ANZ Bank has removed access to its electronic statements and will fall back to paper after SC Magazine broke the story that a bug in URLs placed customer data at risk.
It will take weeks to fix the issue, ANZ said.
The flaw exists because online bank statements remain stored permanently in browser histories.
Statements were not tied to specific browser sessions and did not expire, meaning identity thieves could plunder troves of statements stored in browser histories of public terminals.
SC informed the bank of the vulnerability more than a week in advance of the publication of this story to allow it time to act on the flaw.
Customers could mitigate expose to the flaw by wiping browser histories when using shared computer terminals.
ANZ said it will work with outsourcer Salmat to repair the bug in its eStatements.
“This means that customers that have currently elected to receive electronic statements will now receive a hard copy statement until the issue is resolved,” a spokesman said.