Adobe Systems Inc said it is taking longer than expected to warn customers about a massive data breach that compromised data on tens of millions of people, leaving some in the dark 10 weeks after the attack was discovered. That puts those who have yet to be alerted at increased risk of cyber-scams and identity theft, because part of the massive trove of data stolen from Adobe is circulating on the Internet. This is a pretty massive screw-up, said Chester Wisniewski, a senior security advisor at anti-virus software maker Sophos. Its not a secret. Adobe identified the attack on September 17 and began notifying customers immediately after it disclosed the breach on October 3, according to company spokeswoman Heather Edell.