EXPLORE DETECTIONS
Unusual Number of Kerberos Service Tickets Requested
The following analytic identifies an unusual number of Kerberos service ticket requests, potentially indicating a kerberoasting attack. It leverages Kerberos Event 4769 and calculates the standard deviation for each host, using the 3-sigma rule to detect anomalies. This activity is significant as kerberoasting allows adversaries to request service tickets and crack them offline, potentially gaining privileged access to the domain. If confirmed malicious, this could lead to unauthorized access to sensitive accounts and escalation of privileges within the Active Directory environment.
Unusual Number of Remote Endpoint Authentication Events
The following analytic identifies an unusual number of remote authentication attempts from a single source by leveraging Windows Event ID 4624, which logs successful account logons. It uses statistical analysis, specifically the 3-sigma rule, to detect deviations from normal behavior. This activity is significant for a SOC as it may indicate lateral movement, malware staging, or reconnaissance. If confirmed malicious, this behavior could allow an attacker to move laterally within the network, escalate privileges, or gather information for further attacks.
Unusually Long Command Line
The following analytic detects unusually long command lines, which may indicate malicious activity. It leverages data from Endpoint Detection and Response (EDR) agents, focusing on the length of command lines executed on hosts. This behavior is significant because attackers often use obfuscated or complex command lines to evade detection and execute malicious payloads. If confirmed malicious, this activity could lead to data theft, ransomware deployment, or further system compromise. Analysts should investigate the source and content of the command line, inspect relevant artifacts, and review concurrent processes to identify potential threats.
Unusually Long Content-Type Length
The following analytic identifies unusually long strings in the Content-Type HTTP header sent by the client to the server. It uses data from the Stream:HTTP source, specifically evaluating the length of the `cs_content_type` field. This activity is significant because excessively long Content-Type headers can indicate attempts to exploit vulnerabilities or evade detection mechanisms. If confirmed malicious, this behavior could allow attackers to execute code, manipulate data, or bypass security controls, potentially leading to unauthorized access or data breaches.
User Discovery With Env Vars PowerShell
The following analytic detects the execution of `powershell.exe` with command-line arguments that use PowerShell environment variables to identify the current logged user. It leverages data from Endpoint Detection and Response (EDR) agents, focusing on process names and command-line executions. This activity is significant as adversaries may use it for situational awareness and Active Directory discovery on compromised endpoints. If confirmed malicious, this behavior could allow attackers to gather critical user information, aiding in further exploitation and lateral movement within the network.
User Discovery With Env Vars PowerShell Script Block
The following analytic detects the use of PowerShell environment variables to identify the current logged user by leveraging PowerShell Script Block Logging (EventCode=4104). This method monitors script blocks containing `$env:UserName` or `[System.Environment]::UserName`. Identifying this activity is significant as adversaries and Red Teams may use it for situational awareness and Active Directory discovery on compromised endpoints. If confirmed malicious, this activity could allow attackers to gain insights into user context, aiding in further exploitation and lateral movement within the network.
USN Journal Deletion
The following analytic detects the deletion of the USN Journal using the fsutil.exe utility. It leverages data from Endpoint Detection and Response (EDR) agents, focusing on process execution logs that include command-line details. This activity is significant because the USN Journal maintains a log of all changes made to files on the disk, and its deletion can be an indicator of an attempt to cover tracks or hinder forensic investigations. If confirmed malicious, this action could allow an attacker to obscure their activities, making it difficult to trace file modifications and potentially compromising incident response efforts.
Vbscript Execution Using Wscript App
The following analytic detects the execution of VBScript using the wscript.exe application. It leverages data from Endpoint Detection and Response (EDR) agents, focusing on process and command-line telemetry. This activity is significant because wscript.exe is typically not used to execute VBScript, which is usually associated with cscript.exe. This deviation can indicate an attempt to evade traditional process monitoring and antivirus defenses. If confirmed malicious, this technique could allow attackers to execute arbitrary code, potentially leading to system compromise, data exfiltration, or further lateral movement within the network.
