Failed host logons but success logon to AzureAD

Severity: medium
Time window: 1d
Group by: IpAddress
Author: Microsoft Security Research
Source: github.com/Azure/Azure-Sentinel

Identifies a list of IP addresses with a minimum number(default of 5) of failed logon attempts to remote hosts. Uses that list to identify any successful logons to Microsoft Entra ID from these IPs within the same timeframe.

MITRE ATT&CK coverage

Tactic	Techniques
Initial Access	`T1078` Valid Accounts
Credential Access	`T1110` Brute Force

Event coverage

Provider	Event	Title
Security-Auditing	Event ID 4625	An account failed to log on.

Rule body kusto

id:  1ce5e766-26ab-4616-b7c8-3b33ae321e80
name: Failed host logons but success logon to AzureAD
description: |
  'Identifies a list of IP addresses with a minimum number(default of 5) of failed logon attempts to remote hosts.
  Uses that list to identify any successful logons to Microsoft Entra ID from these IPs within the same timeframe.'
severity: Medium
requiredDataConnectors:
  - connectorId: AzureActiveDirectory
    dataTypes:
     - SigninLogs
  - connectorId: AzureActiveDirectory
    dataTypes:
      - AADNonInteractiveUserSignInLogs
  - connectorId: SecurityEvents
    dataTypes:
      - SecurityEvent
  - connectorId: Syslog
    dataTypes:
      - Syslog 
  - connectorId: WindowsSecurityEvents
    dataTypes: 
      - SecurityEvents 
  - connectorId: WindowsForwardedEvents
    dataTypes: 
      - WindowsEvent 
queryFrequency: 1d
queryPeriod: 1d
triggerOperator: gt
triggerThreshold: 0
tactics:
  - InitialAccess
  - CredentialAccess
relevantTechniques:
  - T1078
  - T1110
  
query: |
  //Adjust this threshold to fit environment
  let signin_threshold = 5; 
  //Make a list of IPs with failed Windows host logins above threshold
  let win_fails = 
  SecurityEvent
  | where EventID == 4625
  | where LogonType in (10, 7, 3)
  | where IpAddress != "-"
  | summarize count() by IpAddress
  | where count_ > signin_threshold
  | summarize make_list(IpAddress);
  let wef_fails =
  WindowsEvent
  | where EventID == 4625
  | extend LogonType = tostring(EventData.LogonType)
  | where LogonType in (10, 7, 3)
  | extend IpAddress = tostring(EventData.IpAddress)
  | where IpAddress != "-"
  | summarize count() by IpAddress
  | where count_ > signin_threshold
  | summarize make_list(IpAddress);
  //Make a list of IPs with failed *nix host logins above threshold
  let nix_fails = 
  Syslog
  | where Facility contains 'auth' and ProcessName != 'sudo' and SyslogMessage has 'from' and not(SyslogMessage has_any ('Disconnecting', 'Disconnected', 'Accepted', 'disconnect', @'[preauth]'))
  | extend SourceIP = extract("(([0-9]{1,3})\\.([0-9]{1,3})\\.([0-9]{1,3})\\.(([0-9]{1,3})))",1,SyslogMessage)
  | where SourceIP != "" and SourceIP != "127.0.0.1"
  | summarize count() by SourceIP
  | where count_ > signin_threshold
  | summarize make_list(SourceIP);
  //See if any of the IPs with failed host logins hve had a sucessful Azure AD login
  let aadFunc = (tableName:string){
  table(tableName)
  | where ResultType in ("0", "50125", "50140")
  | where IPAddress in (win_fails) or IPAddress in (nix_fails) or IPAddress in (wef_fails)
  | extend Reason=  "Multiple failed host logins from IP address with successful Azure AD login"
  | extend timestamp = TimeGenerated, Type = Type
  | extend AccountName = tostring(split(UserPrincipalName, "@")[0]), AccountUPNSuffix = tostring(split(UserPrincipalName, "@")[1])
  };
  let aadSignin = aadFunc("SigninLogs");
  let aadNonInt = aadFunc("AADNonInteractiveUserSignInLogs");
  union isfuzzy=true aadSignin, aadNonInt
entityMappings:
  - entityType: Account
    fieldMappings:
      - identifier: FullName
        columnName: UserPrincipalName
      - identifier: Name
        columnName: AccountName
      - identifier: UPNSuffix
        columnName: AccountUPNSuffix
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: IPAddress
version: 1.1.5
kind: Scheduled
metadata:
    source:
        kind: Community
    author:
        name: Microsoft Security Research
    support:
        tier: Community
    categories:
        domains: [ "Security - Others", "Identity" ]

