NTLM Relay Attack

Group by: RemoteDeviceName, RemoteIP, ShortDeviceName
Author: FalconForce
Source: github.com/FalconForceTeam/FalconFriday

This query searches for successful NTLM network logins where the device name contained in the NTLM authentication message contains a device that is known to MDE, but the source IP address is different from the known source IP address for that specific device. This could indicate an attacker is relaying the NTLM authentication information. To remove false positives, this query also searches for an outgoing network connection from the initiator to the attacker.

MITRE ATT&CK coverage

Tactic	Techniques
Credential Access	`T1187` Forced Authentication, `T1557.001` Adversary-in-the-Middle: Name Resolution Poisoning and SMB Relay

References

https://github.com/Cyb3r-Monk/Threat-Hunting-and-Detection/blob/main/Credential%20Access/Potentially%20Relayed%20NTLM%20Authentication%20-%20MDE.md

Event coverage

Provider	Event/ActionType	Title
Sysmon	Event ID 3	Network connection
Security-Auditing	Event ID 4624	An account was successfully logged on.
Security-Auditing	Event ID 5156	The Windows Filtering Platform has permitted a connection.
Defender-DeviceLogonEvents	LogonSuccess	Logon succeeded
Defender-DeviceNetworkEvents	ConnectionSuccess	Connection succeeded
Defender-DeviceNetworkEvents	ConnectionAttempt	Connection attempt

Rule body kusto

let timeframe = 2*1d;
// Extract a list of known local IPs per device. Note that the DeviceNetworkEvents table is used for this, since this is faster than the
// DeviceNetworkInfo table where IP addresses are stored inside a JSON structure that requires additional parsing.
let DeviceIPs=(
    DeviceNetworkEvents
    | where ingestion_time() >= ago(timeframe)
    | where ActionType == "ConnectionAttempt" or ActionType == "ConnectionSuccess"
    | distinct DeviceName, LocalIP
    | extend DeviceName=tolower(split(DeviceName,".")[0])
);
// Find potential NTLM relay attack by looking for NTLM logins from devices that are known in MDE, but are from a source IP that does not match any known IP addresses for the device.
let PotentialNTLMRelayLogins=materialize (
    DeviceLogonEvents
    | where ingestion_time() >= ago(timeframe)
    | where ActionType == "LogonSuccess"
    | where LogonType == "Network"
    | where Protocol=="NTLM"
    | where isnotempty(RemoteDeviceName) and isnotempty(RemoteIP)
    | where RemoteIPType <> "Loopback"
    | extend RemoteDeviceName=tolower(RemoteDeviceName)
    | where RemoteDeviceName in ((DeviceIPs | project DeviceName)) // The remote device is known in MDE.
    | join kind=leftanti DeviceIPs on $left.RemoteIP == $right.LocalIP, $left.RemoteDeviceName == $right.DeviceName // The Remote IP does not match any known IP for the device.
    | project-reorder Timestamp, RemoteIP, RemoteDeviceName, AccountDomain, AccountName
);
// Filter the potential NTLM relay events by checking there was an outgoing SMB connection from the source device to the relay IP address.
DeviceNetworkEvents
| where ingestion_time() >= ago(timeframe)
| where RemotePort in (445, 80, 9389)
| where RemoteIP in ((PotentialNTLMRelayLogins | project RemoteIP))
| extend ShortDeviceName=tolower(split(DeviceName,".")[0])
| where ShortDeviceName in ((PotentialNTLMRelayLogins | project RemoteDeviceName))
| lookup kind=inner PotentialNTLMRelayLogins on $left.ShortDeviceName == $right.RemoteDeviceName, $left.RemoteIP == $right.RemoteIP
| extend HostName=tostring(split(DeviceName,".")[0]),DnsDomain=iif(DeviceName contains ".", substring(DeviceName, indexof(DeviceName, ".") + 1, strlen(DeviceName)),"")
// Begin environment-specific filter.
// End environment-specific filter.

