[New Rule] Web Server Potential Command Injection Request (#5341)

* [New Rule] Web Server Potential Command Injection Request

* Update variable names to use consistent casing

* Add 'Domain: Network' tag to command injection rule

* Update persistence_web_server_potential_command_injection.toml

* adding missing tags

* Update rules/cross-platform/persistence_web_server_potential_command_injection.toml

Co-authored-by: shashank-elastic <[email protected]>

* Update rules/cross-platform/persistence_web_server_potential_command_injection.toml

Co-authored-by: shashank-elastic <[email protected]>

---------

Co-authored-by: Terrance DeJesus <[email protected]>
Co-authored-by: terrancedejesus <[email protected]>
Co-authored-by: shashank-elastic <[email protected]>

(cherry picked from commit 94ff4b0)

Author: Aegrah

rules/cross-platform/persistence_web_server_potential_command_injection.toml

@@ -0,0 +1,196 @@
+[metadata]
+creation_date = "2025/11/19"
+integration = ["nginx", "apache", "apache_tomcat", "iis", "network_traffic"]
+maturity = "production"
+updated_date = "2025/11/19"
+
+[rule]
+author = ["Elastic"]
+description = """
+This rule detects potential command injection attempts via web server requests by identifying URLs that contain
+suspicious patterns commonly associated with command execution payloads. Attackers may exploit vulnerabilities in web
+applications to inject and execute arbitrary commands on the server, often using interpreters like Python, Perl, Ruby,
+PHP, or shell commands. By monitoring for these indicators in web traffic, security teams can identify and respond to
+potential threats early.
+"""
+from = "now-9m"
+interval = "10m"
+language = "esql"
+license = "Elastic License v2"
+name = "Web Server Potential Command Injection Request"
+risk_score = 21
+rule_id = "f3ac6734-7e52-4a0d-90b7-6847bf4308f2"
+severity = "low"
+tags = [
+    "Domain: Web",
+    "Domain: Network",
+    "Use Case: Threat Detection",
+    "Tactic: Reconnaissance",
+    "Tactic: Persistence",
+    "Tactic: Execution",
+    "Tactic: Credential Access",
+    "Tactic: Command and Control",
+    "Data Source: Network Packet Capture",
+    "Data Source: Nginx",
+    "Data Source: Apache",
+    "Data Source: Apache Tomcat",
+    "Data Source: IIS",
+]
+timestamp_override = "event.ingested"
+type = "esql"
+query = '''
+from logs-network_traffic.http-*, logs-network_traffic.tls-*, logs-nginx.access-*, logs-apache.access-*, logs-apache_tomcat.access-*, logs-iis.access-*
+| where
+    (url.original is not null or url.full is not null) and
+    // Limit to 200 response code to reduce noise
+    http.response.status_code == 200
+
+| eval Esql.url_lower  = case(url.original is not null, url.original, url.full)
+| eval Esql.url_lower = to_lower(Esql.url_lower)
+
+| eval Esql.contains_interpreter = case(Esql.url_lower like "*python* -c*" or Esql.url_lower like "*perl* -e*" or Esql.url_lower like "*ruby* -e*" or Esql.url_lower like "*ruby* -rsocket*" or Esql.url_lower like "*lua* -e*" or Esql.url_lower like "*php* -r*" or Esql.url_lower like "*node* -e*", 1, 0)
+| eval Esql.contains_shell = case(Esql.url_lower like "*/bin/bash*" or Esql.url_lower like "*bash*-c*" or Esql.url_lower like "*/bin/sh*" or Esql.url_lower rlike "*sh.{1,2}-c*", 1, 0)
+| eval Esql.contains_nc = case(Esql.url_lower like "*netcat*" or Esql.url_lower like "*ncat*" or Esql.url_lower rlike """.*nc.{1,2}[0-9]{1,3}(\.[0-9]{1,3}){3}.{1,2}[0-9]{1,5}.*""" or Esql.url_lower like "*nc.openbsd*" or Esql.url_lower like "*nc.traditional*" or Esql.url_lower like "*socat*", 1, 0)
+| eval Esql.contains_devtcp = case(Esql.url_lower like "*/dev/tcp/*" or Esql.url_lower like "*/dev/udp/*", 1, 0)
+| eval Esql.contains_helpers = case((Esql.url_lower like "*/bin/*" or Esql.url_lower like "*/usr/bin/*") and (Esql.url_lower like "*mkfifo*" or Esql.url_lower like "*nohup*" or Esql.url_lower like "*setsid*" or Esql.url_lower like "*busybox*"), 1, 0)
+| eval Esql.contains_sus_cli = case(Esql.url_lower like "*import*pty*spawn*" or Esql.url_lower like "*import*subprocess*call*" or Esql.url_lower like "*tcpsocket.new*" or Esql.url_lower like "*tcpsocket.open*" or Esql.url_lower like "*io.popen*" or Esql.url_lower like "*os.execute*" or Esql.url_lower like "*fsockopen*", 1, 0)
+| eval Esql.contains_privileges = case(Esql.url_lower like "*chmod*+x", 1, 0)
+| eval Esql.contains_downloader = case(Esql.url_lower like "*curl *" or Esql.url_lower like "*wget *" , 1, 0)
+| eval Esql.contains_file_read_keywords = case(Esql.url_lower like "*/etc/shadow*" or Esql.url_lower like "*/etc/passwd*" or Esql.url_lower like "*/root/.ssh/*" or Esql.url_lower like "*/home/*/.ssh/*" or Esql.url_lower like "*~/.ssh/*" or Esql.url_lower like "*/proc/self/environ*", 1, 0)
