Security professionals slam Yahoo for being careless with user information after the company disclosed it was the victim of a malicious intrusion in which data associated with more than one billion user accounts was compromised. The disclosure comes less than three months after Yahoo reported another intrusion in September involving 500 million accounts. The breach has already raised more questions about Verizon Communication Inc.s pending $4.8 billion acquisition of the company. Some legal experts believed Verizon would try to negotiate that price down, citing a material adverse change clause in its pending agreement with Yahoo.”]