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.

This undated GCHQ presentation gives an overview of the agency’s use of hacking techniques, including an explanation of what it perceived the legal position to be at the time: see the Intercept