scanner.cpp

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#include "scanner.h"
 
#include <sstream>
#include <fstream>
#include <string>
#include <locale>
#include <codecvt>
 
#include <tlhelp32.h>
 
#include "../utils/format_util.h"
#include "../utils/path_converter.h"
#include "../utils/workingset_enum.h"
#include "../utils/modules_enum.h"
#include "../utils/process_privilege.h"
#include "../utils/process_util.h"
 
#include "headers_scanner.h"
#include "code_scanner.h"
#include "iat_scanner.h"
#include "workingset_scanner.h"
#include "mapping_scanner.h"
#include "hook_targets_resolver.h"
#include "thread_scanner.h"
 
using namespace pesieve;
using namespace pesieve::util;
 
namespace pesieve {
 
    bool validate_param_str(PARAM_STRING& strparam)
    {
        if (!strparam.buffer || strparam.length == 0) {
            return false;
        }
        if (IsBadReadPtr(strparam.buffer, strparam.length)) {
            return false;
        }
        return true;
    }
 
    namespace util {
 
        void print_scantime(std::stringstream& stream, size_t timeInMs)
        {
            float seconds = ((float)timeInMs / 1000);
            float minutes = ((float)timeInMs / 60000);
            stream << std::dec << timeInMs << " ms.";
            if (seconds > 0.5) {
                stream << " = " << seconds << " sec.";
            }
            if (minutes > 0.5) {
                stream << " = " << minutes << " min.";
            }
        }
 
    }; // namespace util
 
    void print_scan_time(const char* scanned_element, size_t total_time)
    {
        std::stringstream ss;
        ss << "[*] "<< scanned_element << " scanned in ";
        util::print_scantime(ss, total_time);
        std::cout << ss.str() << std::endl;
    }
 
    bool is_running(HANDLE processHandle)
    {
        DWORD exitCode = 0;
        if (GetExitCodeProcess(processHandle, &exitCode)) {
            if (exitCode != STILL_ACTIVE) {
#ifdef _DEBUG
                std::cerr << "Process terminated, exit = " << std::dec << exitCode << "\n";
#endif
                return false; //process terminated, discontinue the scan
            }
        }
        return true;
    }
};
 
pesieve::ProcessScanner::ProcessScanner(HANDLE procHndl, bool is_reflection, pesieve::t_params _args)
    : processHandle(procHndl), isDEP(false), isReflection(is_reflection),
    args(_args)
{
    symbols.InitSymbols(this->processHandle);
    if (validate_param_str(args.modules_ignored)) {
        pesieve::util::string_to_list(args.modules_ignored.buffer, PARAM_LIST_SEPARATOR, ignoredModules);
    }
}
 
t_scan_status pesieve::ProcessScanner::scanForHollows(HANDLE processHandle, ModuleData& modData, RemoteModuleData &remoteModData, ProcessScanReport& process_report)
{
    BOOL isWow64 = FALSE;
#ifdef _WIN64
    is_process_wow64(processHandle, &isWow64);
#endif
    HeadersScanner scanner(processHandle, modData, remoteModData);
    HeadersScanReport *scan_report = scanner.scanRemote();
    if (!scan_report) {
        return SCAN_ERROR;
    }
    
    if (scan_report->archMismatch && isWow64) {
#ifdef _DEBUG
        std::cout << "Arch mismatch, reloading..." << std::endl;
#endif
        if (modData.reloadWow64()) {
            delete scan_report; // delete previous report
            scan_report = scanner.scanRemote();
        }
    }
    scan_report->moduleFile = modData.szModName;
    scan_report->isInPEB = modData.isModuleInPEBList();
 
    t_scan_status is_replaced = ModuleScanReport::get_scan_status(scan_report);
    if (is_replaced && !scan_report->isHdrReplaced()) {
        is_replaced = SCAN_NOT_SUSPICIOUS;
    }
    process_report.appendReport(scan_report);
    return is_replaced;
}
 
