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detections/endpoint/detect_webshell_exploit_behavior.yml

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+name: Detect Webshell Exploit Behavior
+id: 22597426-6dbd-49bd-bcdc-4ec19857192f
+version: 1
+date: '2023-04-04'
+author: Steven Dick
+type: TTP
+datamodel:
+- Endpoint
+description: This search is used to detect the abuse of web applications by adversaries. 
+Adversaries may install a backdoor or script onto web servers by exploiting known 
+vulnerabilities or misconfigruations. Web shells are used to establish persistent access 
+to systems and provide a set of executable functions or a command-line interface on the 
+system hosting the Web server.
+search: '| tstats `summariesonly` count max(_time) as lastTime, min(_time) as firstTime from datamodel=Endpoint.Processes 
+where (Processes.process_name IN ("arp.exe","at.exe","bash.exe","bitsadmin.exe","certutil.exe","cmd.exe","cscript.exe", 
+"dsget.exe","dsquery.exe","find.exe","findstr.exe","fsutil.exe","hostname.exe","ipconfig.exe","ksh.exe","nbstat.exe",
+"net.exe","net1.exe","netdom.exe","netsh.exe","netstat.exe","nltest.exe","nslookup.exe","ntdsutil.exe","pathping.exe",
+"ping.exe","powershell.exe","pwsh.exe","qprocess.exe","query.exe","qwinsta.exe","reg.exe","rundll32.exe","sc.exe",
+"scrcons.exe","schtasks.exe","sh.exe","systeminfo.exe","tasklist.exe","tracert.exe","ver.exe","vssadmin.exe",
+"wevtutil.exe","whoami.exe","wmic.exe","wscript.exe","wusa.exe","zsh.exe") 
+AND Processes.parent_process_name IN ("w3wp.exe", "http*.exe", "nginx*.exe", "php*.exe", "php-cgi*.exe","tomcat*.exe")) 
+by Processes.dest,Processes.user,Processes.parent_process,Processes.parent_process_name,Processes.process,Processes.process_name
+| `drop_dm_object_name("Processes")`
+| `security_content_ctime(firstTime)` 
+| `security_content_ctime(lastTime)`
+| `detect_webshell_exploit_behavior`'
+how_to_implement: To successfully implement this search you need to be ingesting information
+  on process that includes the full command line of the process being launched on
+  your endpoints into the `Endpoint` datamodel in the `Processes` node. In addition,
+  confirm the latest CIM App 4.20 or higher is installed and the latest TA for the
+  endpoint product.
+known_false_positives: Legitimate OS funcations called by vendor applications, baseline the enviroment and filter before enabling.
+Recommend throttle by dest/process_name
+references:
+- https://attack.mitre.org/techniques/T1505/003/
+- https://github.com/nsacyber/Mitigating-Web-Shells
+- https://www.hackingarticles.in/multiple-ways-to-exploit-tomcat-manager/
+tags:
+  analytic_story:
+  confidence: 80
+  context:
+  - Source:Endpoint
+  - Stage:Persistence
+  dataset:
+  - https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1505.003/generic_webshell_exploit/generic_webshell_exploit.log
+  impact: 100
+  kill_chain_phases:
+  - Persistence
+  message: Webshell Exploit Behavior - $parent_process_name$ spawned $process_name$ on $dest$.
+  mitre_attack_id:
+  - T1505
+  - T1505.003
+  observable:
+  - name: user
+    type: User
+    role:
+    - Victim
+  - name: dest
+    type: Endpoint
+    role:
+    - Victim
+  - name: process_name
+    type: Process
+    role:
+    - Attacker
+  product:
+  - Splunk Enterprise
+  - Splunk Enterprise Security
+  - Splunk Cloud
+  required_fields:
+  - _time
+  - Processes.dest
+  - Processes.user
+  - Processes.parent_process
+  - Processes.parent_process_name
+  - Processes.process
+  - Processes.process_name
+  risk_score: 80
+  security_domain: endpoint
+  supported_tas:
+  - Splunk_TA_microsoft_sysmon
+  asset_type: Endpoint