Shares in TalkTalk climbed more than 12 per cent, following the company's first half fiscal report to the City this morning.
The budget telco's boss Dido Harding was bullish about TalkTalk's response to the attack on its systems last month.
She claimed during a conference call with journalists and analysts that some customers had initially attempted to kill their contracts immediately after TalkTalk revealed it had suffered a security breach, only to apparently change their minds following the "blip" in demand to abandon the service.
Harding added that there were "very early indications that customers think that we're doing the right thing".
TalkTalk has repeatedly claimed that it had been completely transparent with customers about the attack on its website. On Wednesday morning, the firm said that the "majority of customers support our approach".
Half of the £35m costs that TalkTalk expects to swallow following the breach, which the company has said hit nearly 157,000 subscribers (four per cent of its customer base), is one-off in nature, according to TalkTalk's chief beancounter, Iain Torrens.
Harding explained that the bill covers incident response, incremental call volumes, internal IT costs and external IT consulting costs. TalkTalk called in BAE Systems and other security experts, following the attack.
"Forgone revenue of having sales sites down for three weeks is something to work through," she added.
The telco's chief reiterated that TalkTalk needed to do more to win back the confidence of its customers.
"The cyber attack, while not wishing to diminish it, has been smaller than we thought," she said. Harding added that the ISP was "very confident in the medium term future of TalkTalk".
"Yesterday's security might have been good enough but it's not going to be good enough tomorrow," she said. "I expect we will take security considerably more seriously than ever."
Shares in the company are currently trading up 12.24 per cent at 243.4p on the London Stock Exchange. ®