CIMB said its online banking portal, CIMBClicks, remains secure and all customers' transactions continue to be protected.
"The bank would like to inform that it had, over the weekend, introduced a few additional measures to enhance the security of its CIMBClicks transactions.
"Apart from ensuring that the system is now able to accommodate passwords longer than eight characters and up to 20 characters, we have also added the reCaptcha security measure on CIMBClicks to ensure the user is not a bot," it said in a statement on Monday (Dec 17).
Over the weekend, purported issues with CIMB's online banking portal went viral after social media users claimed that funds from their online banking accounts had been transferred out to online payment site PayPal.
Users had also alleged that their passwords were opened for hacking.
Popular online forum Lowyat.net had also reported that serious security flaws in CLIMBClicks might have led to its accounts being hacked.