The virus was stopped with virus protection software and posed no threat to ISS systems or operations, said NASA spokesperson Kelly Humphries.
Citing NASA security policies, Humphries said he could not disclose further details about how the virus was brought to the ISS.
Like billionaires, computer viruses occasionally make the trip into space. "It's not the first virus we've seen on the station," said Humphries. "It's not a common occurrence by any means."
None of the previous computer viruses found on computers aboard the ISS have had any operational impact, said Humphries.
News that a virus had been identified on the ISS was first reported on Monday by online news site SpaceRef.com, which identified the virus as W32.Gammima.AG worm, malware designed to steal logon information from online gamers.
It's unlikely that ISS astronauts are playing World of Warcraft in their spare time, however, because the ISS does not have a direct Internet connection.
NASA is currently reviewing the incident and may make procedural recommendations based on its findings.
The SpaceRef report suggested that a flash card or USB drive brought on board by an astronaut may have been the source of the laptop infection.