CVE-2020-4071: Information Exposure Through Timing Discrepancy

A potential timing attack exists on websites where the basic authentication is used or configured, i.e. BASIC_AUTH_LOGIN and BASIC_AUTH_PASSWORD is set. Currently, the string comparison between configured credentials and the ones provided by users is performed through a character-by-character string comparison. This enables a possibility that attacker may time the time it takes the server to validate different usernames and password, and use this knowledge to work out the valid credentials. This attack is understood not to be realistic over the Internet. However, it may be achieved from within local networks where the website is hosted, e.g. from inside a data centre where a website’s server is located.