People create fake versions of big companies’ websites all the time, usually for phishing purposes. But the companies do not usually link to them by mistake.

Equifax, however, did just that after Nick Sweeting, a software engineer, created an imitation of equifaxsecurity2017.com, Equifax’s page about the security breach that may have exposed 143 million Americans’ personal information. Several posts from the company’s Twitter account directed consumers to Mr. Sweeting’s version, securityequifax2017.com. They were deleted after the mistake was publicized.

By Wednesday evening, the Chrome, Firefox and Safari browsers had blacklisted Mr. Sweeting’s site, and he took it down. By that time, he said, it had received about 200,000 hits.