NGINX - Known malicious user agent

Status: available
Severity: high
Time window: 10m
Source: github.com/Azure/Azure-Sentinel

'Detects known malicious user agents'

MITRE ATT&CK coverage

Tactic	Techniques
Initial Access	`T1133` External Remote Services, `T1190` Exploit Public-Facing Application

Rule body kusto

id: a10c6551-bbf2-492c-aa8a-fe6efd8c9cc1
name: NGINX - Known malicious user agent
description: |
  'Detects known malicious user agents'
severity: High
status: Available
requiredDataConnectors:
  - connectorId: CustomLogsAma
    dataTypes:
      - NGINX_CL
queryFrequency: 10m
queryPeriod: 10m
triggerOperator: gt
triggerThreshold: 0
tactics:
  - InitialAccess
relevantTechniques:
  - T1190
  - T1133
query: |
  let mal_ua_list = dynamic(['Nikto', '(hydra)', '.nasl', 'absinthe', 'advanced email extractor', 'arachni/', 'autogetcontent', 'bilbo', 'BFAC', 'brutus', 'brutus/aet', 'bsqlbf', 'cgichk', 'cisco-torch', 'commix', 'core-project/1.0', 'crimscanner/', 'datacha0s', 'dirbuster', 'domino hunter', 'dotdotpwn', 'email extractor', 'fhscan core 1.', 'floodgate', 'get-minimal', 'gootkit auto-rooter scanner', 'grabber', 'grendel-scan', 'havij', 'inspath', 'internet ninja', 'jaascois', 'zmeu', 'masscan', 'metis', 'morfeus', 'mysqloit', 'n-stealth', 'nessus', 'netsparker', 'nmap nse', 'nmap scripting engine', 'nmap-nse', 'nsauditor', 'openvas', 'pangolin', 'paros', 'pmafind', 'prog.customcrawler', 'qualys was', 's.t.a.l.k.e.r.', 'security scan', 'springenwerk', 'sql power injector', 'sqlmap', 'sqlninja', 'teh forest lobster', 'this is an exploit', 'toata dragostea', 'toata dragostea mea pentru diavola', 'uil2pn', 'user-agent:', 'vega/', 'voideye', 'w3af.sf.net', 'w3af.sourceforge.net', 'w3af.org', 'webbandit', 'webinspect', 'webshag', 'webtrends security analyzer', 'webvulnscan', 'whatweb', 'whcc/', 'wordpress hash grabber', 'xmlrpc exploit', 'WPScan', 'XSpider', 'SF/', 'FooBar/42', 'ScanAlert', 'Webscanner', 'Webster', 'fantomCrew', 'fantomBrowser', 'visvo', 'magereport', 'ltx71', 'websiteprotection', 'BigCliqueBOT', '(BOT for JCE)']);
  NGINXHTTPServer
  | where HttpUserAgentOriginal has_any (mal_ua_list)
  | extend IPCustomEntity = SrcIpAddr, MalwareCustomEntity = HttpUserAgentOriginal
entityMappings:
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: IPCustomEntity
  - entityType: Malware
    fieldMappings:
      - identifier: Name
        columnName: MalwareCustomEntity
version: 1.0.3
kind: Scheduled

