This GCHQ application for warrant renewal from June 2008 shows that the agency has been engaged in the reverse engineering of commercial antivirus software for the purposes of facilitating its hacking operations: see the Intercept article Popular Security Software Came Under Relentless NSA and GCHQ Attacks, 22 June 2015.
This 9 September 2011 post from the NSA’s internal intranet, NSANet, is from the Ask Zelda! series of columns, which are popular within the agency. In this post, the NSA’s own agony aunt counsels agency employee Silenced in SID who is concerned about surveillance in the workplace: see the Intercept article The NSA Has An Advice Columnist. Seriously., 7 March 2014.