"The malware may have sat unnoticed on at least one victim computer for years, although Kaspersky Lab researchers still have not confirmed that suspicion." So

"The malware may have sat unnoticed on at least one victim computer for years, although Kaspersky Lab researchers still have not confirmed that suspicion." So it might not have? And they're not sure? And "at least one" means it might only be one. All this makes me highly suspicious of the article.