The federal police have opened an investigation into suspected espionage following an attack by hackers of the computer system of two government departments.
A spokeswoman said the foreign ministry and State Secretariat for Economic Affairs (Seco) were the target of professional hackers at the end of last year.
A cyber crime expert said the case was unique since employees in particular departments of the federal administration were singled out for the attack.
However, the foreign ministry said there was no reason to believe any sensitive data was stolen, and Seco added that it was "practically unaffected" since the attack was immediately uncovered and dealt with.
Around 500 emails were sent to the two offices at the end of November and beginning of December.
The mails were correctly addressed using the first names of staff members and disguised as originating from another federal department.
The files attached to the mails contained "malware" (malicious software) which was not immediately recognised by the administration's anti-virus software.
Switzerland's cyber crime unit says such attacks could be supported by public institutions or organised bands. Often targeted are sensitive defence information or foreign policy data.
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