Computrols CBAS Web

1. EXECUTIVE SUMMARY

• CVSS v3 8.8
• ATTENTION: Exploitable remotely/low skill level to exploit
• Vendor: Computrols
• Equipment: CBAS Web
• Vulnerabilities: Cross-site Request Forgery, Information Exposure Through Discrepancy, Cross-site Scripting, Command Injection, Information Exposure Through Source Code, Use of Hard-coded Cryptographic Key, SQL Injection, Authentication Bypass Using an Alternate Path or Channel, Inadequate Encryption Strength

2. RISK EVALUATION

Successful exploitation of these vulnerabilities could allow unauthorized actions with administrative privileges, disclosure of sensitive information, execution of code within a user’s browser, execution of unauthorized OS commands, unauthorized access to the database, execution of unauthorized SQL commands, authentication bypass, or decryption of passwords.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

All versions of CBAS Web, a Web Building Management System (BMS), prior to the following versions are affected:
•    19.0.1
•    18.0.1
•    15.0.1
•    14.0.1
•    8.0.7
•    7.2.1-Beta
•    6.9.2
•    4.8.2
•    3.15.1

3.2 VULNERABILITY OVERVIEW

3.2.1    CROSS-SITE REQUEST FORGERY (CSRF) CWE-352

Users can perform certain actions via HTTP requests without performing any validity checks, which may allow unauthorized actions with administrative privileges if a logged-in user visits a malicious website.

CVE-2019-10847 has been assigned to this vulnerability. A CVSS v3 base score of 5.0 has been calculated; the CVSS vector string is (AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:L).

3.2.2    INFORMATION EXPOSURE THROUGH DISCREPANCY CWE-203

The application suffers from a username enumeration weakness. The device behaves differently or sends different responses in a way that may expose security-relevant information about the state of the product.

CVE-2019-10848 has been assigned to this vulnerability. A CVSS v3 base score of 5.3 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N).

3.2.3    IMPROPER NEUTRALIZATION OF INPUT DURING WEB PAGE GENERATION ('CROSS-SITE SCRIPTING') CWE-79

Specific parameters passed to scripts is not sanitized before being returned to the user, which may allow an attacker to execute arbitrary code in a user’s browser session in context of an affected site.

CVE-2019-10846 has been assigned to this vulnerability. A CVSS v3 base score of 5.4 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N).

3.2.4    IMPROPER NEUTRALIZATION OF SPECIAL ELEMENTS USED IN A COMMAND ('COMMAND INJECTION') CWE-77

The application incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component, which could allow attackers to execute commands directly on the operating system.

CVE-2019-10854 has been assigned to this vulnerability. A CVSS v3 base score of 8.8 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H).

3.2.5    INFORMATION EXPOSURE THROUGH SOURCE CODE CWE-540

The application has an unprotected subversion directory, which may allow an attacker to download the entire firmware codebase and discover sensitive information about the inner workings of the underlying OS.

CVE-2019-10849 has been assigned to this vulnerability. A CVSS v3 base score of 7.5 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N).

3.2.6    USE OF HARD-CODED CRYPTOGRAPHIC KEY CWE-321

Several scripts contain a hard-coded encryption key for database backup file decryption, which may allow an authenticated attacker to gain access to the full database of the device and discover sensitive information.

CVE-2019-10851 has been assigned to this vulnerability. A CVSS v3 base score of 6.5 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N).

3.2.7    IMPROPER NEUTRALIZATION OF SPECIAL ELEMENTS USED IN AN SQL COMMAND ('SQL INJECTION') CWE-89

Improper validation of parameters passed to different scripts may allow a remote authenticated attacker to execute arbitrary SQL commands in the application’s database.

CVE-2019-10852 has been assigned to this vulnerability. A CVSS v3 base score of 6.3 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L).

3.2.8    AUTHENTICATION BYPASS USING AN ALTERNATE PATH OR CHANNEL CWE-288

Sending specific parameters to a function will enable the auth flag, which may allow an unauthenticated attacker to bypass authentication and gain full control of the device.

CVE-2019-10853 has been assigned to this vulnerability. A CVSS v3 base score of 8.1 has been calculated; the CVSS vector string is (AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H).

3.2.9    INADEQUATE ENCRYPTION STRENGTH CWE-326

The application stores the passwords in the database using the MD5 hash. The MD5 algorithm is vulnerable to known cryptographic attacks, which may allow discovery of passwords.

CVE-2019-10855 has been assigned to this vulnerability. A CVSS v3 base score of 5.3 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N).

3.3 BACKGROUND

• CRITICAL INFRASTRUCTURE SECTORS: Commercial Facilities, Government Facilities, Healthcare and Public Health 
• COUNTRIES/AREAS DEPLOYED: North America
• COMPANY HEADQUARTERS LOCATION: United States

3.4 RESEARCHER

Gjoko Krstic of Applied Risk reported these vulnerabilities to Computrols.

4. MITIGATIONS

Computrols recommends users upgrade to the following versions or later for each respective major versions of CBAS Web:

• 19.0.1
• 18.0.1
• 15.0.1
• 14.0.1
• 8.0.7
• 7.2.1-Beta
• 6.9.2
• 4.8.2
• 3.15.1

Updated software can be obtained by contacting Computrols Technical Support:

http://www.computrols.com/support/technical-support/

For more information, see the Computrols security advisory at the following link:

http://www.computrols.com/wp-content/uploads/2019/05/CBAS-Web-Advisory-2019-5-9.pdf

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

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

NCCIC also provides a section for control systems security recommended practices on the ICS-CERT web page. Several recommended 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-CERT website in the Technical Information Paper, ICS-TIP-12-146-01B--Targeted Cyber Intrusion Detection and Mitigation Strategies.

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

NCCIC also recommends that users take the following measures to protect themselves from social engineering attacks:

• Do not click web links or open unsolicited attachments in email messages.
• Refer to Recognizing and Avoiding Email Scams for more information on avoiding email scams.
• Refer to Avoiding Social Engineering and Phishing Attacks for more information on social engineering attacks.

No known public exploits specifically target these vulnerabilities.