Horizon Alert
Summary of the vulnerability and why it matters
This issue affects applications using the `libcurl` library when configured with macOS's native TLS. It could trick these applications into using an unintended client certificate during secure connections, potentially exposing sensitive information or allowing unauthorized access. Pay attention because this could impact various applications that rely on `libcurl` for secure network communications.
- Sensitive certificate details can be exposed.
- Can lead to incorrect client authentication.
- Affects applications using `libcurl` on macOS.
Attack Path
How an attacker could exploit the issue
An attacker could trick an application using libcurl on macOS into using a malicious client certificate instead of the intended one. This occurs when the application's working directory is writable by others, allowing the attacker to create a file with the same name as the certificate the application expects to use by name, causing libcurl to use the file-based certificate.
- Requires local write access.
- Targets libcurl on macOS.
- Vulnerable if app runs in writable directory.
Live Threat
Current exploitation, exposure, and threat context
Attackers may find this CVE less appealing due to the requirement for a local attacker to manipulate the working directory. However, libcurl is a widely used library, potentially exposing many applications. The vulnerability could allow an attacker to trick an application into using a client certificate they control, potentially enabling unauthorized access or impersonation.
- Local prerequisite exists.
- No known exploit in the wild.
- Published over two years ago.
Priority actions
Operational Fix
Recommended remediation, mitigation, and detection steps
Prioritize identifying and isolating affected systems by analyzing logs for suspicious client certificate requests, especially from `/tmp` or other world-writable directories. Given the potential for attackers to trick applications into using malicious client certificates, it is crucial to block any network traffic exhibiting unusual certificate handshake behavior.
- Update libcurl to version 7.78.0 or later.
- Implement strict file permission checks on working directories.
- Monitor for anomalous TLS handshake certificate usage.
