CVE-2024-3661

HIGH
Published May 6, 2024 Modified Jan 15, 2025 CWE-306 CWE-501

Description

DHCP can add routes to a client’s routing table via the classless static route option (121). VPN-based security solutions that rely on routes to redirect traffic can be forced to leak traffic over the physical interface. An attacker on the same local network can read, disrupt, or possibly modify network traffic that was expected to be protected by the VPN.

CVSS v3.1 Score

7.6
HIGH
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L

Weakness Type (CWE)

CWE-306 Missing Authentication
CWE-501 CWE-501

Affected Products

Vendor Product
fortinet forticlient
fortinet forticlient
fortinet forticlient
fortinet forticlient
fortinet forticlient
fortinet forticlient
cisco anyconnect_vpn_client
cisco secure_client
paloaltonetworks globalprotect
paloaltonetworks globalprotect
paloaltonetworks globalprotect
paloaltonetworks globalprotect
citrix secure_access_client
apple iphone_os
apple macos
citrix secure_access_client
linux linux_kernel
f5 big-ip_access_policy_manager
f5 big-ip_access_policy_manager
f5 big-ip_access_policy_manager
f5 big-ip_access_policy_manager
watchguard ipsec_mobile_vpn_client
watchguard ipsec_mobile_vpn_client
watchguard mobile_vpn_with_ssl
watchguard mobile_vpn_with_ssl
zscaler client_connector
zscaler client_connector
zscaler client_connector
zscaler client_connector

References

Advisories & Patches

https://bst.cisco.com/quickview/bug/CSCwk05814 https://fortiguard.fortinet.com/psirt/FG-IR-24-170 https://my.f5.com/manage/s/article/K000139553 https://security.paloaltonetworks.com/CVE-2024-3661 https://support.citrix.com/article/CTX677069/cloud-software-group-security-advisory-for-cve20243661 https://www.watchguard.com/wgrd-psirt/advisory/wgsa-2024-00009 https://www.zscaler.com/blogs/security-research/cve-2024-3661-k-tunnelvision-exposes-vpn-bypass-vulnerability https://bst.cisco.com/quickview/bug/CSCwk05814 https://fortiguard.fortinet.com/psirt/FG-IR-24-170 https://my.f5.com/manage/s/article/K000139553 https://security.paloaltonetworks.com/CVE-2024-3661 https://support.citrix.com/article/CTX677069/cloud-software-group-security-advisory-for-cve20243661 https://www.watchguard.com/wgrd-psirt/advisory/wgsa-2024-00009 https://www.zscaler.com/blogs/security-research/cve-2024-3661-k-tunnelvision-exposes-vpn-bypass-vulnerability

Exploits

https://arstechnica.com/security/2024/05/novel-attack-against-virtually-all-vpn-apps-neuters-their-entire-purpose/ https://krebsonsecurity.com/2024/05/why-your-vpn-may-not-be-as-secure-as-it-claims/ https://tunnelvisionbug.com/ https://www.theregister.com/2024/05/07/vpn_tunnelvision_dhcp/ https://www.zscaler.com/blogs/security-research/cve-2024-3661-k-tunnelvision-exposes-vpn-bypass-vulnerability https://arstechnica.com/security/2024/05/novel-attack-against-virtually-all-vpn-apps-neuters-their-entire-purpose/ https://krebsonsecurity.com/2024/05/why-your-vpn-may-not-be-as-secure-as-it-claims/ https://tunnelvisionbug.com/ https://www.theregister.com/2024/05/07/vpn_tunnelvision_dhcp/ https://www.zscaler.com/blogs/security-research/cve-2024-3661-k-tunnelvision-exposes-vpn-bypass-vulnerability

Frequently Asked Questions

What is CVE-2024-3661? +
DHCP can add routes to a client’s routing table via the classless static route option (121). VPN-based security solutions that rely on routes to redirect traffic can be forced to leak traffic over the physical interface. An attacker on the same local network can read, disrupt, or possibly modify network traffic that was expected to be protected by the VPN. It has a CVSS v3.1 base score of 7.6 (HIGH).
How severe is CVE-2024-3661? +
CVE-2024-3661 has a CVSS v3.1 score of 7.6 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.
What products are affected by CVE-2024-3661? +
CVE-2024-3661 affects products from apple, cisco, citrix, f5, fortinet, linux, paloaltonetworks, watchguard, zscaler, specifically: anyconnect_vpn_client, big-ip_access_policy_manager, client_connector, forticlient, globalprotect, iphone_os, ipsec_mobile_vpn_client, linux_kernel, macos, mobile_vpn_with_ssl, secure_access_client, secure_client. Check the affected products table above for specific version ranges.
How do I check if I'm vulnerable to CVE-2024-3661? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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