Threat Huntmediumtest

LSASS Access From Program In Potentially Suspicious Folder

Detects process access to LSASS memory with suspicious access flags and from a potentially suspicious folder

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Launch

Florian Roth (Nextron Systems)Created Sat Nov 27Updated Wed Dec 06fa34b441-961a-42fa-a100-ecc28c886725windows

Hunting Hypothesis

Log Source

WindowsProcess Access

ProductWindows← raw: windows

CategoryProcess Access← raw: process_access

Events when a process opens a handle to another process, commonly used for credential dumping via LSASS.

Detection Logic

detection:
    selection:
        TargetImage|endswith: '\lsass.exe'
        GrantedAccess|endswith:
            - '10'
            - '30'
            - '50'
            - '70'
            - '90'
            - 'B0'
            - 'D0'
            - 'F0'
            - '18'
            - '38'
            - '58'
            - '78'
            - '98'
            - 'B8'
            - 'D8'
            - 'F8'
            - '1A'
            - '3A'
            - '5A'
            - '7A'
            - '9A'
            - 'BA'
            - 'DA'
            - 'FA'
            - '0x14C2'  # https://github.com/b4rtik/ATPMiniDump/blob/76304f93b390af3bb66e4f451ca16562a479bdc9/ATPMiniDump/ATPMiniDump.c
            - 'FF'
        SourceImage|contains:
            - '\Temp\'
            - '\Users\Public\'
            - '\PerfLogs\'
            - '\AppData\'
            - '\Temporary'
    filter_optional_generic_appdata:
        SourceImage|contains|all:
            - ':\Users\'
            - '\AppData\Local\'
        SourceImage|endswith:
            - '\Microsoft VS Code\Code.exe'
            - '\software_reporter_tool.exe'
            - '\DropboxUpdate.exe'
            - '\MBAMInstallerService.exe'
            - '\WebexMTA.exe'
            - '\Meetings\WebexMTAV2.exe'
            - '\WebEx\WebexHost.exe'
            - '\JetBrains\Toolbox\bin\jetbrains-toolbox.exe'
        GrantedAccess: '0x410'
    filter_optional_dropbox_1:
        SourceImage|contains: ':\Windows\Temp\'
        SourceImage|endswith: '.tmp\DropboxUpdate.exe'
        GrantedAccess:
            - '0x410'
            - '0x1410'
    filter_optional_dropbox_2:
        SourceImage|contains|all:
            - ':\Users\'
            - '\AppData\Local\Temp\'
        SourceImage|endswith: '.tmp\DropboxUpdate.exe'
        GrantedAccess: '0x1410'
    filter_optional_dropbox_3:
        SourceImage|contains:
            - ':\Program Files (x86)\Dropbox\'
            - ':\Program Files\Dropbox\'
        SourceImage|endswith: '\DropboxUpdate.exe'
        GrantedAccess: '0x1410'
    filter_optional_nextron:
        SourceImage|contains:
            - ':\Windows\Temp\asgard2-agent\'
            - ':\Windows\Temp\asgard2-agent-sc\'
        SourceImage|endswith:
            - '\thor64.exe'
            - '\thor.exe'
            - '\aurora-agent-64.exe'
            - '\aurora-agent.exe'
        GrantedAccess:
            - '0x1fffff'
            - '0x1010'
            - '0x101010'
    filter_optional_ms_products:
        SourceImage|contains|all:
            - ':\Users\'
            - '\AppData\Local\Temp\'
            - '\vs_bootstrapper_'
        GrantedAccess: '0x1410'
    filter_optional_chrome_update:
        SourceImage|contains: ':\Program Files (x86)\Google\Temp\'
        SourceImage|endswith: '.tmp\GoogleUpdate.exe'
        GrantedAccess:
            - '0x410'
            - '0x1410'
    filter_optional_keybase:
        SourceImage|contains: ':\Users\'
        SourceImage|endswith: \AppData\Local\Keybase\keybase.exe
        GrantedAccess: '0x1fffff'
    filter_optional_avira:
        SourceImage|contains: '\AppData\Local\Temp\is-'
        SourceImage|endswith: '.tmp\avira_system_speedup.tmp'
        GrantedAccess: '0x1410'
    filter_optional_viberpc_updater:
        SourceImage|contains: '\AppData\Roaming\ViberPC\'
        SourceImage|endswith: '\updater.exe'
        TargetImage|endswith: '\winlogon.exe'
        GrantedAccess: '0x1fffff'
    filter_optional_adobe_arm_helper:
        SourceImage|contains:  # Example path: 'C:\Program Files (x86)\Common Files\Adobe\ARM\1.0\Temp\2092867405\AdobeARMHelper.exe'
            - ':\Program Files\Common Files\Adobe\ARM\'
            - ':\Program Files (x86)\Common Files\Adobe\ARM\'
        SourceImage|endswith: '\AdobeARMHelper.exe'
        GrantedAccess: '0x1410'
    condition: selection and not 1 of filter_optional_*