Ubuntu.comUB:CVE-2023-36673CVE-2023-36673
7.3 High
CVSS3
Attack Vector
ADJACENT
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
NONE
CVSS:3.1/AV:A/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N
0.001 Low
EPSS
Percentile
21.5%
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.
Notes
| Author | Note |
|---|---|
| mdeslaur | other VPN software may also be affected. See whitepaper for the complete list. |
| evancaville | 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. |
| mdeslaur | as of 2024-04-15, this CVE appears to be specific to the Avira Phantom VPN, marking all Ubuntu packages as not-affected |
| OS | Version | Architecture | Package | Version | Filename |
|---|---|---|---|---|---|
| ubuntu | 18.04 | noarch | openconnect | < any | UNKNOWN |
| ubuntu | 20.04 | noarch | openconnect | < any | UNKNOWN |
| ubuntu | 22.04 | noarch | openconnect | < any | UNKNOWN |
| ubuntu | 23.10 | noarch | openconnect | < any | UNKNOWN |
| ubuntu | 24.04 | noarch | openconnect | < any | UNKNOWN |
| ubuntu | 16.04 | noarch | openconnect | < any | UNKNOWN |
| ubuntu | 22.04 | noarch | softether-vpn | < any | UNKNOWN |
| ubuntu | 23.10 | noarch | softether-vpn | < any | UNKNOWN |
| ubuntu | 24.04 | noarch | softether-vpn | < any | UNKNOWN |
References
launchpad.net/bugs/cve/CVE-2023-36673
nvd.nist.gov/vuln/detail/CVE-2023-36673
openvpn.net/security-advisory/statement-regarding-tunnelcrack-vulnerabilities/
papers.mathyvanhoef.com/usenix2023-tunnelcrack.pdf
security-tracker.debian.org/tracker/CVE-2023-36673
tunnelcrack.mathyvanhoef.com/details.html
www.cve.org/CVERecord?id=CVE-2023-36673
www.softether.org/9-about/News/905-TunnelCrack
Related
7.3 High
CVSS3
Attack Vector
ADJACENT
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
NONE
CVSS:3.1/AV:A/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N
0.001 Low
EPSS
Percentile
21.5%