[New Rule] Web Server Discovery or Fuzzing Activity (#5337)

* [New Rule] Web Server Discovery or Fuzzing Activity

* Update reconnaissance_web_server_discovery_or_fuzzing_activity.toml

* Update reconnaissance_web_server_discovery_or_fuzzing_activity.toml

* Update reconnaissance_web_server_discovery_or_fuzzing_activity.toml

* Add case handling for URL normalization in rule

* Replace url.path with Esql_url_lower in TOML file

* Update reconnaissance_web_server_discovery_or_fuzzing_activity.toml

* ++

* Update reconnaissance_web_server_discovery_or_fuzzing_activity.toml

* Add manifest and schema updates

* Update reconnaissance_web_server_discovery_or_fuzzing_activity.toml

* ++

* Update fortigate schemas

* Revert "Update fortigate schemas"

This reverts commit b7c87b0.

* Revert "++"

This reverts commit 7f5d860.

* [New Rule] Web Server Discovery or Fuzzing Activity

* Update reconnaissance_web_server_discovery_or_fuzzing_activity.toml

* Update reconnaissance_web_server_discovery_or_fuzzing_activity.toml

* Update reconnaissance_web_server_discovery_or_fuzzing_activity.toml

* Add case handling for URL normalization in rule

* Replace url.path with Esql_url_lower in TOML file

* Update reconnaissance_web_server_discovery_or_fuzzing_activity.toml

* ++

* Update reconnaissance_web_server_discovery_or_fuzzing_activity.toml

* Add manifest and schema updates

* Update reconnaissance_web_server_discovery_or_fuzzing_activity.toml

* Added schema/manifest updates

* ++

* Update reconnaissance_web_server_discovery_or_fuzzing_activity.toml

* revert manifests / schemas to main

* adds nginx, iis, apache_tomcat, apache to integration manifests and schemas

* bumping patch version

---------

Co-authored-by: Shashank K S <[email protected]>
Co-authored-by: terrancedejesus <[email protected]>

(cherry picked from commit 167def0)

Author: Aegrah

detection_rules/etc/integration-manifests.json.gz

@@ -1,6 +1,6 @@
 [project]
 name = "detection_rules"
-version = "1.5.15"
+version = "1.5.16"
 description = "Detection Rules is the home for rules used by Elastic Security. This repository is used for the development, maintenance, testing, validation, and release of rules for Elastic Security’s Detection Engine."
 readme = "README.md"
 requires-python = ">=3.12"

detection_rules/etc/integration-schemas.json.gz

@@ -0,0 +1,89 @@
+[metadata]
+creation_date = "2025/11/19"
+integration = ["network_traffic", "nginx", "apache", "apache_tomcat", "iis"]
+maturity = "production"
+updated_date = "2025/11/19"
+
+[rule]
+author = ["Elastic"]
+description = """
+This rule detects potential web server discovery or fuzzing activity by identifying a high volume of HTTP GET requests resulting
+in 404 or 403 status codes from a single source IP address within a short timeframe. Such patterns may indicate that an attacker
+is attempting to discover hidden or unlinked resources on a web server, which can be a precursor to more targeted attacks.
+"""
+from = "now-9m"
+interval = "10m"
+language = "esql"
+license = "Elastic License v2"
+name = "Web Server Discovery or Fuzzing Activity"
+risk_score = 21
+rule_id = "8383a8d0-008b-47a5-94e5-496629dc3590"
+severity = "low"
+tags = [
+    "Domain: Web",
+    "Domain: Network",
+    "Use Case: Threat Detection",
+    "Tactic: Reconnaissance",
+    "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
+    http.request.method == "GET" and 
+    http.response.status_code in (404, 403)
+
+| eval Esql.url_text  = case(url.original is not null, url.original, url.full)
+| eval Esql.url_lower = to_lower(Esql.url_text)
+
+| keep
+    @timestamp,
+    event.dataset,
+    http.request.method,
+    http.response.status_code,
+    source.ip,
+    agent.id,
+    host.name,
+    Esql.url_lower
+| stats
+    Esql.event_count = count(),
+    Esql.url_lower_count_distinct = count_distinct(Esql.url_lower),
+    Esql.host_name_values = values(host.name),
+    Esql.agent_id_values = values(agent.id),
+    Esql.http_request_method_values = values(http.request.method),
+    Esql.http_response_status_code_values = values(http.response.status_code),
+    Esql.url_path_values = values(Esql.url_lower),
+    Esql.event_dataset_values = values(event.dataset)
+    by source.ip
+| where
+  Esql.event_count > 500 and Esql.url_lower_count_distinct > 250
+'''
+
+[[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/"