The agency said in a Thursday advisory that it has received reports of new junk mail campaigns and phishing sites related to the inauguration.
Spammers and malware writers typically coincide their attacks with major current events, US-CERT said.
Users are reminded to run an updated anti-virus package and to not follow links they do not trust or open unknown emails.
The new wave comes despite a report this week from McAfee that spam levels have fallen 40 percent off their highs in November, prior to the shutdown of McColo, a rogue internet service provider that was being used by cybercriminals to host their attacks.