mirror of
https://github.com/splunk/security_content
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pyth0n1c
103 lines
5.2 KiB
YAML
103 lines
5.2 KiB
YAML
name: Detect Webshell Exploit Behavior
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id: 22597426-6dbd-49bd-bcdc-4ec19857192f
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version: 8
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date: '2025-02-10'
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author: Steven Dick
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status: deprecated
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type: TTP
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description: The following analytic has been deprecated. The following analytic identifies
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the execution of suspicious processes typically associated with webshell activity
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on web servers. It detects when processes like `cmd.exe`, `powershell.exe`, or `bash.exe`
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are spawned by web server processes such as `w3wp.exe` or `nginx.exe`. This behavior
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is significant as it may indicate an adversary exploiting a web application vulnerability
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to install a webshell, providing persistent access and command execution capabilities.
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If confirmed malicious, this activity could allow attackers to maintain control
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over the compromised server, execute arbitrary commands, and potentially escalate
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privileges or exfiltrate sensitive data.
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data_source:
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- Sysmon EventID 1
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- Windows Event Log Security 4688
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- CrowdStrike ProcessRollup2
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search: '| tstats `security_content_summariesonly` count max(_time) as lastTime, min(_time)
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as firstTime from datamodel=Endpoint.Processes where (Processes.process_name IN
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("arp.exe","at.exe","bash.exe","bitsadmin.exe","certutil.exe","cmd.exe","cscript.exe",
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"dsget.exe","dsquery.exe","find.exe","findstr.exe","fsutil.exe","hostname.exe","ipconfig.exe","ksh.exe","nbstat.exe",
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"net.exe","net1.exe","netdom.exe","netsh.exe","netstat.exe","nltest.exe","nslookup.exe","ntdsutil.exe","pathping.exe",
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"ping.exe","powershell.exe","pwsh.exe","qprocess.exe","query.exe","qwinsta.exe","reg.exe","rundll32.exe","sc.exe",
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"scrcons.exe","schtasks.exe","sh.exe","systeminfo.exe","tasklist.exe","tracert.exe","ver.exe","vssadmin.exe",
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"wevtutil.exe","whoami.exe","wmic.exe","wscript.exe","wusa.exe","zsh.exe") AND Processes.parent_process_name
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IN ("w3wp.exe", "http*.exe", "nginx*.exe", "php*.exe", "php-cgi*.exe","tomcat*.exe"))
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by Processes.dest,Processes.user,Processes.parent_process,Processes.parent_process_name,Processes.process,Processes.process_name
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| `drop_dm_object_name("Processes")` | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`
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| `detect_webshell_exploit_behavior_filter`'
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how_to_implement: The detection is based on data that originates from Endpoint Detection
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and Response (EDR) agents. These agents are designed to provide security-related
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telemetry from the endpoints where the agent is installed. To implement this search,
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you must ingest logs that contain the process GUID, process name, and parent process.
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Additionally, you must ingest complete command-line executions. These logs must
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be processed using the appropriate Splunk Technology Add-ons that are specific to
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the EDR product. The logs must also be mapped to the `Processes` node of the `Endpoint`
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data model. Use the Splunk Common Information Model (CIM) to normalize the field
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names and speed up the data modeling process.
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known_false_positives: Legitimate OS functions called by vendor applications, baseline
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the environment and filter before enabling. Recommend throttle by dest/process_name
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references:
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- https://attack.mitre.org/techniques/T1505/003/
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- https://github.com/nsacyber/Mitigating-Web-Shells
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- https://www.hackingarticles.in/multiple-ways-to-exploit-tomcat-manager/
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drilldown_searches:
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- name: View the detection results for - "$user$" and "$dest$"
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search: '%original_detection_search% | search user = "$user$" dest = "$dest$"'
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earliest_offset: $info_min_time$
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latest_offset: $info_max_time$
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- name: View risk events for the last 7 days for - "$user$" and "$dest$"
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search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$user$",
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"$dest$") starthoursago=168 | stats count min(_time) as firstTime max(_time)
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as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk
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Message" values(analyticstories) as "Analytic Stories" values(annotations._all)
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as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics"
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by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`'
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earliest_offset: $info_min_time$
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latest_offset: $info_max_time$
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rba:
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message: Webshell Exploit Behavior - $parent_process_name$ spawned $process_name$
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on $dest$.
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risk_objects:
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- field: user
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type: user
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score: 80
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- field: dest
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type: system
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score: 80
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threat_objects:
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- field: process_name
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type: process_name
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tags:
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analytic_story:
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- ProxyNotShell
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- CISA AA22-257A
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- HAFNIUM Group
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- Citrix ShareFile RCE CVE-2023-24489
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- ProxyShell
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- Flax Typhoon
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- CISA AA22-264A
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- SysAid On-Prem Software CVE-2023-47246 Vulnerability
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- Compromised Windows Host
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- WS FTP Server Critical Vulnerabilities
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- BlackByte Ransomware
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asset_type: Endpoint
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mitre_attack_id:
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- T1505.003
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product:
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- Splunk Enterprise
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- Splunk Enterprise Security
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- Splunk Cloud
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security_domain: endpoint
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tests:
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- name: True Positive Test
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attack_data:
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- data:
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https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1505.003/generic_webshell_exploit/generic_webshell_exploit.log
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source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
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sourcetype: XmlWinEventLog
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