Stages and Predicates

Let binding: `mal_ua_list`

let mal_ua_list = dynamic(['Nikto', '(hydra)', '.nasl', 'absinthe', 'advanced email extractor', 'arachni/', 'autogetcontent', 'bilbo', 'BFAC', 'brutus', 'brutus/aet', 'bsqlbf', 'cgichk', 'cisco-torch', 'commix', 'core-project/1.0', 'crimscanner/', 'datacha0s', 'dirbuster', 'domino hunter', 'dotdotpwn', 'email extractor', 'fhscan core 1.', 'floodgate', 'get-minimal', 'gootkit auto-rooter scanner', 'grabber', 'grendel-scan', 'havij', 'inspath', 'internet ninja', 'jaascois', 'zmeu', 'masscan', 'metis', 'morfeus', 'mysqloit', 'n-stealth', 'nessus', 'netsparker', 'nmap nse', 'nmap scripting engine', 'nmap-nse', 'nsauditor', 'openvas', 'pangolin', 'paros', 'pmafind', 'prog.customcrawler', 'qualys was', 's.t.a.l.k.e.r.', 'security scan', 'springenwerk', 'sql power injector', 'sqlmap', 'sqlninja', 'teh forest lobster', 'this is an exploit', 'toata dragostea', 'toata dragostea mea pentru diavola', 'uil2pn', 'user-agent:', 'vega/', 'voideye', 'w3af.sf.net', 'w3af.sourceforge.net', 'w3af.org', 'webbandit', 'webinspect', 'webshag', 'webtrends security analyzer', 'webvulnscan', 'whatweb', 'whcc/', 'wordpress hash grabber', 'xmlrpc exploit', 'WPScan', 'XSpider', 'SF/', 'FooBar/42', 'ScanAlert', 'Webscanner', 'Webster', 'fantomCrew', 'fantomBrowser', 'visvo', 'magereport', 'ltx71', 'websiteprotection', 'BigCliqueBOT', '(BOT for JCE)']);

Stage 1: `source`

NGINXHTTPServer

Stage 2: `where`

| where HttpUserAgentOriginal has_any (mal_ua_list)

References mal_ua_list (defined above).

Stage 3: `extend`

| extend IPCustomEntity = SrcIpAddr, MalwareCustomEntity = HttpUserAgentOriginal

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

Field	Kind	Values
`HttpUserAgentOriginal`	match	`(BOT for JCE)` `(hydra)` `.nasl` `BFAC` `BigCliqueBOT` `FooBar/42` `Nikto` `SF/` `ScanAlert` `WPScan` `Webscanner` `Webster` `XSpider` `absinthe` `advanced email extractor` `arachni/` `autogetcontent` `bilbo` `brutus` `brutus/aet` `bsqlbf` `cgichk` `cisco-torch` `commix` `core-project/1.0` `crimscanner/` `datacha0s` `dirbuster` `domino hunter` `dotdotpwn` `email extractor` `fantomBrowser` `fantomCrew` `fhscan core 1.` `floodgate` `get-minimal` `gootkit auto-rooter scanner` `grabber` `grendel-scan` `havij` `inspath` `internet ninja` `jaascois` `ltx71` `magereport` `masscan` `metis` `morfeus` `mysqloit` `n-stealth` `nessus` `netsparker` `nmap nse` `nmap scripting engine` `nmap-nse` `nsauditor` `openvas` `pangolin` `paros` `pmafind` `prog.customcrawler` `qualys was` `s.t.a.l.k.e.r.` `security scan` `springenwerk` `sql power injector` `sqlmap` `sqlninja` `teh forest lobster` `this is an exploit` `toata dragostea` `toata dragostea mea pentru diavola` `uil2pn` `user-agent:` `vega/` `visvo` `voideye` `w3af.org` `w3af.sf.net` `w3af.sourceforge.net` `webbandit` `webinspect` `webshag` `websiteprotection` `webtrends security analyzer` `webvulnscan` `whatweb` `whcc/` `wordpress hash grabber` `xmlrpc exploit` `zmeu`

Output fields

Fields the rule emits when it matches. Chronicle authors list these in the outcome block; they appear on the detection and $risk_score drives alerting. Sentinel / Defender XDR rules build them up through project / summarize / extend stages. Sentinel maps these into alert fields via entityMappings and customDetails; Defender XDR custom detections surface them as alert fields directly.

