Shadow Credentials Added to Account (Alternative)

Author: FalconForce
Source: github.com/FalconForceTeam/FalconFriday

This query searches for modifications to the 'msDS-KeyCredentialLink' property in Active Directory. There are two different events which contain information to detect such changes: 5136 and 4662. This detection uses the 4662, which is an alternative if 5136 is not available.

MITRE ATT&CK coverage

Tactic	Techniques
Persistence	`T1098` Account Manipulation
Privilege Escalation	`T1098` Account Manipulation, `T1484` Domain or Tenant Policy Modification

References

Event coverage

Provider	Event	Title
Security-Auditing	Event ID 4662	An operation was performed on an object.

Rule body kusto

let timeframe = 2*1h;
let RuleId = "0297";
let DedupFields = dynamic(["TimeGenerated"]);
SecurityEvent
| where ingestion_time() >= ago(timeframe)
| where EventID == 4662
| where Properties has "5b47d60f-6090-40b2-9f37-2a4de88f3063" // msDS-KeyCredentialLink.
| where Properties has "%%7685" or (binary_and(toint(AccessMask), 0x10) == 0x10) // "Write Property" or "Write Extended Attributes": https://gist.github.com/brianreitz/d5b9397a2e8b3d52ceb9359897e07c3f
| extend HostName=tostring(split(Computer,".")[0]),DnsDomain=iif(Computer contains ".", substring(Computer, indexof(Computer, ".") + 1, strlen(Computer)),"")
| extend AccountName=iif(Account contains @"\",tostring(split(Account,@"\")[1]),Account),AccountDomain=iif(Account contains @"\",tostring(split(Account,@"\")[0]),"")    
// Begin environment-specific filter.
// End environment-specific filter.
// Begin de-duplication logic.
| extend DedupFieldValues=pack_all()
| mv-apply e=DedupFields to typeof(string) on (
    extend DedupValue=DedupFieldValues[tostring(e)]
    | order by e // Sorting is required to ensure make_list is deterministic.
    | summarize DedupValues=make_list(DedupValue)
)
| extend DedupEntity=strcat_array(DedupValues, "|")
| project-away DedupFieldValues, DedupValues
| join kind=leftanti (
    SecurityAlert
    | where AlertName has RuleId and ProviderName has "ASI"
    | where TimeGenerated >= ago(timeframe)
    | extend DedupEntity = tostring(parse_json(tostring(parse_json(ExtendedProperties)["Custom Details"])).DedupEntity[0])
    | project DedupEntity
) on DedupEntity
// End de-duplication logic.

Stages and Predicates

Parameters

let timeframe = 2*1h;
let RuleId = "0297";
let DedupFields = dynamic(["TimeGenerated"]);

Stage 1: `source`

SecurityEvent

Stage 2: `where`

| where ingestion_time() >= ago(timeframe)

Stage 3: `where`

| where EventID == 4662

Stage 4: `where`

| where Properties has "5b47d60f-6090-40b2-9f37-2a4de88f3063"

Stage 5: `where`

| where Properties has "%%7685" or (binary_and(toint(AccessMask), 0x10) == 0x10)

Stage 6: `extend` (3 consecutive steps)

| extend HostName=tostring(split(Computer,".")[0]),DnsDomain=iif(Computer contains ".", substring(Computer, indexof(Computer, ".") + 1, strlen(Computer)),"")
| extend AccountName=iif(Account contains @"\",tostring(split(Account,@"\")[1]),Account),AccountDomain=iif(Account contains @"\",tostring(split(Account,@"\")[0]),"")
| extend DedupFieldValues=pack_all()

Stage 7: `kusto:mv-apply`

| mv-apply e=DedupFields to typeof(string) on (
    extend DedupValue=DedupFieldValues[tostring(e)]
    | order by e
    | summarize DedupValues=make_list(DedupValue)
)

Stage 8: `extend`

| extend DedupEntity=strcat_array(DedupValues, "|")

Stage 9: `project-away`

| project-away DedupFieldValues, DedupValues

Stage 10: `join` (negated)

| join kind=leftanti (
    SecurityAlert
    | where AlertName has RuleId and ProviderName has "ASI"
    | where TimeGenerated >= ago(timeframe)
    | extend DedupEntity = tostring(parse_json(tostring(parse_json(ExtendedProperties)["Custom Details"])).DedupEntity[0])
    | project DedupEntity
) on DedupEntity

Stage 11: `summarize`

summarize

Exclusions

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

Field	Kind	Excluded values
`AlertName`	match	`0297`
`ProviderName`	match	`ASI`

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
`AccessMask`	eq	`16` transforms: `binary_and`
`EventID`	eq	`4662` transforms: `cased` corpus 13 (splunk 7, kusto 4, elastic 1, chronicle 1)
`Properties`	match	`%%7685` transforms: `term` `5b47d60f-6090-40b2-9f37-2a4de88f3063` transforms: `term`

`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)

Shadow Credentials Added to Account (Alternative)

MITRE ATT&CK coverage

References

Event coverage

Rule body kusto

Stages and Predicates

Parameters

Stage 1: `source`

Stage 2: `where`

Stage 3: `where`

Stage 4: `where`

Stage 5: `where`

Stage 6: `extend` (3 consecutive steps)

Stage 7: `kusto:mv-apply`

Stage 8: `extend`

Stage 9: `project-away`

Stage 10: `join` (negated)

Stage 11: `summarize`

Exclusions

Indicators

Keyboard shortcuts

Search operators

Shadow Credentials Added to Account (Alternative)

MITRE ATT&CK coverage

References

Event coverage

Rule body kusto

Stages and Predicates

Parameters

Stage 1: source

Stage 2: where

Stage 3: where

Stage 4: where

Stage 5: where

Stage 6: extend (3 consecutive steps)

Stage 7: kusto:mv-apply

Stage 8: extend

Stage 9: project-away

Stage 10: join (negated)

Stage 11: summarize

Exclusions

Indicators

Stage 1: `source`

Stage 2: `where`

Stage 3: `where`

Stage 4: `where`

Stage 5: `where`

Stage 6: `extend` (3 consecutive steps)

Stage 7: `kusto:mv-apply`

Stage 8: `extend`

Stage 9: `project-away`

Stage 10: `join` (negated)

Stage 11: `summarize`