ASUS RP-AC52 contains multiple vulnerabilities
Original Release date: 17 Oct 2016 | Last revised: 28 Oct 2016

Overview
The ASUS RP-AC52 access point, firmware version 1.0.1.1s and possibly earlier, is vulnerable to cross-site request forgery and command injection.

Description

CWE-352: Cross-Site Request Forgery (CSRF) CVE-2016-6557
The RP-AC52 web interface does not sufficiently verify whether a valid request was intentionally provided by the user.

An attacker can perform actions with the same permissions as a victim user, provided the victim has an active session and is induced to trigger the malicious request.CWE-77: Improper Neutralization of Special Elements used in a Command (‘Command Injection’) CVE-2016-6558A command injection vulnerability exists in apply.cgi on the RP-AC52 web interface specifically in the action_script parameter.

The action_script parameter specifies a script to be executed if the action_mode parameter does not contain a valid state.
If the input provided by action_script does not match one of the hard coded options, then it will be executed as the argument of either a system() or an eval() call allowing arbitrary commands to be executed.The most recent version of the RP-AC52 firmware, version 1.0.1.1s, has been confirmed vulnerable by the researcher.
Source code analysis would indicate that earlier versions are vulnerable as well.Based on a source code analysis of firmware version 1.0.1.1q the following devices are also suspected to be vulnerable:EA-N66RP-N12RP-N14RP-N53RP-AC56WMP-N12The CVSS score below reflects CVE-2016-6557.

Impact

A remote, unauthenticated attacker may be able to trick an authenticated user into clicking a specially crafted link, resulting in settings modification, privilege escalation, or complete control of the system.

Solution

Apply an updateThe vendor has released firmware updates for the RP-N12, RP-N12, RP-AC52, RP-N53, EA-N66, RP-AC56 devices to address the issues.The WMP-N12 will not be receiving an update.If you are unable to apply an update, please consider the following workarounds:

Restrict access and use strong passwordsLAN hosts should not browse the Internet while the web management interface has an active session in a browser tab.

As a general good security practice, only allow trusted hosts to connect to the LAN.
Implement strong passwords for WiFi and for the web management interface.
Strong passwords can help to prevent blind guessing attempts that would establish sessions for CSRF attacks.

Vendor Information (Learn More)
Vendor
Status
Date Notified
Date Updated
AsusTek Computer Inc.
Affected
30 Aug 2016
12 Oct 2016
If you are a vendor and your product is affected, let us know.
CVSS Metrics (Learn More)
Group
Score
Vector
Base
9.3
AV:N/AC:M/Au:N/C:C/I:C/A:C
Temporal
8.0
E:POC/RL:W/RC:ND
Environmental
6.0
CDP:N/TD:M/CR:ND/IR:ND/AR:ND

References

Credit
Thanks to Ian Smith for reporting these vulnerabilities.
This document was written by Trent Novelly.

Other Information
CVE IDs: CVE-2016-6557 CVE-2016-6558
Date Public: 17 Oct 2016
Date First Published: 17 Oct 2016
Date Last Updated: 28 Oct 2016
Document Revision: 16

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