Field	Source
`IPCustomEntity`	`extend`
`MalwareCustomEntity`	`extend`

`j` / `k`	Scroll down / up
`d` / `u`	Half-page down / up
`gg` / `G`	Top / bottom
`h` / `l`	History back / forward
`f`	Follow link (`Shift` = new tab)
`/`	Focus search
`?`	Toggle this help
`↑` / `↓`	Navigate search results
`Enter`	Open highlighted result
`Esc`	Close results / dialog

`type:`	`events` / `rules` / `providers`
`vendor:`	`sigma` / `elastic` / `splunk` / `kusto` / `chronicle` (vendor name alone also works: `sigma:`, `kql:`, `secops:`…)
`tactic:`	TA-id, slug, or name: `credential_access`, `TA0006`
`technique:`	technique or sub-technique ID: `T1003`, `T1003.001` (alias `tech:`)
`severity:`	`critical` / `high` / `medium` / `low` / `informational` (alias `sev:`)
`risk_score`	Numeric comparison on the Elastic risk score (0 to 100): `risk_score>50`, `risk_score<=20`, `risk_score=99` (alias `risk`; Elastic rules only)
`stages:`	Rules with exactly N pipeline stages
`correlation:`	`single_event` / `sequence` / `alternatives` / `alternatives_cross_log` / `all_required` / `correlated`
`with:`	Co-occurrence event-id; stacks (`with:4624 with:4769`) to require all, while a comma list in one occurrence (`with:4624,4769`) is an either-or group. Implies multi-event
`like:`	Structural neighbors of a rule slug (equivalents + subsumption stricter / broader): `like:comsvcs_lsass_memory_dump-splunk-sysmon`
`groupby:`	Entity-grouping substring match against `group_by_keys`: `groupby:user`, `groupby:host`
`uses:`	Rules whose predicate tree touches the field (any kind, any value): `uses:CommandLine`
`excludes:`	Rules with top-level `not()` clauses on the field (FP whitelists): `excludes:ParentImage`
`field:` / `value:`	Predicate search; narrows rule cards to those with a matching leaf and drives the indicator tier. Unquoted = substring, wildcards allowed (`value:mimikatz`)
`indicator:`	Shorthand for `field:F value:V`: `indicator:Image=*\powershell.exe`
`kind:`	Filter by predicate kind. Narrows rule cards to those carrying a matching predicate leaf (`vendor:elastic kind:cidr_match`) and drives the indicator tier: `contains` / `starts_with` / `ends_with` / `regex` / `cidr` / `eq` / `in` … (operator aliases `op:`/`match:`)
`has:` / `no:`	`sample`, `field`, `notes`, `refs`, `trace`, `thirdparty`, `rule`, `pattern`, `timewindow`, `threshold`, `newterms`, `sigma`/`elastic`/`splunk`/`kusto`/`chronicle`
`-op:val`	Exclude matches; works on most operators but not `type:`/`like:`/`has:`/`no:` (use `no:<flag>` to exclude a rule flag): `tactic:execution -vendor:splunk`. Standalone `-kind:`/`-field:`/`-value:` drop every rule carrying a matching predicate leaf (`type:rules -kind:is_null`)
`field:"…"` / `value:"…"`	Quoted value = anchored exact match (also allows spaces): `value:"net user"`
`a,b`	Comma = OR inside one operator (`vendor:sigma,elastic`, `severity:high,critical`); repeating a facet merges the same way. `field:`/`value:` never split (literal commas)
`vendors:` / `stage:`	Singular and plural spellings fold to the canonical operator and value: `tactics:` = `tactic:`, `type:event` = `type:events`, `correlation:sequences` = `correlation:sequence`, `has:thresholds` = `has:threshold`
`"quoted phrase"`	Exact-match a multi-word phrase (free text)

NGINX - Known malicious user agent

MITRE ATT&CK coverage

Rule body kusto

Stages and Predicates

Let binding: `mal_ua_list`

Stage 1: `source`

Stage 2: `where`

Stage 3: `extend`

Indicators

Output fields

Keyboard shortcuts

Search operators

NGINX - Known malicious user agent

MITRE ATT&CK coverage

Rule body kusto

Stages and Predicates

Let binding: mal_ua_list

Stage 1: source

Stage 2: where

Stage 3: extend

Indicators

Output fields

Let binding: `mal_ua_list`

Stage 1: `source`

Stage 2: `where`

Stage 3: `extend`