abraxas/pfsense-pppoe-cronpfSense CE 2.9.0-DEVELOPMENT - High - Remote - RCE - PPPoE ptpid crontab
abraxaslabs.tech · github.com/abraxas · @abraxas_null · [email protected] · pfsense-pppoe-cron
Class: RCE Reach: Remote
pfSense CE 2.9.0-DEVELOPMENT (9363ac5) - pfsense.org
handle_pppoe_reset uses hidden ptpid without is_numericint. Custom hour/minute validation is AND where it needed OR. configure_cron writes fields raw. Sibling of SA-26_06, not proxyuser.
| 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-interfaces-ppps-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 127.0.0.1:18970.
Series write-up: https://abraxaslabs.tech/research/pfsense-ce-leftovers
| Method | Sink | Privilege |
|---|---|---|
| POST interfaces_ppps_edit.php ptpid / pppoe_resethour | handle_pppoe_reset then configure_cron raw fields | Integrity: Lab-proven: newline in ptpid added an extra root crontab line; stub cron executed it. |
| same leftover | same sink | Recon: Inferred: extra cron as root. |
| same leftover | same sink | Availability: Inferred: extra periodic commands. |
Requires: page-interfaces-ppps-edit. CSRF-magic on POST unless noted. WebGUI PHP-FPM is root.
Requires: page-interfaces-ppps-edit. CSRF-magic on POST unless noted. WebGUI PHP-FPM is root. CSRF-magic on POST unless noted. WebGUI PHP-FPM is root.
SA-26_06 is System Proxy crontab. #16128 is PPP client sanitize.
No Diagnostics: Command unless that page is also granted.
cd lab
./run.sh
Loopback 127.0.0.1:18970. Compose project pfsense-pppoe-cron. Witness PFSENSE-PPPOE-CRON-WITNESS. Loopback only: 127.0.0.1:18970. Compose project pfsense-pppoe-cron. Witness PFSENSE-PPPOE-CRON-WITNESS. PHP gadget of the pinned lines. Stack tears down after the run.
Last line:
SUCCESS PFSENSE-PPPOE-CRON control-one-line=yes trigger-extra-root-line=yes stub-cron-ran-extra=yes PFSENSE-PPPOE-CRON-WITNESS
is_numericint ptpid. Reject CR/LF in hour/minute. Quote crontab fields.
9363ac5b8651a1c7a333180425ce7719070f95f9