CVE-2023-36672

Published: 9 August 2023

An issue was discovered in the Clario VPN client through 5.9.1.1662 for macOS. The VPN client insecurely configures the operating system such that traffic to the local network is sent in plaintext outside the VPN tunnel even if the local network is using a non-RFC1918 IP subnet. This allows an adversary to trick the victim into sending arbitrary IP traffic in plaintext outside the VPN tunnel. NOTE: the tunnelcrack.mathyvanhoef.com website uses this CVE ID to refer more generally to "LocalNet attack resulting in leakage of traffic in plaintext" rather than to only Clario.

Notes

other VPN software may also be affected. See whitepaper for the
complete list.

as of 2024-02-05, there doesn't appear to be an upstream fix
available for network-manager-openvpn, openvpn packages.
as of 2024-02-29, there doesn't appear to be an upstream fix
available for network-manager-pptp, pptp-linux.
wireguard itself is not vulnerable, however the wg-quick
tool includes local network access. See the wg-quick manpage
and documentation on methods to disable this.

as of 2024-04-15, this CVE appears to be specific to the
Clario VPN client, marking all Ubuntu packages as
not-affected

Status

Severity score breakdown

References

• https://tunnelcrack.mathyvanhoef.com/details.html
• https://papers.mathyvanhoef.com/usenix2023-tunnelcrack.pdf
• https://openvpn.net/security-advisory/statement-regarding-tunnelcrack-vulnerabilities/
• https://www.softether.org/9-about/News/905-TunnelCrack
• https://www.cve.org/CVERecord?id=CVE-2023-36672
• NVD
• Launchpad
• Debian