Ukrposhta

It was a DDoS (distributed denial-of-service) attack that caused such disruptions.

Ukrposhta along with internet providers tried to restore both the online store and systems.

However, Moscow has been consistently denying accusations it has launched cyberattacks on Ukraine.

Source: https://www.reuters.com/world/europe/ukraines-postal-service-hit-by-cyberattack-after-sales-warship-stamp-go-online-2022-04-22/

"id": "UKR04123422",
"linkid": "ukrposhta",
"type": "Cyber Attack",
"date": "04/2022",
"severity": "100",
"impact": "9",
"explanation": "Attack that could bring to a war"