Web Remote ShellServlet Access

name: Web Remote ShellServlet Access
id: c2a332c3-24a2-4e24-9455-0e80332e6746
version: 9
date: '2026-03-10'
author: Michael Haag, Splunk
status: production
type: TTP
data_source:
    - Nginx Access
description: 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.
search: |-
    | tstats count min(_time) as firstTime max(_time) as lastTime FROM datamodel=Web
      WHERE Web.url IN ("*plugins/servlet/com.jsos.shell/*") Web.status=200
      BY Web.http_user_agent, Web.status Web.http_method,
         Web.url, Web.url_length, Web.src,
         Web.dest, sourcetype
    | `drop_dm_object_name("Web")`
    | `security_content_ctime(firstTime)`
    | `security_content_ctime(lastTime)`
    | `web_remote_shellservlet_access_filter`
how_to_implement: This analytic necessitates the collection of web data, which can be achieved through Splunk Stream or by utilizing the Splunk Add-on for Apache Web Server. No additional configuration is required for this analytic.
known_false_positives: False positives may occur depending on the web server's configuration. If the web server is intentionally configured to utilize the Remote ShellServlet, then the detections by this analytic would not be considered true positives.
references:
    - http://www.servletsuite.com/servlets/shell.htm
drilldown_searches:
    - name: View the detection results for - "$dest$"
      search: '%original_detection_search% | search  dest = "$dest$"'
      earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
    - name: View risk events for the last 7 days for - "$dest$"
      search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$dest$") starthoursago=168  | stats count min(_time) as firstTime max(_time) as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories) as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`'
      earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
rba:
    message: An attempt to access the Remote ShellServlet on a web server was detected. The source IP is $src$ and the destination hostname is $dest$.
    risk_objects:
        - field: dest
          type: system
          score: 50
    threat_objects:
        - field: src
          type: ip_address
tags:
    analytic_story:
        - CVE-2023-22515 Privilege Escalation Vulnerability Confluence Data Center and Server
        - GhostRedirector IIS Module and Rungan Backdoor
    asset_type: Web Server
    atomic_guid: []
    mitre_attack_id:
        - T1190
    product:
        - Splunk Enterprise
        - Splunk Enterprise Security
        - Splunk Cloud
    security_domain: network
tests:
    - name: True Positive Test
      attack_data:
        - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1190/confluence/nginx_shellservlet.log
          source: /var/log/nginx/access.log
          sourcetype: nginx:plus:kv