The personally identifiable information of 850 Singapore military service members and Ministry of Defense staffers was compromised in what is being called a targeted and carefully planned attack on the MOD's I-net computer system.

The I-net breach was discovered earlier this month, but ministry officials reported no sensitive information was leaked, according to the Singapore Straits Times. The I-net system is used by troops and civilian MoD workers to access the internet for personal reasons and is not connected to the countries defense computer network.

The 850 people affected had their National Registration Identity Card numbers, telephone numbers and birth dates stolen. Upon detecting the breach the infected server was put offline and the vulnerability has since been patched.

Exactly how the system was breached was not revealed.