Mozilla has increased the bug bounty it pays security researchers sixfold to $3,000.

The move is designed to enlist more interest and support from flaw finders in the task of locating flaws in the code of Firefox and other software applications from Mozilla. Previously payments for eligible flaws in Firefox and Thunderbird earned just $500, under a bug bounty program first launched six years ago.

Eligible flaws need to be both critical and remotely exploitable. Payments are restricted to original security discoveries and exclude flaws in third-party plug-ins or browser extensions, however serious they might be. In addition, the scheme has been extended to cover vulnerabilities in Mozilla Mobile as well as Firefox and Thunderbird.

"For new bugs reported starting July 1st, 2010 UTC we are changing the bounty payment to $3,000 US per eligible security bug," explained Lucas Adamski, director of security engineering at Mozilla, in a blog post. "A lot has changed in the 6 years since the Mozilla program was announced, and we believe that one of the best way to keep our users safe is to make it economically sustainable for security researchers to do the right thing when disclosing information."

Mozilla's FAQ on its bug bounty program can be found here.

Google has also established a bug bounty program, offering $500 for run-of-the-mill flaws and a leet-friendly $1,337 for critical or particularly interesting flaws in Chromium, the open source code behind its Chrome web browser.

TippingPoint's Zero Day Initiative and VeriSign's iDefense have bought vulnerabilities from researchers for some years. Payments vary but tend to top out at around $10,000. The firms use the information to add signatures to its line of intrusion prevention appliances, in the case of TippingPoint, or security services informed by early warning of upcoming security problems, in the case of VeriSign.

While marketplaces for security research potentially offer higher returns there's still scope for programs from vendors that compensate security researchers for the time and effort needed for the tricky and skilled business of identifying and reporting software vulnerabilities. ®