[metadata] creation_date = "2020/02/18" ecs_version = ["1.4.0"] maturity = "production" updated_date = "2020/02/18" [rule] author = ["Elastic"] description = "A request to a web application server contained no identifying user agent string." false_positives = [ """ Some normal applications and scripts may contain no user agent. Most legitimate web requests from the Internet contain a user agent string. Requests from web browsers almost always contain a user agent string. If the source is unexpected, the user unauthorized, or the request unusual, these may indicate suspicious or malicious activity. """, ] index = ["apm-*-transaction*"] language = "kuery" license = "Elastic License" name = "Web Application Suspicious Activity: No User Agent" references = ["https://en.wikipedia.org/wiki/User_agent"] risk_score = 47 rule_id = "43303fd4-4839-4e48-b2b2-803ab060758d" severity = "medium" tags = ["APM", "Elastic"] type = "query" query = ''' url.path:* ''' [[rule.filters]] [rule.filters."$state"] store = "appState" [rule.filters.exists] field = "user_agent.original" [rule.filters.meta] disabled = false indexRefName = "kibanaSavedObjectMeta.searchSourceJSON.filter[0].meta.index" key = "user_agent.original" negate = true type = "exists" value = "exists"