This undated GCHQ reference document enumerates the processes and tools analysts use for computer network exploitation: see the Der Spiegel article The Digital Arms Race: NSA Preps America for Future Battle, 17 January 2015.

This page from GCHQ’s internal GCWiki provides a guide to the NSA’s XKeyScore tool: see the Der Spiegel article The NSA in Germany: Snowden’s Documents Available for Download, 18 June 2014.

This page from GCHQ’s internal GCWiki, last updated on 1 May 2012 documents progress in a variety of the agency’ projects: see Facing Data Deluge, Secret U.K. Spying Report Warned of Intelligence Failure, 7 June 2016.

This extract from a 2012 GCHQ document details progress in the operation against Belgian telecommunications company Belgacom in the first quarter of 2012: see the Intercept article Operation Socialist: The Inside Story of How British Spies Hacked Belgium’s Largest Telco, 13 December 2014.

This GCHQ presentation from 2011 provides the background to the agency’s hacking attack on Belgacom: see the Intercept article Operation Socialist: The Inside Story of How British Spies Hacked Belgium’s Largest Telco, 13 December 2014. gchq-mobile-networks-in-my-noc-world

These intenal NSA minutes from a meeting that took place on 8 June 2009 discuss GCSB activities and interoperability between NSA systems: see the New Zealand Herald article NZ’s spy reach stretches across globe, 11 March 2015.