Request for single resource on domain

Status: available
Severity: low
Time window: 1d
Group by: Domain
Source: github.com/Azure/Azure-Sentinel

'This will look for connections to a domain where only a single file is requested, this is unusual as most modern web applications require additional recources. This type of activity is often assocaited with malware beaconing or tracking URL's delivered in emails. Developed for Zscaler but applicable to any outbound web logging.'

MITRE ATT&CK coverage

Tactic	Techniques
Command & Control	`T1071` Application Layer Protocol, `T1102` Web Service

Rule body kusto

id: 4d500e6d-c984-43a3-9f39-7edec8dcc04d
name: Request for single resource on domain
description: |
  'This will look for connections to a domain where only a single file is requested, this is unusual as most modern web applications require additional recources. This type of activity is often assocaited with malware beaconing or tracking URL's delivered in emails. Developed for Zscaler but applicable to any outbound web logging.'
severity: Low
status: Available
requiredDataConnectors:
  - connectorId: CefAma
    dataTypes:
      - CommonSecurityLog
queryFrequency: 1d
queryPeriod: 1d
triggerOperator: gt
triggerThreshold: 0
tactics:
  - CommandAndControl
relevantTechniques:
  - T1102
  - T1071
query: |
  let scriptExtensions = dynamic([".php", ".aspx", ".asp", ".cfml"]);
  //The number of URI's seen to be suspicious, higher = less likely to be suspicious
  let uriThreshold = 1;
  CommonSecurityLog
  // Only look at connections that were allowed through the web proxy
  | where DeviceVendor =~ "Zscaler" and DeviceAction =~ "Allowed"
  // Only look where some data was exchanged.
  | where SentBytes > 0 and ReceivedBytes > 0
  // Extract the Domain
  | extend Domain = iff(countof(DestinationHostName,'.') >= 2, strcat(split(DestinationHostName,'.')[-2], '.',split(DestinationHostName,'.')[-1]), DestinationHostName)
  | extend GetData=iff(RequestURL == "?", 1, 0)
  | summarize StartTimeUtc = min(TimeGenerated), EndTimeUtc = max(TimeGenerated), makelist(RequestURL), makelist(DestinationIP), makelist(SourceIP), numOfConnections = count(), make_set(RequestMethod), max(GetData), max(RequestContext) by Domain
  // Determine the number of URIs that have been visited for the domain
  | extend destinationURI = arraylength(list_RequestURL)
  | where destinationURI <= uriThreshold
  | where tostring(list_RequestURL) has_any(scriptExtensions)
  //Remove matches with referer
  | where max_RequestContext == ""
  //Keep requests where data was trasferred either in a GET with parameters or a POST
  | where set_RequestMethod in~ ("POST") or max_GetData == 1
  //Defeat email click tracking, may increase FN's while decreasing FP's
  | where list_RequestURL !has "click" and set_RequestMethod !has "GET"
  | mvexpand list_RequestURL, list_DestinationIP
  | extend RequestURL = tostring(list_RequestURL), DestinationIP = tostring(list_DestinationIP), ClientIP = tostring(list_SourceIP)
  //Extend custom entitites for incidents
  | project-away list_RequestURL, list_DestinationIP, list_SourceIP, destinationURI, Domain, StartTimeUtc, EndTimeUtc, max_GetData, max_RequestContext
entityMappings:
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: DestinationIP
version: 1.0.5
kind: Scheduled

Stages and Predicates

Parameters

let scriptExtensions = dynamic([".php", ".aspx", ".asp", ".cfml"]);
let uriThreshold = 1;

Stage 1: `source`

CommonSecurityLog

Stage 2: `where`

| where DeviceVendor =~ "Zscaler" and DeviceAction =~ "Allowed"

Stage 3: `where`

| where SentBytes > 0 and ReceivedBytes > 0

Stage 4: `extend`

| extend Domain = iff(countof(DestinationHostName,'.') >= 2, strcat(split(DestinationHostName,'.')[-2], '.',split(DestinationHostName,'.')[-1]), DestinationHostName)

