Malware
Malware (a portmanteau for malicious software) is any software intentionally designed to cause damage to a computer, server, client, or computer network. Malware does the damage after it is implanted or introduced in some way into a target's computer and can take the form of executable code, scripts, active content, and other software. The code is described as computer viruses, worms, Trojan horses, ransomware, spyware, adware, and scareware, among other terms. Malware has a malicious intent, acting against the interest of the computer user—and so does not include software that causes unintentional harm due to some deficiency, which is typically described as a software bug.
Regin (malware)
Symantec says that both it and Kaspersky identified the malware as "Backdoor. Regin". Most antivirus programs, including Kaspersky, (as of October 2015) do NOT identify the sample of Regin released by The Intercept as malware. On 9 March 2011 Microsoft added related entries to its Malware Encyclopedia; later two more variants, "Regin. B" and "Regin. C" were added. Microsoft appears to call the 64-bit variants of Regin "Prax. A" and "Prax. B". The Microsoft entries do not have any technical information. Both Kaspersky and Symantec have published white papers with information they learned about the malware.