Potential Credential Dumping Activity Via LSASS

Severity: medium
Type: Detection
Time window: 5m
Match by: hostname
Source: github.com/chronicle/detection-rules

Detects process access requests to the LSASS process with specific call trace calls and access masks. This behaviour is expressed by many credential dumping tools such as Mimikatz, NanoDump, Invoke-Mimikatz, Procdump and even the Taskmgr dumping feature.

MITRE ATT&CK coverage

Tactic	Techniques
Credential Access	`T1003.001` OS Credential Dumping: LSASS Memory

References

https://github.com/SigmaHQ/sigma/blob/master/rules/windows/process_access/proc_access_win_lsass_memdump.yml

Event coverage

Provider	Event	Title
Sysmon	Event ID 10	ProcessAccess

Rule body yaral

/*
 * Copyright 2025 Google LLC
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

rule potential_credential_dumping_activity_via_lsass {

  meta:
    author = "Samir Bousseaden, Michael Haag"
    description = "Detects process access requests to the LSASS process with specific call trace calls and access masks. This behaviour is expressed by many credential dumping tools such as Mimikatz, NanoDump, Invoke-Mimikatz, Procdump and even the Taskmgr dumping feature."
    reference = "https://github.com/SigmaHQ/sigma/blob/master/rules/windows/process_access/proc_access_win_lsass_memdump.yml"
    license = "https://github.com/SigmaHQ/Detection-Rule-License/blob/main/LICENSE.Detection.Rules.md"
    rule_name = "Potential Credential Dumping Activity Via LSASS"
    sigma_uuid = "5ef9853e-4d0e-4a70-846f-a9ca37d876da"
    sigma_status = "experimental"
    rule_id = "mr_33474568-9a0a-4588-ba79-144ab7908f8e"
    tactic = "TA0006"
    technique = "T1003.001"
    type = "Detection"
    data_source = "Sysmon"
    platform = "Windows"
    severity = "Medium"
    priority = "Medium"
    false_positives = "Unknown"

  events:
    $process.metadata.event_type = "PROCESS_OPEN"
    re.regex($process.target.process.file.full_path, `\\lsass\.exe$`) nocase
    (
        strings.contains(strings.to_lower($process.target.resource.name), "0x1038") or
        strings.contains(strings.to_lower($process.target.resource.name), "0x1438") or
        strings.contains(strings.to_lower($process.target.resource.name), "0x143a") or
        strings.contains(strings.to_lower($process.target.resource.name), "0x1fffff") //questionable, this one and others have been filtered out due to FP
    )
    (
        strings.contains(strings.to_lower($process.additional.fields["CallTrace"]), "dbgcore.dll") or
        strings.contains(strings.to_lower($process.additional.fields["CallTrace"]), "dbghelp.dll") or
        strings.contains(strings.to_lower($process.additional.fields["CallTrace"]), "kernel32.dll") or
        strings.contains(strings.to_lower($process.additional.fields["CallTrace"]), "kernelbase.dll") or
        strings.contains(strings.to_lower($process.additional.fields["CallTrace"]), "ntdll.dll")
    )
    NOT (
            strings.contains($process.principal.administrative_domain, "AUTHORI") or
            strings.contains($process.principal.administrative_domain, "AUTORI")
        )
    NOT (
        strings.contains(strings.to_lower($process.additional.fields["CallTrace"]), ":\\windows\\temp\\asgard2-agent\\") and
        strings.contains(strings.to_lower($process.additional.fields["CallTrace"]), "\\thor\\thor64.exe+") and
        strings.contains(strings.to_upper($process.additional.fields["CallTrace"]), "|UNKNOWN(") and
        $process.target.resource.name = "0x103800" nocase
        )
    NOT re.regex($process.principal.process.file.full_path, `:\\Windows\\Sysmon64\.exe$`) nocase
    $process.principal.hostname = $hostname

  match:
    $hostname over 5m

  outcome:
    //example usage of specifying test hostname to adjust risk score
    $risk_score = max(if($process.principal.hostname = "hostname", 0, 15))
    $principal_process_pid = array_distinct($process.principal.process.pid)
    $principal_process_command_line = array_distinct($process.principal.process.command_line)
    $principal_process_file_sha256 = array_distinct($process.principal.process.file.sha256)
    $principal_process_file_full_path = array_distinct($process.principal.process.file.full_path)
    $principal_process_product_specfic_process_id = array_distinct($process.principal.process.product_specific_process_id)
    $principal_process_parent_process_product_specfic_process_id = array_distinct($process.principal.process.parent_process.product_specific_process_id)
    $target_process_pid = array_distinct($process.target.process.pid)
    $target_process_command_line = array_distinct($process.target.process.command_line)
    $target_process_file_sha256 = array_distinct($process.target.process.file.sha256)
    $target_process_file_full_path = array_distinct($process.target.process.file.full_path)
    $target_process_product_specfic_process_id = array_distinct($process.target.process.product_specific_process_id)
    $log_type = array_distinct(strings.concat($process.metadata.log_type,"/",$process.metadata.product_event_type))

  condition:
    $process
}

Stages and Predicates

Stage 0: `match + condition`

match:
    $hostname over 5m
condition:
    $process

Fires when at least one $process event in the 5m window.

