The Litecoin network is secured by its network of miners. Because it is a decentralized cryptocurrency, everyone can participate in the block validation process.
When it comes to the possibility of security breaches, people often think about 51% of attacks. Litecoin developers take security issues very seriously, and are known for not compromising on them. Thanks to its vast, decentralized network of participants, coupled with the efforts of its developers, LTC is unlikely to succumb to these types of malicious network attacks.