It is the exe for Symantec Installation Manager
You install Symantec Installation Manager in one of the following ways: •Download and install it from http://www.symantec.com.
You download it from the product page of the product that you want to install. All of the Symantec Management Platform products are listed at Business > Products > Products A-Z. When you select a Symantec Management Platform product, a Web page opens for that product. Every product's Web page has a Trialware link. The Trialware link takes you to the Software Download page. The Download button on the Software Download page, lets you download and run the EXE that installs Symantec Installation Manager. The name of the file is symantec_sim.exe.
•If the Symantec Managemnet Platform product is distributed on a CD, install it from the CD.
http://www.symantec.com/business/support/index?page=content&id=HOWTO9795