Security Advisory AA-001

Authentication Bypass Vulnerability in Conceptronic Grab’n’Go Network and Sitecom Home Storage Center

Security Advisory AA-002

Password disclosure Vulnerability in Conceptronic Grab’n’Go and Sitecom Home Storage Center

Security Advisory AA-003

Directory Traversal Vulnerability in Conceptronic Grab’n’Go Network Storage (0-day)

Security Advisory AA-004

Directory Traversal Vulnerability in Sitecom Home Storage Center

Security Advisory AA-005

Authorization Bypass Vulnerability in Password Reset Function Conceptronic Grab’n’Go Network Storage (0-day)

Security Advisory AA-006

Authorization Bypass Vulnerability in Password Reset Function Sitecom Home Storage Center

Security Advisory AA-007

Security Advisory AA-007: Arbitrary File Upload Vulnerability in Sitecom Home Storage Center

Security Advisory AA-008

Command Injection Vulnerability in Sitecom Home Storage Center

Responsible Disclosure

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Security Advisory AA-007: Command Injection Vulnerability in Sitecom Home Storage Center

Severity Rating: High
Discovery Date: July 29, 2012
Vendor Notification: July 30, 2012
Disclosure Date: September 12, 2012
Fix Date: September 29, 2012

Vulnerability Type

Command injection

Impact

System access

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.

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 execute commands as the root user. This allows for the download and execution of arbitrary binaries and shell scripts to gain complete control over the device.

Vulnerability

The installer.cgi script allows commands to be injected. A limitation exists in the fact that commands can only exist of characters that are not subject to URL-encoding. However, the hexadecimal representation of the space character (%20) gets properly converted to a space.

Proof of Concept Exploit

Paste the following line into a browser address bar to display the device's admin credentials: 

http://<victimIP>/cgi-bin/installer.cgi?SetExecTable&cat%20/etc/sysconfig/config/webmaster.conf

PoC code exploiting this and other vulnerabilities to obtain an interactive root shell can be found here:

Risk Mitigation

Install the latest firmware version. If you are unable to upgrade you can opt to install our BasicAuth package as a workaround:

We recommend that you limit access to the web management UI of the device by utilizing proper packet filtering and/or NAT on your router in order to limit network access to your NAS. Note that this will not completely eliminate the risk of exploitation, since the product is affected by other vulnerabilities that can be leveraged using client side attacks.

Vendor responses

None

Fixed Versions

  • Firmware version 2.4.21

Latest version of this advisory

References