diff --git a/external/yara/CMakeLists.txt b/external/yara/CMakeLists.txt
index 94e037924..553ab41f2 100644
--- a/external/yara/CMakeLists.txt
+++ b/external/yara/CMakeLists.txt
@@ -96,7 +96,7 @@ set(LIBYARA_MODULES
 # Add mbedtls crypto wrappers
 add_custom_command(
         OUTPUT ${LIBYARA_SOURCE_PATH}/crypto.h
-        COMMAND ${CMAKE_COMMAND} -E copy ${CMAKE_CURRENT_SOURCE_DIR}/crypto_mbedtls.h ${LIBYARA_SOURCE_PATH}/crypto.h
+        COMMAND ${CMAKE_COMMAND} -E copy_if_different ${CMAKE_CURRENT_SOURCE_DIR}/crypto_mbedtls.h ${LIBYARA_SOURCE_PATH}/crypto.h
         MAIN_DEPENDENCY ${CMAKE_CURRENT_SOURCE_DIR}/crypto_mbedtls.h)
 add_compile_definitions("HAVE_MBEDTLS")