Oracle 11.2.0.3 was available for:

Oracle Database 11g Release 2 (11.2.0.3) is a relational database management system (RDBMS) designed to store, manage, and retrieve large amounts of data efficiently. It is a 64-bit database that supports various operating systems, including Windows, Linux, and Unix.

If you are a paying customer, you can open a Service Request (SR) requesting the physical ISO or a download link for 11.2.0.3. Oracle often retains these on internal servers as “media requests” for customers still under Extended or Sustaining Support.

Some organizations run 11.2.0.3 on fully isolated networks with no internet access, accepting the risk in exchange for application stability.