Horizon Alert
Summary of the vulnerability and why it matters
Apache CXF's Security Token Service has a vulnerability where it incorrectly validates security tokens by relying on a weak hashing mechanism. This could allow an attacker to bypass authentication and impersonate other users to gain access to services or resources.
- Authentication bypass using token hash collisions.
- Critical for services handling user authentication and token validation.
- Assess and confirm exposure to this authentication bypass risk.
Attack Path
How an attacker could exploit the issue
An attacker could exploit this vulnerability by crafting a security token that mimics the hash of a previously validated token. This allows the attacker to bypass authentication checks, such as password validation and signature verification, and impersonate another user. Once authenticated, the attacker can obtain STS-signed tokens for the impersonated identity, potentially gaining unauthorized access to resources or performing actions on behalf of that user.
- No prior authentication required.
- Crafted token causes hash collision.
- Impersonate users and gain access.
Live Threat
Current exploitation, exposure, and threat context
When supported by the advisory, an attacker could craft a token that collides with a cached entry, bypassing security checks and potentially authenticating as another user. This could lead to unauthorized access and the ability to obtain STS-signed tokens for an impersonated identity.
- System tokens and validated security tokens.
- Token hash collision leading to cache bypass.
- Unauthorized authentication and token acquisition.
Operational Fix
Recommended remediation, mitigation, and detection steps
Teams responsible for web services, APIs, and identity management, including application owners, platform teams, and security operations, should address this vulnerability. The immediate priority is to identify all instances of Apache CXF's Security Token Service, determine their reachability and business criticality, and assign an owner for remediation planning.
- Identify and assign CXF STS ownership.
- Verify STS instances and their exposure.
- Plan remediation based on risk assessment.
