Sitecom Home Storage Center Directory Traversal

`Security Advisory AA-004: Directory Traversal Vulnerability in Sitecom Home Storage Center  
  
Severity Rating: High  
Discovery Date: July 29, 2012  
Vendor Notification: July 30, 2012  
Disclosure Date: September 3, 2012  
  
Vulnerability Type=  
Directory Traversal  
  
Impact=  
- System Access  
- Exposure of sensitive information  
  
Severity=  
Alcyon rates the severity of this vulnerability as high due to the following properties:  
- Ease of exploitation;  
- No authentication credentials required;  
- No knowledge about individual victims required;  
- No interaction with the victim required;  
- Number of Internet connected devices found.  
  
Products and firmware versions affected=  
- Sitecom MD-253 firmware version up to and including 2.4.17  
- Sitecom MD-254 firmware version up to and including 2.4.17  
- Possibly other rebranded Mapower network storage products  
  
Risk Assessment=  
An attacker can read arbitrary files, including the files that stores the administrative password.  
This means an attacer could:  
- Steal sensitive data stored on the device;  
- Leverage the device to drop and/or host malware;  
- Abuse the device to send spam through the victim’s Internet connection;  
- Use the device as a pivot point to access locally connected systems or launch attacks directed to other systems.  
  
Vulnerability=  
The CGI-script that is responsible for showing the device logs is affected by a directory traversal vulnerability that  
  
allows an attacker to view arbitrary files.  
  
Proof of Concept Exploit=  
Paste the following URL into a web browser’s address bar to obtain the administrator’s username and password:  
  
http://<victimIP>/cgi-bin/info.cgi?syslog&../../etc/sysconfig/config/webmaster.conf  
  
Risk Mitigation=  
At the time of disclosure no updated firmware version was available.  
We recommend that you limit access to the devices's web management UI by utilizing proper packet filtering and/or NAT  
  
on your router in order to limit network access to your NAS. Although this will not completely eliminate the risk of  
  
exploitation, it becomes substantially more difficult to leverage a successful attack, because it would involve either  
  
a compromise of another host on the victim’s local network or a client side attack that overcomes the Same Origin  
  
Policy restrictions of the victim’s web browser.  
We provide an installable package for Sitecom devices that enables browser based authentication (Basic Auth) as an  
  
effective workaround for this and future web management UI vulnerabilities. For details refer to  
  
http://www.alcyon.nl/blog/sitecom-nas-md-253-and-md-254-risk-mitigation/  
  
Vendor responses=  
- Sitecom has reported on August 2 that they are working with the manufacturer to verify the vulnerability  
- Sitecom has confirmed on August 28 that the manufacturer is working on a fix  
  
Fixed Versions=  
- There is currently no vendor patch available.  
- A third party patch is provided by Alcyon. See: http://www.alcyon.nl/blog/sitecom-nas-md-253-and-md-254-risk-  
  
mitigation/  
  
=Latest version of this advisory  
http://www.alcyon.nl/advisories/aa-004/  
  
`