CVE-2023-36673

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 servers 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 servers 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.

Weakness

The product transmits sensitive or security-critical data in cleartext in a communication channel that can be sniffed by unauthorized actors.

Affected Software

Potential Mitigations

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/102.html
• https://cwe.mitre.org/data/definitions/117.html
• https://cwe.mitre.org/data/definitions/383.html
• https://cwe.mitre.org/data/definitions/477.html
• https://cwe.mitre.org/data/definitions/65.html

References

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