A Yahoo Inc. advertiser has accused the Internet search engine of fraud, saying its ads have been appearing in spyware and “typosquatter” Web sites that take advantage of misspelled trademarks.

Crafts By Veronica, which makes fabric-covered photo albums, filed a lawsuit accusing Yahoo of breaching a contract by charging advertisers for pay-per-click ads shown improperly in “pernicious spyware programs” and on low-quality Web sites.