What is an S-2 or G-2?
In the U.S. Army, battalion and brigade units have a staff of officers that advises the executive and commanding officers about issues such as operations, security and intelligence, personnel and finance. Each of these staff officers is indicated by the letter “S” and a number. The S-2 officer is responsible for the unit’s intelligence operations and security. Though the specific duties of the S-2 might vary with the unit’s function (infantry, engineering, military police, etc.), all S-2s are responsible for acquiring and disseminating intelligence. At the battalion level, the S-2 officer usually holds the rank of first lieutenant or captain. At the brigade level, the S-2 is generally a major. (Source: https://careertrend.com/list-6692783-s2-army-officer-duties.html)
The G-2 is similar but at the Division and above level.
Many of these task are performed by Security Managers in the corporate world.