The US Office of Personnel Management says that hackers have actually gained access to 5.6 million fingerprint records rather than the one million originally reported by the federal agency.
The OPM made the announcement in a Wednesday statement that was “part of the government’s ongoing work to notify individuals affected by the theft of background investigation records.”
“Of the 21.5 million individuals whose Social Security Numbers and other sensitive information were impacted by the breach, the subset of individuals whose fingerprints have been stolen has increased from a total of approximately 1.1 million to approximately 5.6 million,“ it read.
The hack against federal employees, which took place in December 2014, is already the biggest one against the government in the US history.
Those whose fingerprints have been hacked are particularly more vulnerable as there is no way to change them.
OPM, however, said “the ability to misuse fingerprint data is limited” yet warned that the “probability could change over time as technology evolves.”
“If, in the future, new means are developed to misuse the fingerprint data, the government will provide additional information to individuals whose fingerprints may have been stolen in this breach,” the OPM said.
Washington has for years accused the Chinese government and military of conducting computer-based attacks against the US, including efforts to steal information from federal agencies.
It claims that the Chinese military has made cyber warfare capabilities a priority over a decade ago and often blames people linked to it for hacking into US companies’ computers to steal secrets.
Beijing says Washington’s cyber attack accusations are hypocritical, since intelligence leaks have revealed that the US itself is most active perpetrator of cyber espionage against foreign countries, especially against China.
The OPM increased the figure as Chinese President Xi Jinping was on a state visit to the US.
"China is a strong defender of cybersecurity. China is also a victim of hacking attacks. The Chinese government will not, in any way, participate, encourage or support the theft of commercial secrets by anyone,” Xi said in Seattle on Tuesday.
The breach was discovered in April this year, followed by discovery of a second one in July, which raised the number for those affected to 21 million.
OPM said it is “committed to delivering high-quality identity protection services to impacted individuals.”