Black Box KVM

1. EXECUTIVE SUMMARY

• CVSS v3 7.5
• ATTENTION: Low attack complexity/public exploits are available
• Vendor: Black Box 
• Equipment: KVM Switches and Extenders
• Vulnerability: Path Traversal

2. RISK EVALUATION

Successful exploitation of this vulnerability could allow an attacker to read sensitive data on the built-in web servers of the affected devices.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

The following models and versions of Black Box KVMs, a Keyboard/Video/Mouse switch and extender, are affected:

• Black Box KVM ACR1000A-R-R2: Firmware version v3.4.31307
• Black Box KVM ACR1000A-T-R2: Firmware version v3.4.31307
• Black Box KVM ACR1002A-T: Firmware version v3.4.31307
• Black Box KVM ACR1002A-R: Firmware version v3.4.31307
• Black Box KVM ACR1020A-T: Firmware version v3.4.31307
  
   

3.2 VULNERABILITY OVERVIEW

3.2.1 IMPROPER LIMITATION OF A PATHNAME TO A RESTRICTED DIRECTORY ('PATH TRAVERSAL') CWE-22

Black Box KVM Firmware version 3.4.31307 on models ACR1000A-R-R2, ACR1000A-T-R2, ACR1002A-T, ACR1002A-R, and ACR1020A-T is vulnerable to path traversal, which may allow an attacker to steal user credentials and other sensitive information through local file inclusion.

CVE-2022-4636 has been assigned to this vulnerability. A CVSS v3 base score of 7.5 has been assigned; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N).

3.3 BACKGROUND

• CRITICAL INFRASTRUCTURE SECTORS: Multiple
• COUNTRIES/AREAS DEPLOYED: Worldwide
• COMPANY HEADQUARTERS LOCATION: India

3.4 RESEARCHER

CISA discovered a public Proof of Concept (PoC) as authored by Ferhat Çil and reported it to Black Box.

4. MITIGATIONS

Black Box has provided an update to the firmware to mitigate this vulnerability and recommends all users update products to the latest versions:

• Black Box KVM ACR1000A-R-R2: Update to firmware v3.6 or later
• Black Box KVM ACR1000A-T-R2: Update to firmware v3.6 or later
• Black Box KVM ACR1002A-T: Update to firmware v3.6 or later
• Black Box KVM ACR1002A-R: Update to firmware v3.6 or later
• Black Box KVM ACR1020A-T: Update to firmware v3.6 or later

Black Box recommends users seek advice from third-party equipment or software package(s) vendors to evaluate if this vulnerability impacts third-party equipment/software.

CISA recommends users take defensive measures to minimize the risk of exploitation of this vulnerability. Specifically, users should:

• Minimize network exposure for all control system devices and/or systems, and ensure they are not accessible from the Internet.
• Locate control system networks and remote devices behind firewalls and isolate them from business networks.
• When remote access is required, use secure methods, such as Virtual Private Networks (VPNs), recognizing VPNs may have vulnerabilities and should be updated to the most current version available. Also recognize VPN is only as secure as its connected devices.

CISA reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures.

CISA also provides a section for control systems security recommended practices on the ICS webpage at cisa.gov/ics. Several CISA products detailing cyber defense best practices are available for reading and download, including Improving Industrial Control Systems Cybersecurity with Defense-in-Depth Strategies.

Additional mitigation guidance and recommended practices are publicly available on the ICS webpage at cisa.gov/ics in the technical information paper, ICS-TIP-12-146-01B--Targeted Cyber Intrusion Detection and Mitigation Strategies.

Organizations observing suspected malicious activity should follow established internal procedures and report findings to CISA for tracking and correlation against other incidents.

This vulnerability is not exploitable remotely. 

• Black Box