Detect changes to Connect Sync Application

Author: Robbe Van den Daele
Source: github.com/HybridBrothers/Hunting-Queries-Detection-Rules

This detection flags any changes happening on the Connect Sync Application in Entra ID. Since this is a very interesting account for attackers to abuse when moving laterally between AD DS and Entra ID, any change to the account should be investigated. We try to exclude legitimate certificate renewal processes, and a new account onboarding in the detection rule.

MITRE ATT&CK coverage

Tactic	Techniques
Initial Access	`T1078.004` Valid Accounts: Cloud Accounts
Persistence	`T1078.004` Valid Accounts: Cloud Accounts, `T1098` Account Manipulation, `T1556.007` Modify Authentication Process: Hybrid Identity
Privilege Escalation	`T1078.004` Valid Accounts: Cloud Accounts, `T1098` Account Manipulation
Stealth	`T1078.004` Valid Accounts: Cloud Accounts
Defense Impairment	`T1556.007` Modify Authentication Process: Hybrid Identity
Credential Access	`T1556.007` Modify Authentication Process: Hybrid Identity

References

https://specterops.io/blog/2025/06/09/update-dumping-entra-connect-sync-credentials/

Event coverage

Provider	Event	Title
Entra-AuditLogs	_catch_all	Entra ID audit event (any operation)

Rule body yaml

// Flag everything except a renewal process and onboarding
let base = materialize (
    AuditLogs
    // Search events happening on the Sync Account
    | extend AppName = tostring(TargetResources[0].displayName)
    | where AppName startswith "ConnectSyncProvisioning_"
    // Only get cretificate or secret changes
    | where OperationName contains "Update application – Certificates and secrets management"
    // Expand the target resources and modified properties, and only use events ralted to KeyDescription
    | mv-expand TargetResources
    | extend ModifiedProperties = TargetResources.modifiedProperties
    | mv-expand ModifiedProperties
    | where ModifiedProperties.displayName == "KeyDescription"
    // Save the old and new values of the secrets on the application
    | extend OldValue = tostring(ModifiedProperties.oldValue), 
        NewValue = tostring(ModifiedProperties.newValue)
    // Save the old and new credential names in an array
    | extend OldCredentialNames = extract_all(@"DisplayName=([^\]]+)", dynamic([1]), OldValue),
        NewCredentialNames = extract_all(@"DisplayName=([^\]]+)", dynamic([1]), NewValue)
);
let newCredsAdd = (
    base
    // Flag when there are more new credentials than old ones
    | where array_length(OldCredentialNames) < array_length(NewCredentialNames)
    | project-rename NewCredAddTimeGenerated = TimeGenerated
);
let credRemove = (
    base
    // Get events where credentials are being removed
    | where array_length(OldCredentialNames) > array_length(NewCredentialNames)
    | project-rename CredRemoveTimeGenerated = TimeGenerated
);
let credRenewal = (
    // Find legitimate credential renewals
    newCredsAdd
    | join kind=leftouter credRemove on AppName
    | where CredRemoveTimeGenerated - NewCredAddTimeGenerated <= 1m
);
AuditLogs
| extend AppName = tostring(TargetResources[0].displayName)
| where AppName startswith "ConnectSyncProvisioning_"
| join kind=leftanti credRenewal on CorrelationId
// Exclude cred removes (duplicate / not interesting)
| join kind=leftanti credRemove on CorrelationId
// Exclude new deployment
| where OperationName !in ("Add service principal", "Add application")

Stages and Predicates

Let binding: `base`

let base = materialize (
    AuditLogs
    | extend AppName = tostring(TargetResources[0].displayName)
    | where AppName startswith "ConnectSyncProvisioning_"
    | where OperationName contains "Update application – Certificates and secrets management"
    | mv-expand TargetResources
    | extend ModifiedProperties = TargetResources.modifiedProperties
    | mv-expand ModifiedProperties
    | where ModifiedProperties.displayName == "KeyDescription"
    | extend OldValue = tostring(ModifiedProperties.oldValue), 
        NewValue = tostring(ModifiedProperties.newValue)
    | extend OldCredentialNames = extract_all(@"DisplayName=([^\]]+)", dynamic([1]), OldValue),
        NewCredentialNames = extract_all(@"DisplayName=([^\]]+)", dynamic([1]), NewValue)
);

Let binding: `newCredsAdd`

let newCredsAdd = (
    base
    | where array_length(OldCredentialNames) < array_length(NewCredentialNames)
    | project-rename NewCredAddTimeGenerated = TimeGenerated
);

Derived from base.

Let binding: `credRemove`

let credRemove = (
    base
    | where array_length(OldCredentialNames) > array_length(NewCredentialNames)
    | project-rename CredRemoveTimeGenerated = TimeGenerated
);

Derived from base.

Let binding: `credRenewal`

let credRenewal = (
    newCredsAdd
    | join kind=leftouter credRemove on AppName
    | where CredRemoveTimeGenerated - NewCredAddTimeGenerated <= 1m
);

Derived from newCredsAdd, credRemove.

Stage 1: `source`

AuditLogs

Stage 2: `extend`

| extend AppName = tostring(TargetResources[0].displayName)

Stage 3: `where`

| where AppName startswith "ConnectSyncProvisioning_"

Stage 4: `join` (negated)

| join kind=leftanti credRenewal on CorrelationId

Stage 5: `join` (negated)

| join kind=leftanti credRemove on CorrelationId

Stage 6: `where`

| where OperationName !in ("Add service principal", "Add application")

Exclusions

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

Field	Kind	Excluded values
`AppName`	starts_with	`ConnectSyncProvisioning_`
`OldCredentialNames`	cross_field_compare	`NewCredentialNames`
`OldCredentialNames`	cross_field_compare	`NewCredentialNames`
`OperationName`	contains	`Update application – Certificates and secrets management`
`displayName`	eq	`KeyDescription`
`AppName`	starts_with	`ConnectSyncProvisioning_`
`OldCredentialNames`	cross_field_compare	`NewCredentialNames`
`OperationName`	contains	`Update application – Certificates and secrets management`
`displayName`	eq	`KeyDescription`
`OperationName`	in	`Add application`, `Add service principal`

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
`AppName`	starts_with	`ConnectSyncProvisioning_`

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
`AppName`	`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)

Detect changes to Connect Sync Application

MITRE ATT&CK coverage

References

Event coverage

Rule body yaml

Stages and Predicates

Let binding: `base`

Let binding: `newCredsAdd`

Let binding: `credRemove`

Let binding: `credRenewal`

Stage 1: `source`

Stage 2: `extend`

Stage 3: `where`

Stage 4: `join` (negated)

Stage 5: `join` (negated)

Stage 6: `where`

Exclusions

Indicators

Output fields

Keyboard shortcuts

Search operators

Detect changes to Connect Sync Application

MITRE ATT&CK coverage

References

Event coverage

Rule body yaml

Stages and Predicates

Let binding: base

Let binding: newCredsAdd

Let binding: credRemove

Let binding: credRenewal

Stage 1: source

Stage 2: extend

Stage 3: where

Stage 4: join (negated)

Stage 5: join (negated)

Stage 6: where

Exclusions

Indicators

Output fields

Let binding: `base`

Let binding: `newCredsAdd`

Let binding: `credRemove`

Let binding: `credRenewal`

Stage 1: `source`

Stage 2: `extend`

Stage 3: `where`

Stage 4: `join` (negated)

Stage 5: `join` (negated)

Stage 6: `where`