Sigma Rules
2,839 rules found
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.
HH.EXE Initiated HTTP Network Connection
Detects a network connection initiated by the "hh.exe" process to HTTP destination ports, which could indicate the execution/download of remotely hosted .chm files.
Msiexec.EXE Initiated Network Connection Over HTTP
Detects a network connection initiated by an "Msiexec.exe" process over port 80 or 443. Adversaries might abuse "msiexec.exe" to install and execute remotely hosted packages. Use this rule to hunt for potentially anomalous or suspicious communications.
Network Connection Initiated By PowerShell Process
Detects a network connection that was initiated from a PowerShell process. Often times malicious powershell scripts download additional payloads or communicate back to command and control channels via uncommon ports or IPs. Use this rule as a basis for hunting for anomalies.
Potentially Suspicious Azure Front Door Connection
Detects connections with Azure Front Door (known legitimate service that can be leveraged for C2) that fall outside of known benign behavioral baseline (not using common apps or common azurefd.net endpoints)
Network Connection Initiated From Users\Public Folder
Detects a network connection initiated from a process located in the "C:\Users\Public" folder. Attacker are known to drop their malicious payloads and malware in this directory as its writable by everyone. Use this rule to hunt for potential suspicious or uncommon activity in your environement.
PsExec Default Named Pipe
Detects PsExec service default pipe creation
Uncommon PowerShell Hosts
Detects alternate PowerShell hosts potentially bypassing detections looking for powershell.exe
bXOR Operator Usage In PowerShell Command Line - PowerShell Classic
Detects powershell execution with that make use of to the bxor (Bitwise XOR). Attackers might use as an alternative obfuscation method to Base64 encoded commands. Investigate the CommandLine and process tree to determine if the activity is malicious.
Local Firewall Rules Enumeration Via NetFirewallRule Cmdlet
Detects execution of "Get-NetFirewallRule" or "Show-NetFirewallRule" to enumerate the local firewall rules on a host.
Compress-Archive Cmdlet Execution
Detects PowerShell scripts that make use of the "Compress-Archive" cmdlet in order to compress folders and files. An adversary might compress data (e.g., sensitive documents) that is collected prior to exfiltration in order to make it portable and minimize the amount of data sent over the network.
Mail Forwarding/Redirecting Activity Via ExchangePowerShell Cmdlet
Detects email forwarding or redirecting activity via ExchangePowerShell Cmdlet
Inbox Rules Creation Or Update Activity Via ExchangePowerShell Cmdlet
Detects inbox rule creation or update via ExchangePowerShell cmdlet, 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.
Windows Mail App Mailbox Access Via PowerShell Script
Detects PowerShell scripts that try to access the default Windows MailApp MailBox. This indicates manipulation of or access to the stored emails of a user. E.g. this could be used by an attacker to exfiltrate or delete the content of the emails.
New Windows Firewall Rule Added Via New-NetFirewallRule Cmdlet - ScriptBlock
Detects when a powershell script contains calls to the "New-NetFirewallRule" cmdlet in order to add a new firewall rule with an "Allow" action.
SMB over QUIC Via PowerShell Script
Detects the mounting of Windows SMB shares over QUIC, which can be an unexpected event in some enterprise environments
Potential Registry Reconnaissance Via PowerShell Script
Detects PowerShell scripts with potential registry reconnaissance capabilities. Adversaries may interact with the Windows registry to gather information about the system credentials, configuration, and installed software.
Use Of Remove-Item to Delete File - ScriptBlock
PowerShell Remove-Item with -Path to delete a file or a folder with "-Recurse"
Potential Data Exfiltration Over SMTP Via Send-MailMessage Cmdlet
Detects the execution of a PowerShell script with a call to the "Send-MailMessage" cmdlet along with the "-Attachments" flag. This could be a potential sign of data exfiltration via Email. Adversaries may steal data by exfiltrating it over an un-encrypted network protocol other than that of the existing command and control channel. The data may also be sent to an alternate network location from the main command and control server.
Powershell Token Obfuscation - Powershell
Detects TOKEN OBFUSCATION technique from Invoke-Obfuscation in Powershell scripts. Use this rule as a threat-hunting baseline to find obfuscated scripts in your environment. Once tested and tuned, consider deploying a production detection rule based on this hunting rule.
WinAPI Library Calls Via PowerShell Scripts
Detects calls to WinAPI libraries from PowerShell scripts. Attackers can often leverage these APIs to avoid detection based on typical PowerShell function calls. Use this rule as a basis to hunt for interesting scripts.
WinAPI Function Calls Via PowerShell Scripts
Detects calls to WinAPI functions from PowerShell scripts. Attackers can often leverage these APIs to avoid detection based on typical PowerShell function calls. Use this rule as a basis to hunt for interesting scripts.
Potential Credential Dumping Attempt Via PowerShell
Detects a PowerShell process requesting access to "lsass.exe", which can be indicative of potential credential dumping attempts
LSASS Access From Program In Potentially Suspicious Folder
Detects process access to LSASS memory with suspicious access flags and from a potentially suspicious folder
Uncommon GrantedAccess Flags On LSASS
Detects process access to LSASS memory with uncommon access flags 0x410 and 0x01410
Potential Shellcode Injection
Detects potential shellcode injection as seen used by tools such as Metasploit's migrate and Empire's psinject.
Password Protected Compressed File Extraction Via 7Zip
Detects usage of 7zip utilities (7z.exe, 7za.exe and 7zr.exe) to extract password protected zip files.
Set Files as System Files Using Attrib.EXE
Detects the execution of "attrib" with the "+s" flag to mark files as system files
Potential BOINC Software Execution (UC-Berkeley Signature)
Detects the use of software that is related to the University of California, Berkeley via metadata information. This indicates it may be related to BOINC software and can be used maliciously if unauthorized.
CMD Shell Output Redirect
Detects the use of the redirection character ">" to redirect information on the command line. This technique is sometimes used by malicious actors in order to redirect the output of reconnaissance commands such as "hostname" and "dir" to files for future exfiltration.
Potential File Override/Append Via SET Command
Detects the use of the "SET" internal command of Cmd.EXE with the /p flag followed directly by an "=" sign. Attackers used this technique along with an append redirection operator ">>" in order to update the content of a file indirectly. Ex: cmd /c >> example.txt set /p="test data". This will append "test data" to contents of "example.txt". The typical use case of the "set /p=" command is to prompt the user for input.
Headless Process Launched Via Conhost.EXE
Detects the launch of a child process via "conhost.exe" with the "--headless" flag. The "--headless" flag hides the windows from the user upon execution.
Dynamic .NET Compilation Via Csc.EXE - Hunting
Detects execution of "csc.exe" to compile .NET code. Attackers often leverage this to compile code on the fly and use it in other stages.
File Download Via Curl.EXE
Detects file download using curl.exe
Curl.EXE Execution
Detects a curl process start on Windows, which could indicates a file download from a remote location or a simple web request to a remote server