Verclsid CLSID Execution
The following analytic detects the potential abuse of the verclsid.exe utility to execute malicious files via generated CLSIDs. It leverages data from Endpoint Detection and Response (EDR) agents, focusing on specific command-line patterns associated with verclsid.exe. This activity is significant because verclsid.exe is a legitimate Windows application used to verify CLSID COM objects, and its misuse can indicate an attempt to bypass security controls. If confirmed malicious, this technique could allow an attacker to execute arbitrary code, potentially leading to system compromise or further malicious activities.
VMWare Aria Operations Exploit Attempt
The following analytic detects potential exploitation attempts against VMWare vRealize Network Insight, specifically targeting the CVE-2023-20887 vulnerability. It monitors web traffic for HTTP POST requests directed at the vulnerable endpoint "/saas./resttosaasservlet." This detection leverages web traffic data, focusing on specific URL patterns and HTTP methods. Identifying this behavior is crucial for a SOC as it indicates an active exploit attempt. If confirmed malicious, the attacker could execute arbitrary code, leading to unauthorized access, data theft, or further network compromise.
VMware Server Side Template Injection Hunt
The following analytic identifies potential server-side template injection attempts related to CVE-2022-22954. It detects suspicious URL patterns containing "deviceudid" and keywords like "java.lang.ProcessBuilder" or "freemarker.template.utility.ObjectConstructor" using web or proxy logs within the Web Datamodel. This activity is significant as it may indicate an attempt to exploit a known vulnerability in VMware, potentially leading to remote code execution. If confirmed malicious, attackers could gain unauthorized access, execute arbitrary code, and compromise the affected system, posing a severe security risk.
VMware Workspace ONE Freemarker Server-side Template Injection
The following analytic detects server-side template injection attempts related to CVE-2022-22954 in VMware Workspace ONE. It leverages web or proxy logs to identify HTTP GET requests to the endpoint catalog-portal/ui/oauth/verify with the freemarker.template.utility.Execute command. This activity is significant as it indicates potential exploitation attempts that could lead to remote code execution. If confirmed malicious, an attacker could execute arbitrary commands on the server, leading to full system compromise, data exfiltration, or further lateral movement within the network.
WBAdmin Delete System Backups
The following analytic detects the execution of wbadmin.exe with flags that delete backup files, specifically targeting catalog or system state backups. It leverages data from Endpoint Detection and Response (EDR) agents, focusing on process names and command-line arguments. This activity is significant because it is commonly used by ransomware to prevent recovery by deleting system backups. If confirmed malicious, this action could severely hinder recovery efforts, leading to prolonged downtime and potential data loss.
Wbemprox COM Object Execution
The following analytic detects a suspicious process loading a COM object from wbemprox.dll, fastprox.dll, or wbemcomn.dll. It leverages Sysmon EventCode 7 to identify instances where these DLLs are loaded by processes not typically associated with them, excluding known legitimate processes and directories. This activity is significant as it may indicate an attempt by threat actors to abuse COM objects for privilege escalation or evasion of detection mechanisms. If confirmed malicious, this could allow attackers to gain elevated privileges or maintain persistence within the environment, posing a significant security risk.
Web JSP Request via URL
The following analytic identifies URL requests associated with CVE-2022-22965 (Spring4Shell) exploitation attempts, specifically targeting webshell access on a remote webserver. It detects HTTP GET requests with URLs containing ".jsp?cmd=" or "j&cmd=" patterns. This activity is significant as it indicates potential webshell deployment, which can lead to unauthorized remote command execution. If confirmed malicious, attackers could gain control over the webserver, execute arbitrary commands, and potentially escalate privileges, leading to severe data breaches and system compromise.
Web or Application Server Spawning a Shell
The following analytic detects instances where Java, or Tomcat processes spawn a Linux shell, which may indicate exploitation attempts, such as those related to CVE-2021-44228 (Log4Shell). This detection leverages Endpoint Detection and Response (EDR) telemetry, focusing on process names and parent-child process relationships. This activity is significant as it can signify a compromised Java application, potentially leading to unauthorized shell access. If confirmed malicious, attackers could execute arbitrary commands, escalate privileges, or maintain persistent access, posing a severe threat to the environment.
