The U.S. National Security Agency, which has a cybersecurity mission in addition to surveillance, has disputed a report that it knew about the Heartbleed security vulnerability for at least two years before other researchers disclosed the flaw this month.The NSA used Heartbleed to gather intelligence, according to a report from Bloomberg, quoting two anonymous sources. Heartbleed is a flaw in OpenSSL that could allow attackers to monitor all information passed between a user and a Web service.But an NSA spokeswoman called the report incorrect. "NSA was not aware of the recently identified vulnerability in OpenSSL, the so-called Heartbleed vulnerability, until it was made public in a private-sector cybersecurity report," she said by email. "Reports that say otherwise are wrong."At the same time that the NSA was accused of using Heartbleed to conduct surveillance, another agency was trumpeting its efforts to share information about the bug.After information about the bug was published, the U.S. Department of Homeland Security's U.S.-Computer Emergency Readiness Team (US-CERT) "immediately issued\u00a0an alert\u00a0 to share actionable information with the public and suggested mitigation steps," said Larry Zelvin, director of the DHS National Cybersecurity and Communications Integration Center.DHS also reached out to some businesses to help determine their vulnerability, Zelvin wrote in a blog post."While there have not been any reported attacks or malicious incidents involving this particular vulnerability confirmed at this time, it is\u00a0still possible that malicious actors in cyberspace could exploit unpatched systems," he wrote. "That is why everyone has a role to play to ensuring our nation's cybersecurity."Alan Paller, director of research at cybersecurity training organization the SANS Institute, said the NSA's surveillance mission has a higher priority than its cyberdefense mission."The offensive mission is the better funded and more visible part of NSA," he said by email. "In a competition between disclosure and nondisclosure, the offense will generally win."Grant Gross covers technology and telecom policy in the U.S. government for The IDG News Service. Follow Grant on Twitter at GrantGross. Grant's email address is email@example.com.