Edward Snowden took advantage of the "perfect storm" of security lapses at the National Security Agency, says the director of national intelligence, allowing the former contractor to scoop up highly classified documents, some of which could expose the identities of undercover intelligence operatives.During testimony Tuesday before the Senate Armed Services Committee, James Clapper also said that while the NSA has since installed security upgrades, some locations continue to be without the software and warning systems that could detect similar security breaches, The New York Times reports "There are no mousetraps that we could say that we can guarantee that we'll never have another Edward Snowden," Clapper said.Clapper also confirmed a Times report that Snowden used a web crawler, a commonly available piece of software, to gather a large number of documents, though he did not explain why the agency was not able to detect it.Since the unprecedented leaks last June, the agency has adopted new rules to significantly restrict the sharing and downloading of top-secret information, including a "two-man rule" that requires two computer systems administrators to work simultaneously whenever highly classified material is being accessed.Clapper said that all 16 of the country's intelligence agencies will ultimately adopt a complex system to tag every piece of information in their databases and link it to anyone who accesses it for real-time security monitoring.Snowden remains in exile in Russia. To date, the information Snowden has released to the media has not revealed the names of intelligence agents or operatives, and it is not apparent how much of that information he currently has in his possession.At the hearing, Clapper and Lt. Gen. Michael Flynn, director of the Defense Intelligence Agency, also revealed that American analysts believe Iran will be ready to test an intercontinental ballistic missile by next year, the Times reports.