
Microsoft Word Add-In Loaded
Detects Microsoft Word loading an Add-In (.wll) file which can be used by threat actors for initial access or persistence.
WerFaultSecure Loading DbgCore or DbgHelp - EDR-Freeze
Detects the loading of dbgcore.dll or dbghelp.dll by WerFaultSecure.exe, which has been observed in EDR-Freeze attacks to suspend processes and evade detection. However, this behavior has also been observed during normal software installations, so further investigation is required to confirm malicious activity. When threat hunting, look for this activity in conjunction with other suspicious processes starting, network connections, or file modifications that occur shortly after the DLL load. Pay special attention to timing - if other malicious activities occur during or immediately after this library loading, it may indicate EDR evasion attempts. Also correlate with any EDR/AV process suspension events or gaps in security monitoring during the timeframe.
WMI Module Loaded By Uncommon Process
Detects WMI modules being loaded by an uncommon process
Dfsvc.EXE Network Connection To Non-Local IPs
Detects network connections from "dfsvc.exe" used to handled ClickOnce applications to non-local IPs
Dfsvc.EXE Initiated Network Connection Over Uncommon Port
Detects an initiated network connection over uncommon ports from "dfsvc.exe". A utility used to handled ClickOnce applications.
Dllhost.EXE Initiated Network Connection To Non-Local IP Address
Detects Dllhost.EXE initiating a network connection to a non-local IP address. Aside from Microsoft own IP range that needs to be excluded. Network communication from Dllhost will depend entirely on the hosted DLL. An initial baseline is recommended before deployment.