Known only as Daniel K, the hacker is now being sought for extradition to the UK where he also faces criminal charges.
The 29-year-old, who has only been named as Daniel K, received a suspended sentence of 20 months for attempted commercial computer sabotage.
He was wanted in Germany after roughly 900,000 consumer routers were knocked offline when he attempted to hijack control of them using a modified version of the Mirai botnet code.
The modified code subsequently spread around the internet, affecting a number of telecommunications companies globally.
Daniel K admitted carrying out the cyberattack last week in the face of a maximum sentence of 10 years, although German prosecutors asked for two years.
Speaking in court at the time, he described the attack as «the worst mistake of my life» and claimed that he had been paid £7,700 ($10,000) by a Liberian company that wanted him to develop a botnet to attack a competitor.
Deutsche Telekom said the attack caused about £1.7m (€2m) of damage and said it only ended after it advised its customers to disconnect their routers and restart them after a software update.
Daniel K, who was arrested at Luton airport earlier this year, now faces criminal charges in the UK where authorities are seeking his extradition.