t_scan_status pesieve::ProcessScanner::scanForIATHooks(HANDLE processHandle, ModuleData& modData, RemoteModuleData &remoteModData, ProcessScanReport& process_report, t_iat_scan_mode filter)
{
    const peconv::ExportsMapper *expMap = process_report.exportsMap;
    if (!expMap) {
        return SCAN_ERROR;
    }
 
    if (process_report.isModuleReplaced(modData.moduleHandle)) {
#ifdef _DEBUG
        std::cout << "Cannot scan replaced module for IAT hooks!\n";
#endif
        return SCAN_ERROR;
    }
    IATScanner scanner(processHandle, modData, remoteModData, *expMap, process_report.modulesInfo, filter);
    IATScanReport *scan_report = scanner.scanRemote();
    if (!scan_report) {
        return SCAN_ERROR;
    }
    t_scan_status scan_res = ModuleScanReport::get_scan_status(scan_report);
    scan_report->moduleFile = modData.szModName;
    process_report.appendReport(scan_report);
    return scan_res;
}
 
t_scan_status pesieve::ProcessScanner::scanForHooks(HANDLE processHandle, ModuleData& modData, RemoteModuleData &remoteModData, ProcessScanReport& process_report, bool scan_data, bool scan_inaccessible)
{
    CodeScanner scanner(processHandle, modData, remoteModData);
    scanner.setScanData(scan_data);
    scanner.setScanInaccessible(scan_inaccessible);
    CodeScanReport *scan_report = scanner.scanRemote();
    if (!scan_report) {
        return SCAN_ERROR;
    }
    t_scan_status is_hooked = ModuleScanReport::get_scan_status(scan_report);
 
    scan_report->moduleFile = modData.szModName;
    process_report.appendReport(scan_report);
    return is_hooked;
}
 
bool pesieve::ProcessScanner::resolveHooksTargets(ProcessScanReport& process_report)
{
    HookTargetResolver hookResolver(process_report);
    std::set<ModuleScanReport*> &code_reports = process_report.reportsByType[ProcessScanReport::REPORT_CODE_SCAN];
    size_t resolved_count = hookResolver.resolveAllHooks(code_reports);
    return (resolved_count > 0);
}
 
inline bool set_non_suspicious(const std::set<ModuleScanReport*> &scan_reports, bool dnet_modules_only)
{
    bool is_set = false;
    std::set<ModuleScanReport*>::iterator itr;
    for (itr = scan_reports.begin(); itr != scan_reports.end(); ++itr) {
        ModuleScanReport* report = *itr;
        if (!report) {
            //this should never happen
            continue;
        }
        if (dnet_modules_only && !report->isDotNetModule) {
            continue;
        }
        if (report->status == SCAN_SUSPICIOUS) {
            report->status = SCAN_NOT_SUSPICIOUS;
            is_set = true;
        }
    }
    return is_set;
}
 
bool pesieve::ProcessScanner::filterDotNetReport(ProcessScanReport& process_report)
{
    if (!process_report.isManaged // Not a .NET process
        || this->args.dotnet_policy == pesieve::PE_DNET_NONE) // .NET policy not set
    {
        return false; // no filtering needed
    }
    bool is_set = false;
    if (this->args.dotnet_policy == pesieve::PE_DNET_SKIP_MAPPING
        || this->args.dotnet_policy == pesieve::PE_DNET_SKIP_ALL)
    {
        // set hook modules as not suspicious
        const std::set<ModuleScanReport*> &reports = process_report.reportsByType[ProcessScanReport::REPORT_MAPPING_SCAN];
        is_set = set_non_suspicious(reports, true);
    }
    if (this->args.dotnet_policy == pesieve::PE_DNET_SKIP_HOOKS
        || this->args.dotnet_policy == pesieve::PE_DNET_SKIP_ALL)
    {
        // set hook modules as not suspicious
        const std::set<ModuleScanReport*> &reports = process_report.reportsByType[ProcessScanReport::REPORT_CODE_SCAN];
        is_set = set_non_suspicious(reports, false);
    }
    if (this->args.dotnet_policy == pesieve::PE_DNET_SKIP_SHC
        || this->args.dotnet_policy == pesieve::PE_DNET_SKIP_ALL)
    {
        // set shellcodes detected by mempage scan as not suspicious
        const std::set<ModuleScanReport*> &reports = process_report.reportsByType[ProcessScanReport::REPORT_MEMPAGE_SCAN];
        const bool is_set1 = set_non_suspicious(reports, false);
 
