A Windows host shows a suspicious registry change under the LSA hive. Review recent registry events to locate any new entries under Authentication Packages and determine the name of the DLL the attacker added.

DeviceRegistryEvents | where RegistryKey has "Control\\Lsa" | where RegistryValueName contains_cs "Authenticat" | where ActionType in ("RegistryValueSet", "RegistryKeyValueSet", "RegistryKeyWritten", "SetValue", "RegValueSet", "Modified", "Value Set") | project TimeGenerated, DeviceName, InitiatingProcessAccountName, InitiatingProcessFileName, RegistryKey, RegistryValueName, RegistryValueData | order by TimeGenerated desc

DeviceRegistryEvents | where RegistryKey has_any ('HKEY_LOCAL_MACHINE\\System\\CurrentControlSet\\Control\\Lsa', 'HKEY_LOCAL_MACHINE\\System\\ControlSet001\\Control\\Lsa') | where RegistryValueName == 'Authentication Packages' | project TimeGenerated, RegistryKey, RegistryValueName, RegistryValueData | order by TimeGenerated desc | where RegistryValueData contains '.dll' | summarize arg_max(TimeGenerated, *) by RegistryValueData

let lsaKeyRegex = @"(?i).*(\\system\\(currentcontrolset|controlset\d{3})\\control\\lsa)$"; let normalize = (s:string) { tolower(trim(" ;,\t\r\n", replace_regex(replace_regex(replace_regex(tostring(s), @"\u0000", ";"), @"[\r\n]+", ";"), @",", ";"))) }; DeviceRegistryEvents | where RegistryValueName =~ "Authentication Packages" | where RegistryKey matches regex lsaKeyRegex | extend OldRaw = tostring(PreviousRegistryValueData), NewRaw = tostring(RegistryValueData) | where isnotempty(NewRaw) | extend NewArr = split(normalize(NewRaw), ";") | extend OldArr = iif(isempty(OldRaw), dynamic([]), split(normalize(OldRaw), ";")) | extend AddedPackages = set_difference(NewArr, OldArr) | extend AddedPackages = set_difference(AddedPackages, dynamic([""])) | where array_length(AddedPackages) > 0 | project TimeGenerated, DeviceName, DeviceId, RegistryKey, RegistryValueName, AddedPackages, RegistryValueData = NewRaw, PreviousRegistryValueData = OldRaw, InitiatingProcessAccountDomain, InitiatingProcessAccountName, InitiatingProcessFileName, InitiatingProcessCommandLine, InitiatingProcessId, InitiatingProcessSHA256 | order by TimeGenerated desc

let regs = DeviceRegistryEvents | where RegistryKey contains_cs "Control\\Lsa" or RegistryKey contains_cs "CurrentControlSet\\Control\\Lsa" or RegistryKey contains_cs "HKLM\\SYSTEM\\CurrentControlSet\\Control\\Lsa" or RegistryKey contains_cs "\\Registry\\Machine\\System\\CurrentControlSet\\Control\\Lsa" | where tolower(tostring(RegistryValueName)) contains "authentication package" or tolower(tostring(RegistryValueName)) contains "auth package" or tolower(tostring(RegistryValueName)) contains "auth packages" | extend CurrRaw = tostring(RegistryValueData), PrevRaw = tostring(PreviousRegistryValueData) | extend CurrClean = trim(" ;", replace_regex(CurrRaw, @"\\x00+", ";")), PrevClean = trim(" ;", replace_regex(PrevRaw, @"\\x00+", ";")) | extend CurrList = split(CurrClean, ";"), PrevList = split(PrevClean, ";") | extend EventId = strcat(DeviceId, "|", tostring(TimeGenerated)) | project EventId, TimeGenerated, DeviceName, DeviceId, InitiatingProcessFileName, InitiatingProcessCommandLine, RegistryKey, RegistryValueName, CurrList, PrevList, ActionType, ReportId; let curr = regs | mv-expand Entry = CurrList to typeof(string) | extend Entry = trim(" \"\n\r\t", Entry) | where Entry != "" | project EventId, TimeGenerated, DeviceName, DeviceId, InitiatingProcessFileName, InitiatingProcessCommandLine, RegistryKey, RegistryValueName, Entry; let prev = regs | mv-expand Entry = PrevList to typeof(string) | extend Entry = trim(" \"\n\r\t", Entry) | where Entry != "" | project EventId, Entry; curr | join kind=leftanti (prev) on EventId, Entry | extend DLL = tostring(Entry) | where tolower(DLL) endswith ".dll" | summarize FirstSeen=min(TimeGenerated), LastSeen=max(TimeGenerated), Devices=make_set(DeviceName), DeviceIds=make_set(DeviceId), InitiatingProcesses=make_set(InitiatingProcessFileName), InitiatingCommands=make_set(InitiatingProcessCommandLine), RegistryKeys=make_set(RegistryKey), Events=make_set(EventId) by DLL, RegistryValueName | order by LastSeen desc | project DLL, RegistryValueName, FirstSeen, LastSeen, Devices, DeviceIds, InitiatingProcesses, InitiatingCommands, RegistryKeys, Events

