What is a significant disadvantage of SSO?

The significant disadvantage of Single Sign-On (SSO) relates to the potential for a single key to compromise all resources. SSO allows users to authenticate once and gain access to multiple applications or resources without needing to log in separately for each. While this greatly enhances user convenience and can improve productivity, it also introduces a security risk.

If an attacker gains access to a user's SSO credentials, they can potentially access all applications and data that the user has permission to use. This creates a single point of failure, meaning that the breach of those credentials can lead to widespread unauthorized access. In environments where sensitive data is managed across various applications, the implications of such a compromise can be severe, potentially leading to data breaches and loss of sensitive information.

The other choices, while they may indicate concerns related to password management and administrative workload, do not encapsulate the overarching security risk that SSO presents. The central issue with SSO is its reliance on a single set of credentials that, if compromised, can lead to extensive access across multiple critical resources.