Wipro victim to sophisticated phishing attack?
"We detected a potentially abnormal activity in a few employee accounts on our network due to an advanced phishing campaign."
My interpretation is some local call-center operatives were supplementing their income by running phishing scams, possibly even from the same facility. It would explain how valid customer details would end up in the hands of the scammers. One such case being phone-calls apparently from a valid TalkTalk helpdesk. The call being verified with correct security details.
Biting the hand that feeds IT
