A large phishing campaign has spoofed US-CERT and hindered the organisation's ability to handle email.
The Computer Emergency Response Team, which operates in the US Department of Homeland Security, issued a warning to internet users after the phishing email campaign emerged yesterday.
Attackers had spoofed US-CERT email addresses to target "a large number of private sector organisations as well as federal, state, and local governments".
An operator at US-CERT said it had difficulty receiving emails due to the phishing campaign.
The phishing emails have an attached .zip file that contains a malicious executable called "US-CERT Operation Center Reports" .eml.exe".
The emails were entitled "Phishing incident report" and included a phone number. The address firstname.lastname@example.org was the primary spoofed address but US-CERT notes other invalid email addresses were also used.
It advised that users do not open the email or attachments.
The attack follows a concerted phishing campaign allegedly from China that sent files infected with Microsoft and Adobe vulnerabilities to US organisations.
Once executed, infected machines would display public information about US unmanned aerial support vehicles, according to Alienvault analyst Jamie Blasco.