CVE-2020-24356: 
Cloudflared vulnerability analysis and mitigation

CVE-2020-24356 affects cloudflared versions prior to 2020.8.1, containing a local privilege escalation vulnerability on Windows systems. When run on a Windows system, cloudflared searches for configuration files which could be abused by a malicious entity to execute commands as a privileged user (NVD, GitHub Advisory).

The vulnerability stems from a misconfiguration in how cloudflared reads its configuration files on Windows systems. The application reads from C:\etc directory, which lacks default security controls in Windows. An unprivileged user can write a malformed config.yaml file that controls the log file location, which can be set to a location that Windows executes during user login. The vulnerability has a CVSS v3.1 base score of 7.8 (HIGH) according to NVD, with vector string CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H (NVD).

Successful exploitation of this vulnerability allows an unprivileged user to escalate privileges and execute system-level commands on affected Windows systems. This can lead to complete system compromise when an administrator has configured cloudflared to read configuration files from specific directories (GitHub Advisory).

The vulnerability requires local access to the system and can be exploited when an administrator has started cloudflared and configured it to read configuration files from certain directories. The attack involves creating a malformed config.yaml file in an unsecured directory (GitHub Advisory).

The vulnerability was fixed in cloudflared version 2020.8.1. Users are advised to upgrade to this version or later to protect against this security issue (NVD, GitHub Advisory).