The company is M5 Network Security Pty Ltd., which has headquarters in Canberra, Australia, and is privately held.
"This acquisition enhances our ability to provide innovative, agile and proven cyber-security and communication solutions to Australian customers," said Wes Bush, Northrop Grumman chairman, chief executive officer and president.
The financial terms of the acquisition, which is subject to review by the Australian government, weren't disclosed. The transaction is expected to be completed this year.
"M5 Network Security remains committed to maintaining the highest level of performance and service for our customers," said Matthew Wilson, managing director, M5 Network Security.
"We expect that as part of Northrop Grumman, our customers also will benefit from the cyber-security leadership and extensive resources that Northrop Grumman can bring to M5 Network Security and its employees."