Stages and Predicates

Parameters

let timeframe = 2*1d;

Let binding: `DeviceIPs`

let DeviceIPs = (
    DeviceNetworkEvents
    | where ingestion_time() >= ago(timeframe)
    | where ActionType == "ConnectionAttempt" or ActionType == "ConnectionSuccess"
    | distinct DeviceName, LocalIP
    | extend DeviceName=tolower(split(DeviceName,".")[0])
);

Derived from timeframe.

Let binding: `PotentialNTLMRelayLogins`

let PotentialNTLMRelayLogins = materialize (
    DeviceLogonEvents
    | where ingestion_time() >= ago(timeframe)
    | where ActionType == "LogonSuccess"
    | where LogonType == "Network"
    | where Protocol=="NTLM"
    | where isnotempty(RemoteDeviceName) and isnotempty(RemoteIP)
    | where RemoteIPType <> "Loopback"
    | extend RemoteDeviceName=tolower(RemoteDeviceName)
    | where RemoteDeviceName in ((DeviceIPs | project DeviceName))
    | join kind=leftanti DeviceIPs on $left.RemoteIP == $right.LocalIP, $left.RemoteDeviceName == $right.DeviceName
    | project-reorder Timestamp, RemoteIP, RemoteDeviceName, AccountDomain, AccountName
);

Derived from timeframe, DeviceIPs.

Stage 1: `source`

DeviceNetworkEvents

Stage 2: `where`

| where ingestion_time() >= ago(timeframe)

Stage 3: `where`

| where RemotePort in (445, 80, 9389)

Stage 4: `where`

| where RemoteIP in ((PotentialNTLMRelayLogins | project RemoteIP))

Stage 5: `extend`

| extend ShortDeviceName=tolower(split(DeviceName,".")[0])

Stage 6: `where`

| where ShortDeviceName in ((PotentialNTLMRelayLogins | project RemoteDeviceName))

Stage 7: `kusto:lookup`

| lookup kind=inner PotentialNTLMRelayLogins on $left.ShortDeviceName == $right.RemoteDeviceName, $left.RemoteIP == $right.RemoteIP

Stage 8: `extend`

| extend HostName=tostring(split(DeviceName,".")[0]),DnsDomain=iif(DeviceName contains ".", substring(DeviceName, indexof(DeviceName, ".") + 1, strlen(DeviceName)),"")

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
`RemotePort`	in	`445` transforms: `cased` corpus 8 (elastic 5, splunk 2, sigma 1) `80` transforms: `cased` corpus 10 (sigma 6, elastic 2, kusto 2) `9389` transforms: `cased` corpus 5 (kusto 2, sigma 1, elastic 1, splunk 1)

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
`ShortDeviceName`	`extend`
`DnsDomain`	`extend`
`HostName`	`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)

NTLM Relay Attack

MITRE ATT&CK coverage

References

Event coverage

Rule body kusto

Stages and Predicates

Parameters

Let binding: `DeviceIPs`

Let binding: `PotentialNTLMRelayLogins`

Stage 1: `source`

Stage 2: `where`

Stage 3: `where`

Stage 4: `where`

Stage 5: `extend`

Stage 6: `where`

Stage 7: `kusto:lookup`

Stage 8: `extend`

Indicators

Output fields

Keyboard shortcuts

Search operators

NTLM Relay Attack

MITRE ATT&CK coverage

References

Event coverage

Rule body kusto

Stages and Predicates

Parameters

Let binding: DeviceIPs

Let binding: PotentialNTLMRelayLogins

Stage 1: source

Stage 2: where

Stage 3: where

Stage 4: where

Stage 5: extend

Stage 6: where

Stage 7: kusto:lookup

Stage 8: extend

Indicators

Output fields

Let binding: `DeviceIPs`

Let binding: `PotentialNTLMRelayLogins`

Stage 1: `source`

Stage 2: `where`

Stage 3: `where`

Stage 4: `where`

Stage 5: `extend`

Stage 6: `where`

Stage 7: `kusto:lookup`

Stage 8: `extend`