Web Remote ShellServlet Access
The following analytic identifies attempts to access the Remote ShellServlet on a web server, specifically targeting Confluence servers vulnerable to CVE-2023-22518 and CVE-2023-22515. It leverages web data to detect URLs containing "*plugins/servlet/com.jsos.shell/*" with a status code of 200. This activity is significant as it is commonly associated with web shells and other malicious behaviors, potentially leading to unauthorized command execution. If confirmed malicious, attackers could gain remote code execution capabilities, compromising the server and potentially the entire network.
Web Servers Executing Suspicious Processes
The following analytic detects the execution of suspicious processes on systems identified as web servers. It leverages the Splunk data model "Endpoint.Processes" to search for specific process names such as "whoami", "ping", "iptables", "wget", "service", and "curl". This activity is significant because these processes are often used by attackers for reconnaissance, persistence, or data exfiltration. If confirmed malicious, this could lead to data theft, deployment of additional malware, or even ransomware attacks. Immediate investigation is required to determine the legitimacy of the activity and mitigate potential threats.
Web Spring Cloud Function FunctionRouter
The following analytic identifies HTTP POST requests to the Spring Cloud Function endpoint containing "functionRouter" in the URL. It leverages the Web data model to detect these requests based on specific fields such as http_method, url, and http_user_agent. This activity is significant because it targets CVE-2022-22963, a known vulnerability in Spring Cloud Function, which has multiple proof-of-concept exploits available. If confirmed malicious, this activity could allow attackers to execute arbitrary code, potentially leading to unauthorized access, data exfiltration, or further compromise of the affected system.
Web Spring4Shell HTTP Request Class Module
The following analytic detects HTTP requests containing payloads related to the Spring4Shell vulnerability (CVE-2022-22965). It leverages Splunk Stream HTTP data to inspect the HTTP request body and form data for specific fields such as "class.module.classLoader.resources.context.parent.pipeline.first". This activity is significant as it indicates an attempt to exploit a critical vulnerability in Spring Framework, potentially leading to remote code execution. If confirmed malicious, this could allow attackers to gain unauthorized access, execute arbitrary code, and compromise the affected system.
Wermgr Process Connecting To IP Check Web Services
The following analytic detects the wermgr.exe process attempting to connect to known IP check web services. It leverages Sysmon EventCode 22 to identify DNS queries made by wermgr.exe to specific IP check services. This activity is significant because wermgr.exe is typically used for Windows error reporting, and its connection to these services may indicate malicious code injection, often associated with malware like Trickbot. If confirmed malicious, this behavior could allow attackers to recon the infected machine's IP address, aiding in further exploitation and evasion tactics.
Wermgr Process Create Executable File
The following analytic detects the wermgr.exe process creating an executable file. It leverages Sysmon EventCode 11 to identify instances where wermgr.exe generates a .exe file. This behavior is unusual because wermgr.exe is typically associated with error reporting, not file creation. Such activity is significant as it may indicate TrickBot malware, which injects code into wermgr.exe to execute malicious actions like downloading additional payloads. If confirmed malicious, this could lead to further malware infections, data exfiltration, or system compromise.
Wermgr Process Spawned CMD Or Powershell Process
The following analytic detects the spawning of cmd or PowerShell processes by the wermgr.exe process. It leverages data from Endpoint Detection and Response (EDR) agents, focusing on process telemetry, including parent-child process relationships and command-line executions. This behavior is significant as it is commonly associated with code injection techniques used by malware like TrickBot to execute shellcode or malicious DLL modules. If confirmed malicious, this activity could allow attackers to execute arbitrary code, escalate privileges, or maintain persistence within the environment, posing a severe threat to system security.
Windows Abused Web Services
The following analytic detects a suspicious process making DNS queries to known, abused web services such as text-paste sites, VoIP, secure tunneling, instant messaging, and digital distribution platforms. This detection leverages Sysmon logs with Event ID 22, focusing on specific query names. This activity is significant as it may indicate an adversary attempting to download malicious files, a common initial access technique. If confirmed malicious, this could lead to unauthorized code execution, data exfiltration, or further compromise of the target host.