Protecting accounts from credential stuffing with password breach alerting
Abstract
Protecting accounts from credential stuffing attacks remains
burdensome due to an asymmetry of knowledge: attackers
have wide-scale access to billions of stolen usernames and
passwords, while users and identity providers remain in the
dark as to which accounts require remediation. In this paper,
we propose a privacy-preserving protocol whereby a client can
query a centralized breach repository to determine whether
a specific username and password combination is publicly
exposed, but without revealing the information queried. Here,
a client can be an end user, a password manager, or an identity
provider. To demonstrate the feasibility of our protocol, we
implement a cloud service that mediates access to over 4
billion credentials found in breaches and a Chrome extension
serving as an initial client. Based on anonymous telemetry
from nearly 670,000 users and 21 million logins, we find that
1.5% of logins on the web involve breached credentials. By
alerting users to this breach status, 26% of our warnings result
in users migrating to a new password, at least as strong as
the original. Our study illustrates how secure, democratized
access to password breach alerting can help mitigate one
dimension of account hijacking.
burdensome due to an asymmetry of knowledge: attackers
have wide-scale access to billions of stolen usernames and
passwords, while users and identity providers remain in the
dark as to which accounts require remediation. In this paper,
we propose a privacy-preserving protocol whereby a client can
query a centralized breach repository to determine whether
a specific username and password combination is publicly
exposed, but without revealing the information queried. Here,
a client can be an end user, a password manager, or an identity
provider. To demonstrate the feasibility of our protocol, we
implement a cloud service that mediates access to over 4
billion credentials found in breaches and a Chrome extension
serving as an initial client. Based on anonymous telemetry
from nearly 670,000 users and 21 million logins, we find that
1.5% of logins on the web involve breached credentials. By
alerting users to this breach status, 26% of our warnings result
in users migrating to a new password, at least as strong as
the original. Our study illustrates how secure, democratized
access to password breach alerting can help mitigate one
dimension of account hijacking.
Research Areas