Domain =

if/* macro: (countof(DestinationHostName, '.') >= 2) */strcat(split(DestinationHostName, '.')[(- 2)], '.', split(DestinationHostName, '.')[(- 1)])

elseDestinationHostName

Stage 5: `extend`

| extend GetData=iff(RequestURL == "?", 1, 0)

GetData =

ifRequestURL matches regex "."1

else0

Stage 6: `summarize`

| summarize StartTimeUtc = min(TimeGenerated), EndTimeUtc = max(TimeGenerated), makelist(RequestURL), makelist(DestinationIP), makelist(SourceIP), numOfConnections = count(), make_set(RequestMethod), max(GetData), max(RequestContext) by Domain

Stage 7: `extend`

| extend destinationURI = arraylength(list_RequestURL)

Stage 8: `where`

| where destinationURI <= uriThreshold

Stage 9: `where`

| where tostring(list_RequestURL) has_any(scriptExtensions)

Stage 10: `where`

| where max_RequestContext == ""

Stage 11: `where`

| where set_RequestMethod in~ ("POST") or max_GetData == 1

Stage 12: `where`

| where list_RequestURL !has "click" and set_RequestMethod !has "GET"

Stage 13: `mv-expand`

| mvexpand list_RequestURL, list_DestinationIP

Stage 14: `extend`

| extend RequestURL = tostring(list_RequestURL), DestinationIP = tostring(list_DestinationIP), ClientIP = tostring(list_SourceIP)

Stage 15: `project-away`

| project-away list_RequestURL, list_DestinationIP, list_SourceIP, destinationURI, Domain, StartTimeUtc, EndTimeUtc, max_GetData, max_RequestContext

Exclusions

Top-level NOT(...) conjuncts: predicates this rule actively suppresses.

Field	Kind	Excluded values
`list_RequestURL`	match	`click`
`set_RequestMethod`	match	`GET`

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
`DeviceAction`	eq	`Allowed`
`DeviceVendor`	eq	`Zscaler`
`ReceivedBytes`	gt	`0` transforms: `cased`
`SentBytes`	gt	`0` transforms: `cased`
`destinationURI`	le	`1` transforms: `cased`
`list_RequestURL`	match	`.asp` transforms: `tostring` `.aspx` transforms: `tostring` `.cfml` transforms: `tostring` `.php` transforms: `tostring`
`max_GetData`	eq	`1` transforms: `cased`
`set_RequestMethod`	in	`POST`

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
`numOfConnections`	`summarize`
`ClientIP`	`extend`
`DestinationIP`	`extend`
`RequestURL`	`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)

Request for single resource on domain

MITRE ATT&CK coverage

Rule body kusto

Stages and Predicates

Parameters

Stage 1: `source`

Stage 2: `where`

Stage 3: `where`

Stage 4: `extend`

Stage 5: `extend`

Stage 6: `summarize`

Stage 7: `extend`

Stage 8: `where`

Stage 9: `where`

Stage 10: `where`

Stage 11: `where`

Stage 12: `where`

Stage 13: `mv-expand`

Stage 14: `extend`

Stage 15: `project-away`

Exclusions

Indicators

Output fields

Keyboard shortcuts

Search operators

Request for single resource on domain

MITRE ATT&CK coverage

Rule body kusto

Stages and Predicates

Parameters

Stage 1: source

Stage 2: where

Stage 3: where

Stage 4: extend

Stage 5: extend

Stage 6: summarize

Stage 7: extend

Stage 8: where

Stage 9: where

Stage 10: where

Stage 11: where

Stage 12: where

Stage 13: mv-expand

Stage 14: extend

Stage 15: project-away

Exclusions

Indicators

Output fields

Stage 1: `source`

Stage 2: `where`

Stage 3: `where`

Stage 4: `extend`

Stage 5: `extend`

Stage 6: `summarize`

Stage 7: `extend`

Stage 8: `where`

Stage 9: `where`

Stage 10: `where`

Stage 11: `where`

Stage 12: `where`

Stage 13: `mv-expand`

Stage 14: `extend`

Stage 15: `project-away`