+| eval Esql.contains_base64_cmd = case(Esql.url_lower like "*base64*-d*" or Esql.url_lower like "*echo*|*base64*", 1, 0)
+| eval Esql.contains_suspicious_path = case(Esql.url_lower like "*/tmp/*" or Esql.url_lower like "*/var/tmp/*" or Esql.url_lower like "*/dev/shm/*" or Esql.url_lower like "*/root/*" or Esql.url_lower like "*/home/*/*" or Esql.url_lower like "*/var/www/*" or Esql.url_lower like "*/etc/cron.*/*", 1, 0)
+
+| eval Esql.any_payload_keyword = case(
+    Esql.contains_interpreter == 1 or Esql.contains_shell == 1 or Esql.contains_nc == 1 or Esql.contains_devtcp == 1 or
+    Esql.contains_helpers == 1 or Esql.contains_sus_cli == 1 or Esql.contains_privileges == 1 or Esql.contains_downloader == 1 or
+    Esql.contains_file_read_keywords == 1 or Esql.contains_base64_cmd == 1 or Esql.contains_suspicious_path == 1, 1, 0)
+
+| keep
+    @timestamp,
+    Esql.url_lower,
+    Esql.any_payload_keyword,
+    Esql.contains_interpreter,
+    Esql.contains_shell,
+    Esql.contains_nc,
+    Esql.contains_devtcp,
+    Esql.contains_helpers,
+    Esql.contains_sus_cli,
+    Esql.contains_privileges,
+    Esql.contains_downloader,
+    Esql.contains_file_read_keywords,
+    Esql.contains_base64_cmd,
+    Esql.contains_suspicious_path,
+    source.ip,
+    destination.ip,
+    agent.id,
+    http.request.method,
+    http.response.status_code,
+    user_agent.original,
+    host.name,
+    event.dataset
+
+| stats
+    Esql.event_count = count(),
+    Esql.url_path_count_distinct = count_distinct(Esql.url_lower),
+
+    // General fields
+
+    Esql.host_name_values = values(host.name),
+    Esql.agent_id_values = values(agent.id),
+    Esql.url_path_values = values(Esql.url_lower),
+    Esql.http.response.status_code_values = values(http.response.status_code),
+    Esql.user_agent_original_values = values(user_agent.original),
+    Esql.event_dataset_values = values(event.dataset),
+
+    // Rule Specific fields
+    Esql.any_payload_keyword_max = max(Esql.any_payload_keyword),
+    Esql.contains_interpreter_values = values(Esql.contains_interpreter),
+    Esql.contains_shell_values = values(Esql.contains_shell),
+    Esql.contains_nc_values = values(Esql.contains_nc),
+    Esql.contains_devtcp_values = values(Esql.contains_devtcp),
+    Esql.contains_helpers_values = values(Esql.contains_helpers),
+    Esql.contains_sus_cli_values = values(Esql.contains_sus_cli),
+    Esql.contains_privileges_values = values(Esql.contains_privileges),
+    Esql.contains_downloader_values = values(Esql.contains_downloader),
+    Esql.contains_file_read_keywords_values = values(Esql.contains_file_read_keywords),
+    Esql.contains_base64_cmd_values = values(Esql.contains_base64_cmd),
+    Esql.contains_suspicious_path_values = values(Esql.contains_suspicious_path)
+
+    by source.ip, agent.id
+
+| where
+    // Filter for potential command injection attempts with low event counts to reduce false positives
+    Esql.any_payload_keyword_max == 1 and Esql.event_count < 5
+'''
+
+[[rule.threat]]
+framework = "MITRE ATT&CK"
+
+[[rule.threat.technique]]
+id = "T1505"
+name = "Server Software Component"
+reference = "https://attack.mitre.org/techniques/T1505/"
+
+[[rule.threat.technique.subtechnique]]
+id = "T1505.003"
+name = "Web Shell"
+reference = "https://attack.mitre.org/techniques/T1505/003/"
+
+[rule.threat.tactic]
+id = "TA0003"
+name = "Persistence"
+reference = "https://attack.mitre.org/tactics/TA0003/"
+
+[[rule.threat]]
+framework = "MITRE ATT&CK"
+
+[[rule.threat.technique]]
+id = "T1059"
+name = "Command and Scripting Interpreter"
+reference = "https://attack.mitre.org/techniques/T1059/"
+
+[[rule.threat.technique.subtechnique]]
+id = "T1059.004"
+name = "Unix Shell"
+reference = "https://attack.mitre.org/techniques/T1059/004/"
+
+[rule.threat.tactic]
+id = "TA0002"
+name = "Execution"
+reference = "https://attack.mitre.org/tactics/TA0002/"
+
+[[rule.threat]]
+framework = "MITRE ATT&CK"
+
+[[rule.threat.technique]]
+id = "T1071"
+name = "Application Layer Protocol"
+reference = "https://attack.mitre.org/techniques/T1071/"
+
+[rule.threat.tactic]
+id = "TA0011"
+name = "Command and Control"
+reference = "https://attack.mitre.org/tactics/TA0011/"
+
+[[rule.threat]]
+framework = "MITRE ATT&CK"
+
+[[rule.threat.technique]]
+id = "T1595"
+name = "Active Scanning"
+reference = "https://attack.mitre.org/techniques/T1595/"
+
+[[rule.threat.technique.subtechnique]]
+id = "T1595.002"
+name = "Vulnerability Scanning"
+reference = "https://attack.mitre.org/techniques/T1595/002/"
+
+[[rule.threat.technique.subtechnique]]
+id = "T1595.003"
+name = "Wordlist Scanning"
+reference = "https://attack.mitre.org/techniques/T1595/003/"
+
+[rule.threat.tactic]
+id = "TA0043"
+name = "Reconnaissance"
+reference = "https://attack.mitre.org/tactics/TA0043/"