By Sean Lyngaas, Gabe Cohen, CNN(CNN) — An unidentified hacker stole sensitive data from Customs and Border Protection and Federal Emergency Management Agency employees in a “widespread” breach this summer that lasted several weeks, according to an internal FEMA assessment reviewed by CNN. The document, which was presented to FEMA staff this week in an update on the breach, reveals just how easily the attacker bypassed the agency’s digital defenses. In mid-July, as the intruder navigated FEMA’s systems and attempted to extract sensitive information, DHS launched its initial efforts to contain and halt the breach. Yet, according to the assessment, nearly two months later — by September 5 — DHS and FEMA were still trying to remediate the incident. It was not immediately clear if the FEMA breach is related to that activity.