The "Heartbleed" flaw in Internet security is as critical as thename implies and wider spread than first believed.Warnings about the danger exposed early this week reached widening circles onThursday, with everyone from website operators and bank officials to Internetsurfers and workers who tele-commute being told their data could be in danger."Heartbleed is a catastrophic bug in OpenSSL," well-known computer security specialist Bruce Schneier said in a post at his schneier.com website.OpenSSL is a commonly used software platform for encrypted transactions at"https" websites that Internet users have been taught to trust.The Heartbleed flaw lets hackers snatch packets of data from working memory incomputers, creating the potential for them to steal passwords, encryption keys, orother valuable information."This is going to be a pretty devastating bug," Trustwave security research managerJohn Miller told AFP."Even after the majority of it is fixed on the Internet, there will be internal servicesvulnerable."- Threat widens -The Heartbleed flaw can be found in virtual private network (VPN) softwarecommonly used by workers on the go to securely link with company computernetworks.Computer networking titans Cisco and Juniper put out advisories on Thursday thatsome of their data-handling gear is susceptible to the bug."An exploit could allow the attacker to disclose a limited portion of memory from aconnected client or server," California-based Cisco said in an advisory note."The disclosed portions of memory could contain sensitive information."Canada's tax agency shuttered its website Wednesday after warning that encryptedtaxpayer data could be vulnerable.OpenSSL is commonly used to protect passwords, credit card numbers and other data sent via the Internet.Web masters have been scrambling to update to safe versions of OpenSSL. Thevulnerability has existed for about two years, since the version of OpenSSL at issuewas released.The Tor Project devoted to letting people use the Internet anonymously advisedthose in need of privacy to stay offline until the Heartbleed threat is ameliorated.- Crown jewels at risk Information considered at risk includes source codes, passwords, and "keys" thatcould be used to impersonate websites or unlock encrypted data."These are the crown jewels, the encryption keys themselves," said a heartbleed.comwebsite devoted to details of the vulnerability."Leaked secret keys allows the attacker to decrypt any past and future traffic to theprotected services and to impersonate the service at will."The flaw in OpenSSL allows a hacker to read the memory of a machine working thesoftware, but no more than 64 kilobytes of data at a time, according to securityspecialists.However, hackers could repeatedly grab packets of memory to ramp up the odds ofstealing valuable data."We don't know how actively Heartbleed was exploited before publication of thevulnerability," Trustwave's Miller told AFP."Since Monday, when they published, it has been used a lot. People have beenexecuting the attack all over the Internet." OpenSSL is used by more than half of websites, but not all versions have thevulnerability, according to heartbleed.com.The group behind open-source OpenSSL is urging users to upgrade to an improvedversion of the software and gave credit for finding the bug to Neel Mehta of GoogleSecurity.Major websites and services were given advanced word of the Heartbleed flaw toallow time for patches to be put in place before the flaw was made public.Miller and other security specialists said Heartbleed appeared to be the result of amistake in writing the OpenSSL code.Software patches and updates were being rushed out, but it was expected to taketime for websites, businesses, router makers and others on the growing list of thoseat risk to replace software keys used to prevent impersonation or safeguardencrypted data.Websites need to change credentials used to verify authenticity in order to preventhackers who may have looted the data from impersonating legitimate online venueand tricking visitors to enter valuable personal information.Internet users were advised to change passwords to online accounts or services, butonly after checking to make sure the Heartbleed flaw has been fixed and newcertificates of online identity installed.While Heartbleed has shaken trust in the Internet, it may well wind up providinginsight into which websites or services deserve to be trusted."I don't think its a matter of losing faith," Miller said."It is really going to be an individual measure of how organizations respond; andwe can start to judge their security postures.