        // set shellcodes detected by thread scan as not-suspicious
        const std::set<ModuleScanReport*>& reports2 = process_report.reportsByType[ProcessScanReport::REPORT_THREADS_SCAN];
        const bool is_set2 = set_non_suspicious(reports2, false);
        is_set = is_set1 || is_set2;
    }
    return is_set;
}
 
ProcessScanReport* pesieve::ProcessScanner::scanRemote()
{
    this->isDEP = is_DEP_enabled(this->processHandle);
 
    const bool is_64bit = pesieve::util::is_process_64bit(this->processHandle);
 
    ProcessScanReport *pReport = new ProcessScanReport(this->args.pid, is_64bit, this->isReflection, &this->args);
 
    char image_buf[MAX_PATH] = { 0 };
    GetProcessImageFileNameA(this->processHandle, image_buf, MAX_PATH);
    pReport->mainImagePath = device_path_to_win32_path(image_buf);
 
    std::stringstream errorsStr;
 
    // scan modules
    size_t modulesScanned = 0;
    try {
        modulesScanned = scanModules(*pReport);
    } catch (std::exception &e) {
        modulesScanned = 0;
        errorsStr << e.what();
    }
 
    // scan working set
    size_t regionsScanned = 0;
    try {
        regionsScanned = scanWorkingSet(*pReport);
    } catch (std::exception &e) {
        regionsScanned = 0;
        errorsStr << e.what();
    }
 
    // scan IATs
    size_t iatsScanned = 0;
    if (args.iat) {
        try {
            iatsScanned = scanModulesIATs(*pReport);
        }
        catch (std::exception& e) {
            iatsScanned = 0;
            errorsStr << e.what();
        }
    }
 
    // scan threads
    size_t threadsScanned = 0;
    if (args.threads) {
        try {
            threadsScanned = scanThreads(*pReport);
        }
        catch (std::exception& e) {
            threadsScanned = 0;
            errorsStr << e.what();
        }
    }
 
    // throw error only if none of the scans was successful
    if (!modulesScanned && !iatsScanned && !regionsScanned && !threadsScanned) {
        throw std::runtime_error(errorsStr.str());
    }
    //post-process hooks
    resolveHooksTargets(*pReport);
 
    //post-process detection reports according to the .NET policy
    filterDotNetReport(*pReport);
    return pReport;
}
 
size_t pesieve::ProcessScanner::scanWorkingSet(ProcessScanReport &pReport) //throws exceptions
{
    if (!util::count_workingset_entries(this->processHandle)) {
        throw std::runtime_error("Could not query the working set. ");
        return 0;
    }
    process_details proc_details(this->isReflection, this->isDEP);
 
    DWORD start_tick = GetTickCount();
    std::set<mem_region_info> region_bases;
    size_t pages_count = util::enum_workingset(processHandle, region_bases);
    if (!args.quiet) {
        std::cout << "Scanning workingset: " << std::dec << pages_count << " memory regions." << std::endl;
    }
    size_t counter = 0;
    //now scan all the nodes:
 
    for (auto set_itr = region_bases.begin(); set_itr != region_bases.end() && is_running(this->processHandle); ++set_itr, ++counter) {
        const mem_region_info region = *set_itr;
 
        WorkingSetScanner scanner(this->processHandle, proc_details, region, this->args, pReport);
        WorkingSetScanReport *my_report = scanner.scanRemote();
        if (!my_report) {
            continue;
        }
        my_report->is_listed_module = pReport.hasModule((ULONGLONG) my_report->module);
        // this is a code section inside a PE file that was already detected
        if (!my_report->has_pe 
            && (pReport.hasModuleContaining((ULONGLONG)my_report->module, my_report->moduleSize))
            )
        {
            my_report->status = SCAN_NOT_SUSPICIOUS;
        }
 
        pReport.appendReport(my_report);
    }
    if (!args.quiet) {
        const DWORD total_time = GetTickCount() - start_tick;
        print_scan_time("Workingset", total_time);
    }
    return counter;
}
 
