Clearly, there have been serious attempts at infiltration. And did any of the infiltrators slip by and into the CIA? Given the fact that our government is committed to politically correct willful ignorance about the nature of Islam and jihad, and thus is unlikely to know how to screen applicants properly on these matters, that is not just a possibility; it's a certainty.
"CIA finds 1-in-5 job applicants hail from Hamas, Hezbollah, al Qaeda," by Cheryl K. Chumley for The Washington Times, September 2 (thanks to Kenneth):
An estimated one-fifth of all applicants for Central Intelligence Agency positions had significant ties to the terror groups, Hamas, Hezbollah and al Qaeda, a newly released document from the Edward Snowden collection revealed on Monday.
The document — released by Mr. Snowden as part of his National Security Agency intelligence dump — said that the terrorist groups worked hard to infiltrate America’s top security agencies. CIA officials uncovered thousands of applicants, roughly 1-in-5, with “significant terrorist and/or hostile intelligence connections,” the document states, Ynet News reported.
The specifics of those ties were not revealed. But the groups most often cited as attempting to infiltrate the U.S. intelligence network were al Qaeda, Hamas and Hezbollah.
The NSA, in response, launched investigations into 4,000 instances of suspected abnormal staff activity, Ynet News said. Those investigations included the tracking of employee keystrokes on agency computers and the recording of document downloads.
“Over the last several years, a small subset of CIA’s total job applicants were flagged due to various problems or issues,” one unnamed agency official said, Ynet News reported. “During this period, one in five of that small subset was found to have significant connections to hostile intelligence services and-or terrorist groups.”