AWS Sign-in IAM User Login Vulnerability Affecting AWS Services

CVE-2025-0693

What is CVE-2025-0693?

CVE-2025-0693 identifies a vulnerability in the login process of AWS Identity and Access Management (IAM) for user accounts. AWS IAM is fundamental for managing access to AWS resources, allowing organizations to define who has access to specific services and what actions they can perform. This vulnerability could enable attackers to leverage brute force enumeration techniques, making it easier to discover valid IAM usernames within an organization's AWS environment. The implications of this flaw can be significant, as successfully identifying valid usernames is a critical step in planning further attacks, such as credential stuffing or phishing campaigns.

Technical Details

The vulnerability arises from variable response times during the AWS Sign-in IAM user login flow. This inconsistency can be exploited by adversaries to determine valid usernames based on the difference in response durations for valid versus invalid login attempts. By methodically attempting to log in with different usernames, attackers can use this information to narrow down valid user accounts in an arbitrary AWS account.

Potential Impact of CVE-2025-0693

1. Increased Risk of Account Compromise: The ability to enumerate valid IAM usernames significantly raises the risk of account compromise. Once usernames are identified, attackers can use various methods to attempt to gain unauthorized access, including credential stuffing or social engineering tactics.

2. Potential for Data Breaches: Should attackers gain access to valid IAM accounts, they may exploit this access to retrieve sensitive data, leading to potential data breaches that could affect customer trust, regulatory compliance, and overall organizational integrity.

3. Escalation of Attack Surface: By identifying valid IAM usernames, attackers can further target specific users with tailored phishing attacks, thereby expanding the attack surface and creating opportunities for more sophisticated, multi-faceted exploits against the organization's AWS infrastructure.

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