Ryuk ransomware attackers targeted the T-system in November 2019.
The attackers left the ransom note in HTML on the company's computers and several files were added the .RYK extension that is specific to Ryuk.
The note had a contact email address and instructions for paying the ransom.
Source: https://www.bleepingcomputer.com/news/security/ryuk-ransomware-is-making-victims-left-and-right/
TPRM report: https://scoringcyber.rankiteo.com/company/tsystem
"id": "the20459222",
"linkid": "tsystem",
"type": "Ransomware",
"date": "11/2019",
"severity": "100",
"impact": "5",
"explanation": "Attack threatening the organization's existence"{'affected_entities': [{'name': 'T-System', 'type': 'Company'}],
'date_detected': 'November 2019',
'description': 'Ryuk ransomware attackers targeted the T-system in November '
'2019. The attackers left the ransom note in HTML on the '
"company's computers and several files were added the .RYK "
'extension that is specific to Ryuk. The note had a contact '
'email address and instructions for paying the ransom.',
'motivation': 'Financial Gain',
'ransomware': {'ransomware_strain': 'Ryuk'},
'threat_actor': 'Ryuk Ransomware Group',
'title': 'Ryuk Ransomware Attack on T-System',
'type': 'Ransomware'}