ModuleScanReport* pesieve::ProcessScanner::scanForMappingMismatch(ModuleData& modData, ProcessScanReport& process_report)
{
    MappingScanner scanner(processHandle, modData);
    MappingScanReport *scan_report = scanner.scanRemote();
 
    process_report.appendReport(scan_report);
    return scan_report;
}
 
size_t pesieve::ProcessScanner::scanModules(ProcessScanReport &pReport)  //throws exceptions
{
    HMODULE hMods[1024] = { 0 };
    const size_t modules_count = enum_modules(this->processHandle, hMods, sizeof(hMods), LIST_MODULES_ALL);
    if (modules_count == 0) {
        return 0;
    }
    if (args.imprec_mode != PE_IMPREC_NONE || args.iat != pesieve::PE_IATS_NONE) {
        pReport.exportsMap = new peconv::ExportsMapper();
    }
 
    size_t counter = 0;
    for (counter = 0; counter < modules_count && is_running(this->processHandle); counter++) {
        if (processHandle == nullptr) break;
        const HMODULE module_base = hMods[counter];
        //load module from file:
        ModuleData modData(processHandle, module_base, true, args.use_cache);
        ModuleScanReport *mappingScanReport = this->scanForMappingMismatch(modData, pReport);
 
        //load the original file to make the comparisons:
        if (!modData.loadOriginal()) {
            if (!args.quiet) {
                std::cout << "[!][" << args.pid << "] Suspicious: could not read the module file!" << std::endl;
            }
            //make a report that finding original module was not possible
            pReport.appendReport(new UnreachableModuleReport(module_base, 0, modData.szModName));
            continue;
        }
        if (modData.isDotNet()) {
            // the process contains at least one .NET module. Treat it as managed process:
            pReport.isManaged = true;
        }
        // Don't scan modules that are in the ignore list
        const std::string plainName = peconv::get_file_name(modData.szModName);
        if (is_in_list(plainName, this->ignoredModules)) {
            // ...but add such modules to the exports lookup:
            if (pReport.exportsMap) {
                pReport.exportsMap->add_to_lookup(modData.szModName, (HMODULE)modData.original_module, (ULONGLONG)modData.moduleHandle);
            }
            if (!args.quiet) {
                std::cout << "[*] Skipping ignored: " << std::hex << (ULONGLONG)modData.moduleHandle << " : " << modData.szModName << std::endl;
            }
            pReport.appendReport(new SkippedModuleReport(modData.moduleHandle, modData.original_size, modData.szModName));
            continue;
        }
 
        if (!args.quiet) {
            std::cout << "[*] Scanning: " << modData.szModName;
            if (modData.isDotNet()) {
                std::cout << " (.NET) ";
            }
            std::cout << std::endl;
        }
        //load data about the remote module
        RemoteModuleData remoteModData(processHandle, this->isReflection, module_base);
        if (!remoteModData.isInitialized()) {
            if (!is_running(processHandle)) break;
            pReport.appendReport(new MalformedHeaderReport(module_base, 0, modData.szModName));
            continue;
        }
        t_scan_status is_hollowed = scanForHollows(processHandle, modData, remoteModData, pReport);
        if (is_hollowed == SCAN_ERROR) {
            continue;
        }
        if (is_hollowed == SCAN_NOT_SUSPICIOUS) {
            //if the content does not differ, ignore the different name of the mapped file
            mappingScanReport->status = SCAN_NOT_SUSPICIOUS;
        }
 
