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[R1] Palo Alto Networks PAN-OS /api Multiple Parameter Handling Remote DoS



While developing a plugin to detect PAN-SA-2016-0005, Tenable discovered a different vulnerability in the panUserLogin() function within panmodule.so that could result in an unauthenticated remote DoS. The PAN-OS function calls the glibc strcpy_chk() function to copy a user-supplied username and password to a buffer. If the 'username' parameter exceeds 0x100 bytes or the 'password' parameter exceeds 0x80 bytes, strcpy_chk() causes the process to terminate. When the process terminates, it is re-spawned by its parent process, so it may not be obvious that process had died and may be a partial DoS scenario like previous. However, the log will show it had:

2016-03-19 01:21:34.256 -0400 INFO: appweb: exited, Core: True, Exit signal: SIGABRT
2016-03-19 01:21:48.875 -0400 INFO: appweb: process running with pid 6700
This has been tested on PAN-OS 7.0.1 running on a VM-series firewall.


Palo Alto has released version 7.0.8 and 7.1.0 to address this issue.

Disclosure Timeline

2016-03-21 - Issue discovered
2016-03-22 - Tried to report via Vuln Report page, received "Sorry, an error occurred while processing your request."
2016-03-22 - Tweeted to @PaloAltoNtwks, emailed [email protected] notifying
2016-03-24 - Sent another email asking about broken form
2016-03-27 - Form still broken
2016-04-01 - Form still broken, another tweet sent to @PaloAltoNtwks
2016-04-03 - Two PaloAlto employees reach out after Tweet to help establish contact
2016-04-03 - Report sent directly to Global Security Response Team member
2016-04-03 - PaloAlto GSRT confirms receipt of report
2016-04-04 - Vendor indicates it was found internally, fixed in 7.1.0 released today. Asks if we can confirm.
2016-04-04 - Tenable does not have an active license to get 7.1.0 currently, notifies vendor.
2016-05-17 - Tenable informs vendor, still no access to 7.1.0, asks how to proceed.
2016-05-18 - Vendor says checking with engineering on other supported releases being affected.
2016-05-18 - Tenable researcher got hands on 7.1.0 after all, confirms not vulnerable.
2016-05-20 - Vendor says working on backport to 7.0.8, and evaluating other products affected
2016-05-23 - Vendor confirms only impacted 7.0. PAN-OS 7.0.8 scheduled for June 13th.
2016-06-21 - Vendor releases PAN-OS 7.0.8.
2016-06-27 - Vendor releases formal advisory for the issue.

All information within TRA advisories is provided “as is”, without warranty of any kind, including the implied warranties of merchantability and fitness for a particular purpose, and with no guarantee of completeness, accuracy, or timeliness. Individuals and organizations are responsible for assessing the impact of any actual or potential security vulnerability.

Tenable takes product security very seriously. If you believe you have found a vulnerability in one of our products, we ask that you please work with us to quickly resolve it in order to protect customers. Tenable believes in responding quickly to such reports, maintaining communication with researchers, and providing a solution in short order.

For more details on submitting vulnerability information, please see our Vulnerability Reporting Guidelines page.

If you have questions or corrections about this advisory, please email [email protected]

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