Handle 32 bits PE for sideload/spawndll. Fix crash on unhandled Optio…

…nalHeader type
BishopFox · Oct 11, 2021 · 3a1ff3f · 3a1ff3f
1 parent 98aa4ed
commit 3a1ff3f
Showing 1 changed file with 14 additions and 2 deletions.
diff --git a/server/rpc/rpc-tasks.go b/server/rpc/rpc-tasks.go
@@ -316,7 +316,13 @@ func getExportOffsetFromFile(filepath string, exportName string) (funcOffset uin
 	}
 	defer handle.Close()
 	fpe, _ := pe.NewFile(handle)
-	exportDirectoryRVA := fpe.OptionalHeader.(*pe.OptionalHeader64).DataDirectory[pe.IMAGE_DIRECTORY_ENTRY_EXPORT].VirtualAddress
+	var exportDirectoryRVA uint32
+	switch (fpe.OptionalHeader).(type) {
+	case *pe.OptionalHeader32:
+		exportDirectoryRVA = fpe.OptionalHeader.(*pe.OptionalHeader32).DataDirectory[pe.IMAGE_DIRECTORY_ENTRY_EXPORT].VirtualAddress
+	case *pe.OptionalHeader64:
+		exportDirectoryRVA = fpe.OptionalHeader.(*pe.OptionalHeader64).DataDirectory[pe.IMAGE_DIRECTORY_ENTRY_EXPORT].VirtualAddress
+	}
 	var offset = rvaToFoa(exportDirectoryRVA, fpe)
 	exportDir := ExportDirectory{}
 	buff := &bytes.Buffer{}
@@ -350,7 +356,13 @@ func getExportOffsetFromMemory(rawData []byte, exportName string) (funcOffset ui
 		return 0, err
 	}
 
-	exportDirectoryRVA := fpe.OptionalHeader.(*pe.OptionalHeader64).DataDirectory[pe.IMAGE_DIRECTORY_ENTRY_EXPORT].VirtualAddress
+	var exportDirectoryRVA uint32
+	switch (fpe.OptionalHeader).(type) {
+	case *pe.OptionalHeader32:
+		exportDirectoryRVA = fpe.OptionalHeader.(*pe.OptionalHeader32).DataDirectory[pe.IMAGE_DIRECTORY_ENTRY_EXPORT].VirtualAddress
+	case *pe.OptionalHeader64:
+		exportDirectoryRVA = fpe.OptionalHeader.(*pe.OptionalHeader64).DataDirectory[pe.IMAGE_DIRECTORY_ENTRY_EXPORT].VirtualAddress
+	}
 	var offset = rvaToFoa(exportDirectoryRVA, fpe)
 	exportDir := ExportDirectory{}
 	buff := &bytes.Buffer{}