// Search for recent LSA registry changes (Authentication Packages) DeviceRegistryEvents | where TimeGenerated >= ago(7d) // remove or adjust if caller sets timerange externally | where RegistryKey has_cs "CurrentControlSet\\Control\\Lsa" or RegistryKey has_cs "\\Control\\Lsa" or RegistryKey has_cs "\\Lsa" | where tolower(RegistryValueName) has "authentication" or tolower(RegistryValueName) has "authenticationpackages" or tolower(RegistryValueName) has "authentication packages" or tolower(RegistryValueName) has "security packages" or tolower(RegistryValueName) has "securitypackages" | where ActionType has_any ("SetValue", "Create", "Set", "ValueSet", "RegistryValueSet", "Modify", "Modified", "Update") | extend LsaKey = RegistryKey, ValueName = RegistryValueName, ValueDataStr = tostring(RegistryValueData), PrevValue = tostring(PreviousRegistryValueData) | extend ValueDataClean = replace_regex(ValueDataStr, "[\r\n\t]+", " ") | mv-expand entry = split(ValueDataClean, ";") | mv-expand entry = split(entry, ",") | mv-expand entry = split(entry, " ") | extend entry = trim(' \"', tostring(entry)) | where entry != "" | extend entryLower = tolower(entry) | where entryLower endswith ".dll" or entryLower contains ".dll" | summarize FirstSeen = min(TimeGenerated), LastSeen = max(TimeGenerated), Count = count(), ExampleAction = any(ActionType), ExampleProcess = any(InitiatingProcessFileName), ExampleCmd = any(InitiatingProcessCommandLine), PrevExample = any(PrevValue) by DeviceName, DeviceId, LsaKey, ValueName, AddedDll = entry | order by LastSeen desc // Enrich with file events where possible | join kind=leftouter ( DeviceFileEvents | project FileTime=TimeGenerated, DeviceId, FileName, FolderPath, FileFullPath = strcat(FolderPath, "\\", FileName), FileEventCmd=InitiatingProcessCommandLine ) on DeviceId | where AddedDll contains tolower(FileName) or tolower(FileFullPath) contains tolower(AddedDll) or tolower(AddedDll) contains tolower(FileName) | project DeviceName, DeviceId, LsaKey, ValueName, AddedDll, FirstSeen, LastSeen, Count, ExampleAction, ExampleProcess, ExampleCmd, FileTime, FileFullPath, FileName, FileEventCmd | order by LastSeen desc

DeviceRegistryEvents | where ActionType in ("SetValue", "Create", "Update", "Delete", "RegistryValueSet") | where TimeGenerated >= ago(30d) | extend rk = tolower(tostring(RegistryKey)), rvn = tolower(tostring(RegistryValueName)), rvd = tostring(RegistryValueData), prev_rvd = tostring(PreviousRegistryValueData) // Focus on the LSA path or the Authentication Packages value name | where (rk contains "currentcontrolset" and rk contains "control" and rk contains "lsa") or rvn contains "authentication packages" or rvn contains "authenticationpackages" | where isnotempty(rvd) or isnotempty(rvn) // Extract DLL names from value data or value name. Pattern allows backslashes and drive letters. | extend dll_from_data = extract(@"([A-Za-z0-9_\\:\\\.\-]+\.dll)", 1, rvd) | extend dll_from_name = extract(@"([A-Za-z0-9_\\:\\\.\-]+\.dll)", 1, rvn) | extend AddedDLL = tolower(coalesce(dll_from_data, dll_from_name)) | where isnotempty(AddedDLL) // If previous value exists and already contained the DLL, it's not a new addition | extend prev_contains = iff(isnotempty(prev_rvd) and tolower(prev_rvd) contains AddedDLL, true, false) | where prev_contains == false // Keep the most recent record per device and DLL | summarize arg_max(TimeGenerated, *) by DeviceId, AddedDLL | project TimeGenerated, DeviceName, DeviceId, AddedDLL, RegistryKey, RegistryValueName, RegistryValueType, RegistryValueData, PreviousRegistryValueData, InitiatingProcessAccountName, InitiatingProcessFileName, InitiatingProcessCommandLine, ActionType | order by TimeGenerated desc

DeviceRegistryEvents | where RegistryKey has "\\Control\\Lsa" | where RegistryValueName =~ "Authentication Packages" | where ActionType in ("RegistryValueSet", "RegistryValueCreated", "RegistryValueModified") | project TimeGenerated, DeviceName, ActionType, RegistryKey, RegistryValueName, RegistryValueData, PreviousRegistryValueData, InitiatingProcessAccountName, InitiatingProcessCommandLine | order by TimeGenerated desc