NSA Purges Hundreds of Millions of Call and Text Records

WASHINGTON — The National Security Agency has purged hundreds of millions of records logging phone calls and texts that it had gathered from U.S. telecommunications companies since 2015, the agency has disclosed. It had realized that its database was contaminated with some files the agency had no authority to receive.

The agency began destroying the records May 23, it said in a statement. Officials had discovered “technical irregularities” this year in its collection from phone companies of call record details, or metadata showing who called or texted whom and when, but not what they said.

The agency had collected the data from a system it created under the USA Freedom Act. Congress enacted that law in 2015 to end and replace a once-secret program that had systematically collected Americans’ domestic calling records in bulk. The NSA uses the data to analyze social links between people in a hunt for hidden associates of known terrorism suspects.

The program traces back to a component of the once-secret Stellarwind surveillance program the Bush administration put in place after the Sept. 11, 2001, attacks. The data collection eventually came to be justified under disputed interpretation of a law known as Section 215 of the Patriot Act and was exposed in 2013 in the leaks by Edward J. Snowden, the former intelligence contractor.

The disclosure caused an uproar, and Congress eventually enacted the Freedom Act to end and replace the program. Under the new system, the bulk data about Americans’ phone calls and texts has instead remained in the hands of telecoms, and the NSA may collect only specific sets of records from it: the phone logs of a surveillance target and of everyone that person has contacted. A judge must also agree that there is reason to suspect the target has links to terrorism.

Under the Freedom Act, the agency took in 151 million call-detail records in 2016 and 534 million such records in 2017, according to government reports.

David Kris, a founder of the Culper Partners consulting firm who led the Justice Department’s National Security Division in the first term of the Obama administration, called the disclosure “a failure” of the implementation of the USA Freedom Act, which is set to expire next year if Congress does not enact new legislation extending it.

“The fact that they need to purge all of the data they received pursuant to queries over the last three years is evidence of that failure,” said Kris, adding that the errors illustrated how new problems can sometimes crop up when the government makes systems more complex in an effort to better balance security and privacy.

The NSA did not explain what technical irregularities caused the problem. But an agency spokesman, Chris Augustine, said the problem did not result in any collection of location records from cellphone towers. Under the USA Freedom Act, the agency is not permitted to gather that type of record using its system.

Glenn S. Gerstell, the NSA’s general counsel, said that because of several complex technical glitches, one or more telecom providers — he declined to say which — had responded to court orders for targets’ records by sending logs to the agency that included both accurate data and also some numbers of people the targets had not been in contact with.

As a result, when the agency then fed those phone numbers back to the telecoms to get the communications logs of all the people who had been in contact with its targets, the agency also gathered some data of people unconnected to the targets. The NSA had no authority to collect their information.

“If the first information was incorrect, even though on its face it looked like any other number, then when we fed that back out, by definition we’d get records back on the second hop that we did not have authority to collect,” he said.

In a statement, Sen. Ron Wyden, D-Ore., who is on the Senate Intelligence Committee and is often a critic of surveillance programs from a privacy rights perspective, blamed telecoms — not the government — for the problem.

“Telecom companies hold vast amounts of private data on Americans,” Wyden said. “This incident shows these companies acted with unacceptable carelessness, and failed to comply with the law when they shared customers’ sensitive data with the government.”

The agency worked with telecommunications companies to figure out the sources of the problem, Gerstell added, and was satisfied that it was fixed going forward. But because it was deemed infeasible to try to identify and selectively delete the contaminated records in the database, he said, they instead decided to purge all of them.

The NSA said in its statement that it had separately “reviewed and revalidated its intelligence reporting to ensure that the reports were based on properly received” data. Gerstell said that vetting process had been done manually.