发布于2022年11月4日3年前 如何使用scemu安全地模拟Shellcode执行 关于scemuscemu是一款功能强大的Shellcode模拟工具，该工具支持x86 32位模拟仿真，可以帮助广大研究人员以安全的方式运行和分析Shellcode。功能介绍1、Rust安全，适用于恶意软件；2、所有依赖项基于Rust；3、速度运行快；4、每秒300万条指令；5、每秒打印100000条指令；6、iced-x86 rust反编译器提供支持；7、迭代检测器；8、内存和寄存器跟踪；9、代码颜色高亮显示；10、支持在某个时刻停止、分析和修改状态；11、实现了105条指令；12、实现了5个DLL的112个WinAPI；13、支持所有的Linux系统调用syscall；14、SEH链；15、向量异常处理程序；16、支持PEB、TEB结构；17、带有内存分配器；18、支持使用已知Payload测试；19、Metasploit Shellcode；20、Metasploit Encoder；21、Cobalt Strike；22、Shellgen；23、Guloader；工具下载广大研究人员可以使用下列命令将该项目源码克隆至本地：git clone https://github.com/sha0coder/scemu.git工具使用SCEMU 32bits emulator for Shellcodes 0.2.5 @sha0coder USAGE: scemu [FLAGS] [OPTIONS] FLAGS: -e, --endpoint 使用Tor或VPN与终端进行通信 -h, --help 输出帮助信息 -l, --loops 显示循环迭代 -m, --memory 跟踪所有的内存访问读取和写入行为 -n, --nocolors 无颜色输出打印 -r, --regs 打印每一步的寄存器值 -V, --version 打印版本信息 -v, --verbose -vv开启Verbose模式 OPTIONS: -b, --base <ADDRESS> 设置代码基址set base address for code -c, --console <NUMBER> 选择时间进行控制台信息审查 -C, --console_addr <ADDRESS> 检测到第一个eip = address时生成终端 -a, --entry <ADDRESS> Shellcode的入口点 -f, --filename <FILE> 设置Shellcode源码文件 -i, --inspect <DIRECTION> 监控内存，例如：-i 'dword ptr [ebp + 0x24] -M, --maps <PATH> 选择内存映射目录 -R, --reg <REGISTER> 跟踪指定的寄存器，包括值和内容 -s, --string <ADDRESS> 监控指定地址的字符串工具使用场景scemu模拟一个简单的Shellcode并检测execve()中断：我们选择某一行停止并检查内存：在Linux下模拟了将近两百万条GuLoader指令后，伪造cpuid和其他内容，便足以混淆调试器：API加载器的内存导出数据：工具默认提供了一些映射信息，我们也可以手动进行创建：模拟基于LdrLoadDLl()的Windows Shellcode，并输出信息：终端窗口支持查看和编辑CPU的当前状态：--- console --- =>h --- help --- q ...................... quit cls .................... clear screen h ...................... help s ...................... stack v ...................... vars r ...................... register show all r reg .................. show reg rc ..................... register change f ...................... show all flags fc ..................... clear all flags fz ..................... toggle flag zero fs ..................... toggle flag sign c ...................... continue ba ..................... breakpoint on address bi ..................... breakpoint on instruction number bmr .................... breakpoint on read memory bmw .................... breakpoint on write memory bc ..................... clear breakpoint n ...................... next instruction eip .................... change eip push ................... push dword to the stack pop .................... pop dword from stack fpu .................... fpu view md5 .................... check the md5 of a memory map seh .................... view SEH veh .................... view vectored execption pointer m ...................... memory maps ma ..................... memory allocs mc ..................... memory create map mn ..................... memory name of an address ml ..................... memory load file content to map mr ..................... memory read, speficy ie: dword ptr [esi] mw ..................... memory read, speficy ie: dword ptr [esi] and then: 1af md ..................... memory dump mrd .................... memory read dwords mds .................... memory dump string mdw .................... memory dump wide string mdd .................... memory dump to disk mt ..................... memory test ss ..................... search string sb ..................... search bytes sba .................... search bytes in all the maps ssa .................... search string in all the maps ll ..................... linked list walk d ...................... dissasemble dt ..................... dump structure enter .................. step intoCobalt Stike API加载器与Metasploit类似，模拟结果如下：Cobalt Strike API调用：Metasploit rshell API调用：Metasploit SGN编码器使用FPU来隐藏polymorfism：Metasploit shikata-ga-nai编码器：显示PEB结构信息：=>dt structure=>peb address=>0x7ffdf000 PEB { reserved1: [ 0x0, 0x0, ], being_debugged: 0x0, reserved2: 0x0, reserved3: [ 0xffffffff, 0x400000, ], ldr: 0x77647880, process_parameters: 0x2c1118, reserved4: [ 0x0, 0x2c0000, 0x77647380, ], alt_thunk_list_ptr: 0x0, reserved5: 0x0, reserved6: 0x6, reserved7: 0x773cd568, reserved8: 0x0, alt_thunk_list_ptr_32: 0x0, reserved9: [ 0x0, ...显示PEB_LDR_DATA结构：=>dt structure=>PEB_LDR_DATA address=>0x77647880 PebLdrData { length: 0x30, initializated: 0x1, sshandle: 0x0, in_load_order_module_list: ListEntry { flink: 0x2c18b8, blink: 0x2cff48, }, in_memory_order_module_list: ListEntry { flink: 0x2c18c0, blink: 0x2cff50, }, in_initialization_order_module_list: ListEntry { flink: 0x2c1958, blink: 0x2d00d0, }, entry_in_progress: ListEntry { flink: 0x0, blink: 0x0, }, } =>显示LDR_DATA_TABLE_ENTRY和第一个模块名称：=>dt structure=>LDR_DATA_TABLE_ENTRY address=>0x2c18c0 LdrDataTableEntry { reserved1: [ 0x2c1950, 0x77647894, ], in_memory_order_module_links: ListEntry { flink: 0x0, blink: 0x0, }, reserved2: [ 0x0, 0x400000, ], dll_base: 0x4014e0, entry_point: 0x1d000, reserved3: 0x40003e, full_dll_name: 0x2c1716, reserved4: [ 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, ], reserved5: [ 0x17440012, 0x4000002c, 0xffff0000, ], checksum: 0x1d6cffff, reserved6: 0xa640002c, time_date_stamp: 0xcdf27764, } =>恶意软件在异常中隐藏信息：3307726 0x4f9673: push ebp 3307727 0x4f9674: push edx 3307728 0x4f9675: push eax 3307729 0x4f9676: push ecx 3307730 0x4f9677: push ecx 3307731 0x4f9678: push 4F96F4h 3307732 0x4f967d: push dword ptr fs:[0] Reading SEH 0x0 ------- 3307733 0x4f9684: mov eax,[51068Ch] --- console --- =>检查异常结构：--- console --- =>r esp esp: 0x22de98 =>dt structure=>cppeh_record address=>0x22de98 CppEhRecord { old_esp: 0x0, exc_ptr: 0x4f96f4, next: 0xfffffffe, exception_handler: 0xfffffffe, scope_table: PScopeTableEntry { enclosing_level: 0x278, filter_func: 0x51068c, handler_func: 0x288, }, try_level: 0x288, } =>项目地址scemu：【GitHub传送门】本文作者：Alpha_h4ck
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