is it itself vulnerable at any point?
Yes,  source code for Symantec Endpoint Protection was stolen and published online
Symantec Endpoint Protection
In early 2012, source code for Symantec Endpoint Protection was stolen and published online. A hacker group called "The Lords of Dharmaraja" claimed credit, alleging the source code was stolen from Indian military intelligence. 
what is the current version of symantec endpoint protection Version 12.1.2 what does it refers to? It  is a security software suite that consists of anti-malware, intrusion prevention and firewall features for server and desktop computers can you state any one feature of it? In computing, a firewall is a network security system that monitors and controls incoming and outgoing network traffic based on predetermined security rules
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Symantec Endpoint Protection [SEP] Vulnerabilities
In early 2012, source code for Symantec Endpoint Protection was stolen and published online. A hacker group called "The Lords of Dharmaraja" claimed credit, alleging the source code was stolen from Indian military intelligence. The Indian government requires vendors to submit the source code of any computer program being sold to the government, to ensure that they are not being used for espionage. In July 2012, an update to Endpoint Protection caused compatibility issues, triggering a Blue Screen of Death on Windows XP machines running certain third-party file system drivers. In 2014, Offensive Security discovered an exploit in Symantec Endpoint Protection during a penetration test of a financial services organization.