abraxas/pfsense-l2tp-radius-mpdpfSense CE 2.9.0-DEVELOPMENT - High - Remote - RCE - L2TP RADIUS mpd.conf
abraxaslabs.tech · github.com/abraxas · @abraxas_null · [email protected] · pfsense-l2tp-radius-mpd
Class: RCE Reach: Remote
pfSense CE 2.9.0-DEVELOPMENT (9363ac5) - pfsense.org
vpn.inc interpolates "{$radiussecret}" quoted but unescaped. PPP client uses get_mpd_str(); servers do not. Extra set iface up-script wins. #16128 is client-only.
| ID | no CVE yet |
| Class | RCE |
| Reach | Remote (authenticated WebGUI unless noted) |
| CWE | CWE-78 |
| CVSS | High: 8.8 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
| Product | pfSense CE |
| Affected | 2.9.0-DEVELOPMENT (9363ac5b8651a1c7a333180425ce7719070f95f9) |
| Auth | WebGUI session with page-vpn-vpnl2tp (sibling page-services-pppoeserver-edit) |
| License | GNU Affero GPL v3.0 |
| Lab | 127.0.0.1 only |
I pinned public master 9363ac5. The lab is a PHP gadget of the pinned sink, loopback HTTP on 127.0.0.1:18960.
Series write-up: https://abraxaslabs.tech/research/pfsense-ce-leftovers
| Method | Sink | Privilege |
|---|---|---|
| POST vpn_l2tp.php radius secret | vpn.inc set radius server ... "{$radiussecret}" | Integrity: Lab-proven: quote-close secret added set iface up-script; stub mpd last-wins ran it and wrote the witness. get_mpd_str absent on this path. |
| same leftover | same sink | Recon: Inferred: up-script runs as root on the next L2TP session. |
| same leftover | same sink | Availability: Inferred: break mpd parse / VPN service. |
Requires: page-vpn-vpnl2tp (sibling page-services-pppoeserver-edit). CSRF-magic on POST unless noted. WebGUI PHP-FPM is root.
Requires: page-vpn-vpnl2tp (sibling page-services-pppoeserver-edit). CSRF-magic on POST unless noted. WebGUI PHP-FPM is root. CSRF-magic on POST unless noted. WebGUI PHP-FPM is root.
PPP client get_mpd_str already on this pin. CONTROL secret does not write witness.
No Diagnostics: Command unless that page is also granted.
cd lab
./run.sh
Loopback 127.0.0.1:18960. Compose project pfsense-l2tp-radius-mpd. Witness PFSENSE-L2TP-RADIUS-MPD-WITNESS. Loopback only: 127.0.0.1:18960. Compose project pfsense-l2tp-radius-mpd. Witness PFSENSE-L2TP-RADIUS-MPD-WITNESS. PHP gadget of the pinned lines. Stack tears down after the run.
Last line:
SUCCESS PFSENSE-L2TP-RADIUS-MPD control-quoted-secret=1 control-extra-up-script=no control-witness=no trigger-extra-up-script=yes trigger-last-wins=yes trigger-witness=yes get_mpd_str=no PFSENSE-L2TP-RADIUS-MPD-WITNESS
Run RADIUS secrets through get_mpd_str on L2TP and PPPoE server configure.
9363ac5b8651a1c7a333180425ce7719070f95f9