Vulnerability · Published Mar 23, 2023 · Assigned by GitHub_M
CVE-2023-28436Non-interactive Tailscale SSH sessions on FreeBSD may use the effective group ID of the tailscaled process
Medium 5.7
In plain English
A medium-severity privilege mismanagement in tailscale from tailscale. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 40% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
Tailscale is software for using Wireguard and multi-factor authentication (MFA). A vulnerability identified in the implementation of Tailscale SSH starting in version 1.34.0 and prior to prior to 1.38.2 in FreeBSD allows commands to be run with a higher privilege group ID than that specified in Tailscale SSH access rules. A difference in the behavior of the FreeBSD `setgroups` system call from POSIX meant that the Tailscale client running on a FreeBSD-based operating system did not appropriately restrict groups on the host when using Tailscale SSH. When accessing a FreeBSD host over Tailscale SSH, the egid of the tailscaled process was used instead of that of the user specified in Tailscale SSH access rules. Tailscale SSH commands may have been run with a higher privilege group ID than that specified in Tailscale SSH access rules if they met all of the following criteria: the destination node was a FreeBSD device with Tailscale SSH enabled; Tailscale SSH access rules permitted access for non-root users; and a non-interactive SSH session was used. Affected users should upgrade to version 1.38.2 to remediate the issue.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Go | tailscale.com | 1.38.2 | GHSA-vfgq-g5x8-g595 |
| Go | tailscale.com | 1.38.2 | GO-2023-1671 |
Affected products (as reported)
Weakness: CWE-269 · Vector: CVSS:3.1/AV:A/AC:L/PR:H/UI:R/S:C/C:H/I:N/A:N
References
- https://github.com/tailscale/tailscale/security/advisories/GHSA-vfgq-g5x8-g595 x_refsource_CONFIRM
- https://github.com/tailscale/tailscale/commit/d00c046b723dff6e3775d7d35f891403ac21a47d x_refsource_MISC
- https://github.com/tailscale/tailscale/releases/tag/v1.38.2 x_refsource_MISC
- https://tailscale.com/security-bulletins/#ts-2023-003 x_refsource_MISC