This NSA TURBULENCE presentation dated August 2009 explains the APEX method of combining passive with active methods to exfiltrate data from networks attacked: see the Der Spiegel article The Digital Arms Race: NSA Preps America for Future Battle, 17 January 2015.

This undated NSA presentation describes how to perform attacks against VPNs: see the Der Spiegel story Prying Eyes: Inside the NSA’s War on Internet Security, 28 December 2014.

This undated NSA presentation from the agency’s Information Technology Directorate, aimed at analysts, describes techniques for decrypting IPSec VPN traffic: see the Der Spiegel story Prying Eyes: Inside the NSA’s War on Internet Security, 28 December 2014.

This undated NSA presentation sets out the network-mapping tool Treasure Map, and supplies information on some of the agency’s collection access points: see the Intercept article New Zealand Launched Mass Surveillance Project While Publicly Denying It, 15 September 2014.

This 13 September 2010 presentation from the NSA’s OTP VPN Exploitation Team explains the work of the division: see the Der Spiegel story Prying Eyes: Inside the NSA’s War on Internet Security, 28 December 2014.

This NSA presentation dated 27 October 2009 outlines the use of intercepted IPSec VPN data within the agency: see the Der Spiegel story Prying Eyes: Inside the NSA’s War on Internet Security, 28 December 2014.

Slides from an NSA Turbulence presentation describe two of the agency’s specialised implants, aimed at compromising virtual private networks (VPNs) and online telephony (VOIP): see the Intercept article How the NSA Plans to Infect ‘Millions’ of Computers with Malware, 12 March 2014.

This undated NSA presentation, presented together with speaking notes, provides an introduction to the main cable access programmes facilitated by the agency’s corporate partners and specifies the relevant SIGADs: see the book No Place to Hide, 13 May 2014.

This undated NSA presentation describes the Spin 9 system for decrypting VPN data: see the Der Spiegel story Prying Eyes: Inside the NSA’s War on Internet Security, 28 December 2014.

This undated page from NSA’s internal WikiInfo describes VALIANTSURF “the coverterm for the development of Data Network Cipher (DNC) exploitation capabilities in TURMOIL”: see the Der Spiegel story Prying Eyes: Inside the NSA’s War on Internet Security, 28 December 2014.

This undated page from NSA’s internal WikiInfo describes some of the agency’s techniques for capturing IPSec Virtual Private Network (VPN) traffic: see the Der Spiegel story Prying Eyes: Inside the NSA’s War on Internet Security, 28 December 2014.

This undated presentation from NSA’s Network Analysis Center describes agency techniques for overcoming Virtual Private Networks (VPNs): see the Der Spiegel story Prying Eyes: Inside the NSA’s War on Internet Security, 28 December 2014.