Horizon Alert
Summary of the vulnerability and why it matters
A vulnerability in the hackney_ssl component of the benoitc hackney library could allow an attacker to impersonate a server if they possess a valid certificate for the target hostname. This occurs due to improper handling of certificate validation, where a publicly trusted root can be accepted even when the connection is intended to be pinned to a private certificate authority.
- Server impersonation possible with valid hostname certificate.
- Affects applications using hackney for secure connections.
- Confirm relevance and assess exposure of your services.
Attack Path
How an attacker could exploit the issue
An attacker positioned between the vulnerable application and the target server can trick the application into trusting a malicious server. This is achieved by presenting a certificate that appears to be valid because it chains to a publicly trusted root, even though the application was configured to only trust a private certificate authority. The attacker must possess a valid certificate for the target hostname to succeed.
- Requires an on-path network position.
- Triggered by connecting to a malicious server.
- Risk of server impersonation.
Live Threat
Current exploitation, exposure, and threat context
An attacker on the same network could impersonate a server by presenting a certificate chain that appears valid to the affected library, potentially allowing them to intercept or manipulate traffic when supported by the advisory.
- Server impersonation could occur.
- Attackers may intercept traffic.
- Sensitive data exposure is possible.
Operational Fix
Recommended remediation, mitigation, and detection steps
The Improper Certificate Validation vulnerability in hackney_ssl affects applications using the benoitc hackney library for outbound connections. Responsibility likely lies with the application development teams who integrate this library and the platform teams that manage the underlying runtime environments. The first practical step is to identify all applications utilizing hackney, determine their exposure to untrusted networks, and confirm the accountable owners for each.
- Application owners should own the issue.
- Verify hackney usage and network exposure.
- Plan remediation based on risk assessment.
