Detectionmediumtest

Potentially Suspicious AccessMask Requested From LSASS

Detects process handle on LSASS process with certain access mask

Convert In Phoenix Studio

Open this Sigma rule in the converter with the YAML preloaded and ready for backend selection.

Launch
Roberto Rodriguez (Cyb3rWard0g), Teymur Kheirkhabarov, Dimitrios Slamaris, Mark Russinovich, Aleksey Potapov, oscd.communityCreated Fri Nov 01Updated Tue Dec 194a1b6da0-d94f-4fc3-98fc-2d9cb9e5ee76windows
Log Source
Windowssecurity
ProductWindows← raw: windows
Servicesecurity← raw: security
Detection Logic
Detection Logic13 selectors
detection:
    selection_1:
        EventID: 4656 # A handle to an object was requested.
        ObjectName|endswith: '\lsass.exe'
        AccessMask|contains:
            - '0x40'
            - '0x1400'
            # - '0x1000'  # minimum access requirements to query basic info from service
            - '0x100000'
            - '0x1410'    # car.2019-04-004
            - '0x1010'    # car.2019-04-004
            - '0x1438'    # car.2019-04-004
            - '0x143a'    # car.2019-04-004
            - '0x1418'    # car.2019-04-004
            - '0x1f0fff'
            - '0x1f1fff'
            - '0x1f2fff'
            - '0x1f3fff'
    selection_2:
        EventID: 4663 # An attempt was made to access an object
        ObjectName|endswith: '\lsass.exe'
        AccessList|contains:
            - '4484'
            - '4416'
    filter_main_specific:
        ProcessName|endswith:
            - '\csrss.exe'
            - '\GamingServices.exe'
            - '\lsm.exe'
            - '\MicrosoftEdgeUpdate.exe'
            - '\minionhost.exe'  # Cyberreason
            - '\MRT.exe'         # MS Malware Removal Tool
            - '\MsMpEng.exe'     # Defender
            - '\perfmon.exe'
            - '\procexp.exe'
            - '\procexp64.exe'
            - '\svchost.exe'
            - '\taskmgr.exe'
            - '\thor.exe'        # THOR
            - '\thor64.exe'      # THOR
            - '\vmtoolsd.exe'
            - '\VsTskMgr.exe'    # McAfee Enterprise
            - '\wininit.exe'
            - '\wmiprvse.exe'
            - 'RtkAudUService64' # https://medium.com/falconforce/the-curious-case-of-realtek-and-lsass-33fc0c8482ff
        ProcessName|contains:
            - ':\Program Files (x86)\'
            - ':\Program Files\'
            - ':\ProgramData\Microsoft\Windows Defender\Platform\'
            - ':\Windows\SysNative\'
            - ':\Windows\System32\'
            - ':\Windows\SysWow64\'
            - ':\Windows\Temp\asgard2-agent\'
    filter_main_generic:
        ProcessName|contains: ':\Program Files'  # too many false positives with legitimate AV and EDR solutions
    filter_main_exact:
        ProcessName|endswith:
            - ':\Windows\System32\taskhostw.exe'
            - ':\Windows\System32\msiexec.exe'
            - ':\Windows\CCM\CcmExec.exe'
    filter_main_sysmon:
        ProcessName|endswith: ':\Windows\Sysmon64.exe'
        AccessList|contains: '%%4484'
    filter_main_aurora:
        ProcessName|contains: ':\Windows\Temp\asgard2-agent-sc\aurora\'
        ProcessName|endswith: '\aurora-agent-64.exe'
        AccessList|contains: '%%4484'
    filter_main_scenarioengine:
        # Example: C:\a70de9569c3a5aa22184ef52a890177b\x64\SCENARIOENGINE.EXE
        ProcessName|endswith: '\x64\SCENARIOENGINE.EXE'
        AccessList|contains: '%%4484'
    filter_main_avira1:
        ProcessName|contains|all:
            - ':\Users\'
            - '\AppData\Local\Temp\is-'
        ProcessName|endswith: '\avira_system_speedup.tmp'
        AccessList|contains: '%%4484'
    filter_main_avira2:
        ProcessName|contains: ':\Windows\Temp\'
        ProcessName|endswith: '\avira_speedup_setup_update.tmp'
        AccessList|contains: '%%4484'
    filter_main_snmp:
        ProcessName|endswith: ':\Windows\System32\snmp.exe'
        AccessList|contains: '%%4484'
    filter_main_googleupdate:
        ProcessName|contains: ':\Windows\SystemTemp\'
        ProcessName|endswith: '\GoogleUpdate.exe'
        AccessList|contains: '%%4484'
    filter_optional_procmon:
        ProcessName|endswith:
            - '\procmon64.exe'
            - '\procmon.exe'
        AccessList|contains: '%%4484'
    condition: 1 of selection_* and not 1 of filter_main_* and not 1 of filter_optional_*
False Positives

Legitimate software accessing LSASS process for legitimate reason; update the whitelist with it

MITRE ATT&CK

CAR Analytics

2019-04-004 · CAR 2019-04-004
Rule Metadata
Rule ID
4a1b6da0-d94f-4fc3-98fc-2d9cb9e5ee76
Status
test
Level
medium
Type
Detection
Created
Fri Nov 01
Modified
Tue Dec 19
Path
rules/windows/builtin/security/win_security_susp_lsass_dump_generic.yml
Raw Tags
attack.credential-accesscar.2019-04-004attack.t1003.001
View on GitHub