Stages and Predicates

Parameters

let signin_threshold = 5;
let aadSignin = aadFunc("SigninLogs");
let aadNonInt = aadFunc("AADNonInteractiveUserSignInLogs");

Let binding: `win_fails`

let win_fails = SecurityEvent
| where EventID == 4625
| where LogonType in (10, 7, 3)
| where IpAddress != "-"
| summarize count() by IpAddress
| where count_ > signin_threshold
| summarize make_list(IpAddress);

Derived from signin_threshold.

Let binding: `wef_fails`

let wef_fails = WindowsEvent
| where EventID == 4625
| extend LogonType = tostring(EventData.LogonType)
| where LogonType in (10, 7, 3)
| extend IpAddress = tostring(EventData.IpAddress)
| where IpAddress != "-"
| summarize count() by IpAddress
| where count_ > signin_threshold
| summarize make_list(IpAddress);

Derived from signin_threshold.

Let binding: `nix_fails`

let nix_fails = Syslog
| where Facility contains 'auth' and ProcessName != 'sudo' and SyslogMessage has 'from' and not(SyslogMessage has_any ('Disconnecting', 'Disconnected', 'Accepted', 'disconnect', @'[preauth]'))
| extend SourceIP = extract("(([0-9]{1,3})\\.([0-9]{1,3})\\.([0-9]{1,3})\\.(([0-9]{1,3})))",1,SyslogMessage)
| where SourceIP != "" and SourceIP != "127.0.0.1"
| summarize count() by SourceIP
| where count_ > signin_threshold
| summarize make_list(SourceIP);

Derived from signin_threshold.

Let binding: `aadFunc`

let aadFunc = (tableName:string){
table(tableName)
| where ResultType in ("0", "50125", "50140")
| where IPAddress in (win_fails) or IPAddress in (nix_fails) or IPAddress in (wef_fails)
| extend Reason=  "Multiple failed host logins from IP address with successful Azure AD login"
| extend timestamp = TimeGenerated, Type = Type
| extend AccountName = tostring(split(UserPrincipalName, "@")[0]), AccountUPNSuffix = tostring(split(UserPrincipalName, "@")[1])
};

Derived from win_fails, wef_fails, nix_fails.

union `isfuzzy=true` (2 sources)

Each leg below queries one source; the rule matches if any leg does. Sources: aadSignin, aadNonInt

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`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)

Failed host logons but success logon to AzureAD

MITRE ATT&CK coverage

Event coverage

Rule body kusto

Stages and Predicates

Parameters

Let binding: `win_fails`

Let binding: `wef_fails`

Let binding: `nix_fails`

Let binding: `aadFunc`

union `isfuzzy=true` (2 sources)

Leg 1: `aadSignin`

Leg 2: `aadNonInt`

Keyboard shortcuts

Search operators

Failed host logons but success logon to AzureAD

MITRE ATT&CK coverage

Event coverage

Rule body kusto

Stages and Predicates

Parameters

Let binding: win_fails

Let binding: wef_fails

Let binding: nix_fails

Let binding: aadFunc

union isfuzzy=true (2 sources)

Leg 1: aadSignin

Leg 2: aadNonInt

Let binding: `win_fails`

Let binding: `wef_fails`

Let binding: `nix_fails`

Let binding: `aadFunc`

union `isfuzzy=true` (2 sources)

Leg 1: `aadSignin`

Leg 2: `aadNonInt`