Stage 1: `events: $process · PROCESS_OPEN`

$process.metadata.event_type = "PROCESS_OPEN"
re.regex($process.target.process.file.full_path, `\\lsass\.exe$`) nocase
(
    strings.contains(strings.to_lower($process.target.resource.name), "0x1038") or
    strings.contains(strings.to_lower($process.target.resource.name), "0x1438") or
    strings.contains(strings.to_lower($process.target.resource.name), "0x143a") or
    strings.contains(strings.to_lower($process.target.resource.name), "0x1fffff") //questionable, this one and others have been filtered out due to FP
)
(
    strings.contains(strings.to_lower($process.additional.fields["CallTrace"]), "dbgcore.dll") or
    strings.contains(strings.to_lower($process.additional.fields["CallTrace"]), "dbghelp.dll") or
    strings.contains(strings.to_lower($process.additional.fields["CallTrace"]), "kernel32.dll") or
    strings.contains(strings.to_lower($process.additional.fields["CallTrace"]), "kernelbase.dll") or
    strings.contains(strings.to_lower($process.additional.fields["CallTrace"]), "ntdll.dll")
)
NOT (
        strings.contains($process.principal.administrative_domain, "AUTHORI") or
        strings.contains($process.principal.administrative_domain, "AUTORI")
    )
NOT (
    strings.contains(strings.to_lower($process.additional.fields["CallTrace"]), ":\\windows\\temp\\asgard2-agent\\") and
    strings.contains(strings.to_lower($process.additional.fields["CallTrace"]), "\\thor\\thor64.exe+") and
    strings.contains(strings.to_upper($process.additional.fields["CallTrace"]), "|UNKNOWN(") and
    $process.target.resource.name = "0x103800" nocase
    )
NOT re.regex($process.principal.process.file.full_path, `:\\Windows\\Sysmon64\.exe$`) nocase
$process.principal.hostname = $hostname

Exclusions

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

Stage	Field	Kind	Excluded values
1	`additional.fields["CallTrace"]`	contains	`:\\windows\\temp\\asgard2-agent\\`
1	`additional.fields["CallTrace"]`	contains	`\\thor\\thor64.exe+`
1	`additional.fields["CallTrace"]`	contains	`\|UNKNOWN(`
1	`target.resource.name`	eq	`0x103800`
1	`principal.administrative_domain`	contains	`AUTHORI`
1	`principal.administrative_domain`	contains	`AUTORI`
1	`principal.process.file.full_path`	regex_match	`:\Windows\Sysmon64.exe$`

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
`additional.fields["CallTrace"]`	contains	`dbgcore.dll` transforms: `tolower` `dbghelp.dll` transforms: `tolower` `kernel32.dll` transforms: `tolower` `kernelbase.dll` transforms: `tolower` `ntdll.dll` transforms: `tolower`
`target.process.file.full_path`	regex_match	`\lsass.exe$` transforms: `nocase` corpus 3 (chronicle 3)
`target.resource.name`	contains	`0x1038` transforms: `tolower` `0x1438` transforms: `tolower` `0x143a` transforms: `tolower` `0x1fffff` transforms: `tolower`

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
`risk_score`	`max(if($process.principal.hostname = "hostname", 0, 15))`
`principal_process_pid`	`array_distinct($process.principal.process.pid)`
`principal_process_command_line`	`array_distinct($process.principal.process.command_line)`
`principal_process_file_sha256`	`array_distinct($process.principal.process.file.sha256)`
`principal_process_file_full_path`	`array_distinct($process.principal.process.file.full_path)`
`principal_process_product_specfic_process_id`	`array_distinct($process.principal.process.product_specific_process_id)`
`principal_process_parent_process_product_specfic_process_id`	`array_distinct($process.principal.process.parent_process.product_specific_process_id)`
`target_process_pid`	`array_distinct($process.target.process.pid)`
`target_process_command_line`	`array_distinct($process.target.process.command_line)`
`target_process_file_sha256`	`array_distinct($process.target.process.file.sha256)`
`target_process_file_full_path`	`array_distinct($process.target.process.file.full_path)`
`target_process_product_specfic_process_id`	`array_distinct($process.target.process.product_specific_process_id)`
`log_type`	`array_distinct(strings.concat($process.metadata.log_type,"/",$process.metadata.product_event_type))`

`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:`)
`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)

Potential Credential Dumping Activity Via LSASS

MITRE ATT&CK coverage

References

Event coverage

Rule body yaral

Stages and Predicates

Stage 0: `match + condition`

Stage 1: `events: $process · PROCESS_OPEN`

Exclusions

Indicators

Output fields

Keyboard shortcuts

Search operators

Potential Credential Dumping Activity Via LSASS

MITRE ATT&CK coverage

References

Event coverage

Rule body yaral

Stages and Predicates

Stage 0: match + condition

Stage 1: events: $process · PROCESS_OPEN

Exclusions

Indicators

Output fields

Stage 0: `match + condition`

Stage 1: `events: $process · PROCESS_OPEN`