The Department of Social Protection which looks after all welfare payments was targeted by hackers before the HSE system but its firewall held up, the Irish Mirror can reveal.
And it emerged this morning that the Department of Health was also hit by the Eastern European gang.
The Irish Mirror has now learned the Department of Social Protection came under "sustained and fierce attack" but the highly-organised criminal group were unable to breach the security.
Social Protection deals with Ireland's entire social welfare system and a hack would have wreaked havoc on all payments including dole.
A source told the Mirror: "They came under sustained and fierce attack in recent months but luckily firewalls held, if they hadn't it would have been carnage.
"They only got into the HSE because it's just one central platform with thousands of systems with weak security, it's wide open to organised hackers."
The Irish Mirror understands the hackers have secretly been inside the HSE systems for several weeks.
The Department of Health is the latest victim of the cyber attack which is similar to the attack on the HSE and it has shut down its systems.
The Department of Social Protection have been contacted for comment.
Meanwhile the HSE are currently working to restore their systems after their firewalls were passed by the Eastern European gang.
HSE Chief Paul Reid confirmed on Saturday that a ransom demand had been made but wouldn't comment on how much the gang were requesting.
