The Israeli computer security firm Trusteer Ltd. said Thursday that it has enhanced its Rapport anti-phishing service to better combat the latest fraud techniques.

The Tel Aviv company said that its software can detect phish sites that are savvy enough to trick the phishing blacklists built into modern Web browsers.

When a user with Trusteer's Rapport software connects to a potentially fake financial site, Trusteer compares the site to those of its clients to determine the site's legitimacy.

If Trusteer determines that the site is fake, the company said, it can immediately notify the financial institution not only of the bogus site but also of the specific account details the site stole in that instance.

The vendor said these sites can sidestep browser filters because they are more targeted and deliberately designed to combat the techniques used by browser developers. When Rapport catches a new phish site, it alerts browser firms so they can update their blacklists.

The enhanced Rapport "provides timely alerts that allow financial institutions and other online businesses to protect customer accounts against attacks that bypass anti-phishing filters as well as [against] operator error by the end-user," Mickey Boodaei, Trusteer's chief executive, said in a press release.

The discount brokerage firm Muriel Siebert & Co. Inc. has agreed to use the enhanced Rapport. Muriel Siebert, the New York firm's founder, president, chief executive, and chairwoman, said in the press release: "We believe that the new Trusteer anti-phishing service will create a valuable additional layer of protection for us and our account holders."