Hundreds of secret documents he sent NATO in Portugal were spotted for sale on the dark web after cyber attack against the General Staff of the country’s armed forces and army intelligence, according to the newspaper Diario de Noticias.

“This is a cyber attack that went on for a long time and went unnoticed, by bots programmed to detect this kind of document,” said one of the anonymous sources cited by the newspaper.

According to Diario de Noticias, the incident was noticed by American intelligence agencies, who informed the Portuguese authorities about it in August through the American embassy in Lisbon.

An investigation by the Portuguese cybersecurity service named the general headquarters of the armed forces, the army intelligence service and an agency of the Ministry of Defense as the targets of the attack.

“The government is able to ensure the daily work of the Ministry of Defense and the armed forces to maintain the authority of Portugal as a founding member of the Atlantic Union,” Prime Minister Antonio Costa said.

“Every time a violation is suspected (…), the situation is carefully analyzed” and measures are taken “to strengthen cyber security,” the Portuguese government added, without either confirming or denying the newspaper’s report.

According to Diario de Noticias, the documents in question were exchanged between various Portuguese agencies through insecure communication channels.

^{Sources: APE-MPE, AFP.}