MitM attack in Fortinet FortiClient
| Risk | Medium |
| Patch available | YES |
| Number of vulnerabilities | 1 |
| CVE-ID | CVE-2024-3661 |
| CWE-ID | CWE-300 |
| Exploitation vector | Local network |
| Public exploit | N/A |
| Vulnerable software Subscribe |
Fortinet FortiClient for Windows Server applications / Other server solutions FortiClient (Linux) Client/Desktop applications / Software for system administration FortiClient (macOS) Client/Desktop applications / Software for system administration |
| Vendor | Fortinet, Inc |
Security Bulletin
This security bulletin contains one medium risk vulnerability.
1) Man-in-the-Middle (MitM) attack
EUVDB-ID: #VU91755
Risk: Medium
CVSSv3.1: 4.4 [CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L/E:U/RL:O/RC:C]
CVE-ID: CVE-2024-3661
CWE-ID:
CWE-300 - Channel Accessible by Non-Endpoint ('Man-in-the-Middle')
Exploit availability: No
DescriptionThe vulnerability allows a remote attacker to perform MitM attack.
The vulnerability exists due to way the VPN client handles routes advertised by the DHCP server. A remote attacker with access to the local network can route the victim's traffic to a malicious server instead of sending it via a secured channel.
Install updates from vendor's website.
Vulnerable software versionsFortinet FortiClient for Windows: 0 - 7.2.4
FortiClient (Linux): 6.0.0 - 7.2.4
FortiClient (macOS): 5.6.6 - 7.2.4
External linkshttp://datatracker.ietf.org/doc/html/rfc2131#section-7
http://datatracker.ietf.org/doc/html/rfc3442#section-7
http://tunnelvisionbug.com/
http://www.leviathansecurity.com/research/tunnelvision
http://news.ycombinator.com/item?id=40279632
http://arstechnica.com/security/2024/05/novel-attack-against-virtually-all-vpn-apps-neuters-their-entire-purpose/
http://krebsonsecurity.com/2024/05/why-your-vpn-may-not-be-as-secure-as-it-claims/
http://issuetracker.google.com/issues/263721377
http://mullvad.net/en/blog/evaluating-the-impact-of-tunnelvision
http://www.zscaler.com/blogs/security-research/cve-2024-3661-k-tunnelvision-exposes-vpn-bypass-vulnerability
http://lowendtalk.com/discussion/188857/a-rogue-dhcp-server-within-your-network-can-and-will-hijack-your-vpn-traffic
http://news.ycombinator.com/item?id=40284111
http://www.agwa.name/blog/post/hardening_openvpn_for_def_con
http://www.theregister.com/2024/05/07/vpn_tunnelvision_dhcp/
http://www.fortiguard.com/psirt/FG-IR-24-170
Q & A
Can this vulnerability be exploited remotely?
Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the local network (LAN).
Is there known malware, which exploits this vulnerability?
No. We are not aware of malware exploiting this vulnerability.
