Detection rules › YARA-L

LSASS Dump Keyword In CommandLine

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

Detects the presence of the keywords lsass and .dmp in the commandline, which could indicate a potential attempt to dump or create a dump of the lsass process

MITRE ATT&CK coverage

TacticTechniques
Credential AccessT1003.001 OS Credential Dumping: LSASS Memory

References

Event coverage

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 lsass_dump_keyword_command_line {

  meta:
    author = "E.M. Anhaus, Tony Lambert, oscd.community, Nasreddine Bencherchali (Nextron Systems)"
    description = "Detects the presence of the keywords lsass and .dmp in the commandline, which could indicate a potential attempt to dump or create a dump of the lsass process"
    reference = "https://github.com/SigmaHQ/sigma/blob/master/rules/windows/process_creation/proc_creation_win_susp_lsass_dmp_cli_keywords.yml"
    license = "https://github.com/SigmaHQ/Detection-Rule-License/blob/main/LICENSE.Detection.Rules.md"
    rule_name = "LSASS Dump Keyword In CommandLine"
    sigma_uuid = "ffa6861c-4461-4f59-8a41-578c39f3f23e"
    sigma_status = "test"
    rule_id = "mr_b7e51852-e836-4020-9ea4-7d9f9ace350f"
    tactic = "TA0006"
    technique = "T1003.001"
    type = "Detection"
    data_source = "Windows Event, Sysmon"
    platform = "Windows"
    severity = "High"
    priority = "High"
    false_positives = "Unlikely"

  events:
    $process.metadata.event_type = "PROCESS_LAUNCH"
    (
        (
            strings.contains(strings.to_lower($process.target.process.command_line), "lsass.dmp") or
            strings.contains(strings.to_lower($process.target.process.command_line), "lsass.zip") or
            strings.contains(strings.to_lower($process.target.process.command_line), "lsass.rar") or
            strings.contains(strings.to_lower($process.target.process.command_line), "andrew.dmp") or
            strings.contains(strings.to_lower($process.target.process.command_line), "coredump.dmp") or
            strings.contains(strings.to_lower($process.target.process.command_line), "notlsass.zip") or
            strings.contains(strings.to_lower($process.target.process.command_line), "lsass_2") or
            strings.contains(strings.to_lower($process.target.process.command_line), "lsassdump") or
            strings.contains(strings.to_lower($process.target.process.command_line), "lsassdmp")
        )
        or
        (
            strings.contains(strings.to_lower($process.target.process.command_line), "lsass") and
            strings.contains(strings.to_lower($process.target.process.command_line), ".dmp")
        )
        or
        (
            strings.contains(strings.to_lower($process.target.process.command_line), "sqldmpr") and
            strings.contains(strings.to_lower($process.target.process.command_line), ".mdmp")
        )
        or
        (
            strings.contains(strings.to_lower($process.target.process.command_line), "nanodump") and
            strings.contains(strings.to_lower($process.target.process.command_line), ".dmp")
        )
    )
    $process.principal.hostname = $hostname

  match:
    $hostname over 5m

  outcome:
    //example usage of specifying test user and hostname to adjust risk score
    $risk_score = max(if($process.principal.user.userid = "user" and $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)
    $principal_user_userid = array_distinct($process.principal.user.userid)
    $log_type = array_distinct(strings.concat($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_LAUNCH

$process.metadata.event_type = "PROCESS_LAUNCH"
(
    (
        strings.contains(strings.to_lower($process.target.process.command_line), "lsass.dmp") or
        strings.contains(strings.to_lower($process.target.process.command_line), "lsass.zip") or
        strings.contains(strings.to_lower($process.target.process.command_line), "lsass.rar") or
        strings.contains(strings.to_lower($process.target.process.command_line), "andrew.dmp") or
        strings.contains(strings.to_lower($process.target.process.command_line), "coredump.dmp") or
        strings.contains(strings.to_lower($process.target.process.command_line), "notlsass.zip") or
        strings.contains(strings.to_lower($process.target.process.command_line), "lsass_2") or
        strings.contains(strings.to_lower($process.target.process.command_line), "lsassdump") or
        strings.contains(strings.to_lower($process.target.process.command_line), "lsassdmp")
    )
    or
    (
        strings.contains(strings.to_lower($process.target.process.command_line), "lsass") and
        strings.contains(strings.to_lower($process.target.process.command_line), ".dmp")
    )
    or
    (
        strings.contains(strings.to_lower($process.target.process.command_line), "sqldmpr") and
        strings.contains(strings.to_lower($process.target.process.command_line), ".mdmp")
    )
    or
    (
        strings.contains(strings.to_lower($process.target.process.command_line), "nanodump") and
        strings.contains(strings.to_lower($process.target.process.command_line), ".dmp")
    )
)
$process.principal.hostname = $hostname

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.

FieldKindValues
target.process.command_linecontains
  • .dmp transforms: tolower corpus 10 (sigma 8, chronicle 2)
  • .mdmp transforms: tolower corpus 2 (sigma 1, chronicle 1)
  • andrew.dmp transforms: tolower corpus 2 (sigma 1, chronicle 1)
  • coredump.dmp transforms: tolower corpus 2 (sigma 1, chronicle 1)
  • lsass transforms: tolower corpus 9 (sigma 6, kusto 2, chronicle 1)
  • lsass.dmp transforms: tolower corpus 2 (sigma 1, chronicle 1)
  • lsass.rar transforms: tolower corpus 2 (sigma 1, chronicle 1)
  • lsass.zip transforms: tolower corpus 2 (sigma 1, chronicle 1)
  • lsass_2 transforms: tolower corpus 2 (sigma 1, chronicle 1)
  • lsassdmp transforms: tolower corpus 2 (sigma 1, chronicle 1)
  • lsassdump transforms: tolower corpus 2 (sigma 1, chronicle 1)
  • nanodump transforms: tolower corpus 2 (sigma 1, chronicle 1)
  • notlsass.zip transforms: tolower corpus 2 (sigma 1, chronicle 1)
  • sqldmpr transforms: tolower corpus 2 (sigma 1, chronicle 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.

FieldSource
risk_scoremax(if($process.principal.user.userid = "user" and $process.principal.hostname = "hostname", 0, 15))
principal_process_pidarray_distinct($process.principal.process.pid)
principal_process_command_linearray_distinct($process.principal.process.command_line)
principal_process_file_sha256array_distinct($process.principal.process.file.sha256)
principal_process_file_full_patharray_distinct($process.principal.process.file.full_path)
principal_process_product_specfic_process_idarray_distinct($process.principal.process.product_specific_process_id)
principal_process_parent_process_product_specfic_process_idarray_distinct($process.principal.process.parent_process.product_specific_process_id)
target_process_pidarray_distinct($process.target.process.pid)
target_process_command_linearray_distinct($process.target.process.command_line)
target_process_file_sha256array_distinct($process.target.process.file.sha256)
target_process_file_full_patharray_distinct($process.target.process.file.full_path)
target_process_product_specfic_process_idarray_distinct($process.target.process.product_specific_process_id)
principal_user_useridarray_distinct($process.principal.user.userid)
log_typearray_distinct(strings.concat($process.metadata.log_type,"/",$process.metadata.product_event_type))