Georgios (George) V. Magklaras (born in Agrinio, Greece) (Greek: Γεώργιος Μαγκλάρας ) is a computer scientist working as a Senior Computer Systems Engineer at the University of Oslo, in Norway.
 He is an information security researcher and developed methods in the field of insider IT misuse detection and prediction.
 He is also an active systems administrator information security consultant and Information Technology practitioner working with High Performance Computing, especially in the fields of Life Sciences and Bioinformatics applications.
 He has been a strong advocate of Linux, Open Source tools and the Perl programming language and has given a series of lectures internationally in the fields of Intrusion Detection Systems, Digital Forensics, Bioinformatics, Computer Programming and Systems Administration.
Michael Fisher (30 October 1946 – 7 January 2015) was a British solicitor, best known for his work representing those accused of terrorist offences during The Troubles in Northern Ireland.
Kristina Vladimirovna Svechinskaya (Russian: Кристина Владимировна Свечинская , born February 16, 1989) is a former Russian money mule hacker.
 A student of the New York University, in 2010 she was accused of a plot to defraud several British and U.S. banks of sizeable sums and usage of false passports.
 According to charges, Svechinskaya used Zeus trojan horse to attack thousands of bank accounts and opened at least five accounts in Bank of America and Wachovia, which received $35,000 (£22,000) of money theft.
 It is estimated that with nine other people Svechinskaya had skimmed $3 million in total.
 Svechinskaya was dubbed by the media "the world's sexiest computer hacker" for her raunchy, but casual appearance and was compared to Anna Chapman.
 The upcoming Russian film "Botnet" is partially based on Svechinskaya's story.
Clifford Paul "Cliff" Stoll (born June 4, 1950) is an American astronomer, author and teacher.
 He is best known for his investigation in 1986, while working as a systems administrator at the Lawrence Berkeley National Laboratory, that led to the capture of hacker Markus Hess, and for Stoll's subsequent book, "The Cuckoo's Egg", in which he details the investigation.
Karen Elizabeth Todner (born April 1962), is a British solicitor and author.
 She has appeared on television, radio and written articles for newspapers on legal topics.
 She specialises in international criminal law and human rights and, in this capacity, has represented clients taking cases to The House of Lords and European Court of Human Rights.
 Her clients include Ryan Cleary allegedly linked with LulzSec, Gary McKinnon known as the "Pentagon Hacker", and Lauri Love.
Marko Calasan (Macedonian: Марко Чаласан) (born 24 July 2000) is a Macedonian computer systems prodigy.
 He is noted for being the youngest certified computer systems administrator at the age of eight and the youngest certified computers systems engineer at the age of nine.
Albert Gonzalez (born 1981) is an American computer hacker and computer criminal who is accused of masterminding the combined credit card theft and subsequent reselling of more than 170 million card and ATM numbers from 2005 through 2007—the biggest such fraud in history.
 Gonzalez and his accomplices used SQL injection to deploy backdoors on several corporate systems in order to launch packet sniffing (specifically, ARP Spoofing) attacks which allowed him to steal computer data from internal corporate networks.
Denis Periša (born July 23, 1983) is a political activist, whistle blower and computer hacker from Šibenik, Croatia.
 He was convicted and criminally charged in September 1999.
 He was forbidden to use computer systems or internet for hacking e-mail of politician Veselin Pejnović and planting backdoor to his network.
 He founded the computer security website Jezgra.org in 1997 that is still active today.
 Founder of ŠI-WIFI wireless organization for his town in late 2005.
 Later in his life he became politically involved and was accused but never proven that he was working with local police and Croatian Democratic Union (HDZ).
 Denis is also a DJ, a photographer and recently a writer writing book called "My first suicide".
Dennis M. Moran (1982–April 14, 2013), also known by his alias Coolio, was an American computer hacker from Wolfeboro, New Hampshire, who was accused in February 2000 of a series of denial-of-service attacks that shut down some of the most popular websites on the Internet.
 He was later arrested and pleaded guilty to defacing the websites of DARE and RSA Security, as well as unauthorized access of the U.S. Army and Air Force computer systems at four military bases.
Gary McKinnon (born 10 February 1966) is a Scottish systems administrator and hacker who was accused in 2002 of perpetrating the "biggest military computer hack of all time," although McKinnon himself states that he was merely looking for evidence of free energy suppression and a cover-up of UFO activity and other technologies potentially useful to the public.
 On 16 October 2012, after a series of legal proceedings in Britain, Home Secretary Theresa May withdrew her extradition order to the United States.

Question: Karen Elizabeth Todner (born April 1962), is a British solicitor and author, Her clients include which  Scottish systems administrator and hacker who was accused in 2002 of perpetrating the "biggest military computer hack of all time", known as the "Pentagon Hacker"?
Answer: Gary McKinnon