        // the module is not hollowed, so we can add it to the exports lookup:
        if (pReport.exportsMap) {
            pReport.exportsMap->add_to_lookup(modData.szModName, (HMODULE) modData.original_module, (ULONGLONG) modData.moduleHandle);
        }
 
        if (!args.no_hooks //if hooks not disabled
            && (is_hollowed == SCAN_NOT_SUSPICIOUS) // and process is not hollowed
            ) 
        {
            const bool scan_data = ((this->args.data >= pesieve::PE_DATA_SCAN_ALWAYS) && (this->args.data != pesieve::PE_DATA_SCAN_INACCESSIBLE_ONLY))
                || (!this->isDEP && (this->args.data == pesieve::PE_DATA_SCAN_NO_DEP));
            
            const bool scan_inaccessible = (this->isReflection && (this->args.data >= PE_DATA_SCAN_INACCESSIBLE));
            scanForHooks(processHandle, modData, remoteModData, pReport, scan_data, scan_inaccessible);
        }
    }
    return counter;
}
 
size_t pesieve::ProcessScanner::scanModulesIATs(ProcessScanReport &pReport) //throws exceptions
{
    if (!pReport.exportsMap) {
        return 0; // this feature cannot work without Exports Map
    }
    HMODULE hMods[1024];
    const size_t modules_count = enum_modules(this->processHandle, hMods, sizeof(hMods), LIST_MODULES_ALL);
    if (modules_count == 0) {
        return 0;
    }
    if (!args.quiet) {
        std::cout << "Scanning for IAT hooks: " << modules_count << " modules." << std::endl;
    }
    DWORD start_tick = GetTickCount();
    size_t counter = 0;
    for (counter = 0; counter < modules_count && is_running(this->processHandle); counter++) {
        if (!processHandle) break; // this should never happen
 
        const HMODULE module_base = hMods[counter];
        //load module from file:
        ModuleData modData(processHandle, module_base, true, args.use_cache);
 
        // Don't scan modules that are in the ignore list
        std::string plainName = peconv::get_file_name(modData.szModName);
        if (is_in_list(plainName, this->ignoredModules)) {
            continue;
        }
 
        //load data about the remote module
        RemoteModuleData remoteModData(processHandle, this->isReflection, module_base);
        if (remoteModData.isInitialized() == false) {
            //make a report that initializing remote module was not possible
            pReport.appendReport(new MalformedHeaderReport(module_base, 0, modData.szModName));
            continue;
        }
 
        // do the IAT scan:
        scanForIATHooks(processHandle, modData, remoteModData, pReport, this->args.iat);
    }
    if (!args.quiet) {
        const DWORD total_time = GetTickCount() - start_tick;
        print_scan_time("IATs", total_time);
    }
    return counter;
}
 
size_t pesieve::ProcessScanner::scanThreads(ProcessScanReport& pReport) //throws exceptions
{
    if (!this->symbols.IsInitialized()) {
        if (!args.quiet) {
            std::cerr << "[-] Failed to initialize symbols!\n";
        }
        return 0;
    }
 
    const DWORD pid = pReport.pid; //original PID, not a reflection!
 
    const bool is_64bit = pesieve::util::is_process_64bit(this->processHandle);
#ifndef _WIN64
    if (is_64bit) return 0;
#endif
 
    if (!args.quiet) {
        std::cout << "Scanning threads." << std::endl;
    }
    DWORD start_tick = GetTickCount();
 
    std::map<DWORD, thread_info> threads_info;
    if (!pesieve::util::fetch_threads_info(pid, threads_info)) { //extended info, but doesn't work on old Windows...
 
        if (!pesieve::util::fetch_threads_by_snapshot(pid, threads_info)) { // works on old Windows, but gives less data..
 
            if (!args.quiet) {
                std::cerr << "[-] Failed enumerating threads." << std::endl;
            }
            return 0;
        }
    }
    if (!pesieve::util::query_threads_details(threads_info)) {
        if (!args.quiet) {
            std::cout << "[-] Failed quering thread details." << std::endl;
        }
    }
 
    for (auto itr = threads_info.begin(); itr != threads_info.end() && is_running(this->processHandle); ++itr) {
        const thread_info &info = itr->second;
        
        ThreadScanner scanner(this->processHandle, this->isReflection, info,  pReport.modulesInfo, pReport.exportsMap, &symbols);
        ThreadScanReport* report = scanner.scanRemote();
        pReport.appendReport(report);
    }
    if (!args.quiet) {
        const DWORD total_time = GetTickCount() - start_tick;
        print_scan_time("Threads", total_time);
    }
    return 0;
}