Skyhigh Client Proxy Security Bulletin

Vulnerabilities Fixed

This Skyhigh Client Proxy release includes updates addressing publicly disclosed CVEs, regardless of whether a CVE has been shown to impact users.
The following medium-level CVEs (CVSS 3.1 >= 5.5) were involved: 

CVE	Description
CVE-2024-0311	Attackers can bypass the policy of Skyhigh Client Proxy without a valid release code.   https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2024-0311     https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2024-0311
CVE-2024-0312	The attacker can uninstall Skyhigh Client Proxy without a valid uninstall password.  https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2024-0312     https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2024-0312
CVE-2024-0313	The Client Proxy service allows you to monitor employee network activity and prevent data exfiltration and malware downloads. A malicious insider exploiting this vulnerability can circumvent existing security controls and defeat DLP policies put in place by the organization.  On the contrary, if the victim is legitimately using the temporary bypass to reach out to the Internet to retrieve application and system updates, a remote device could target it and undo the bypass, thereby denying the victim access to the update service and causing it to fail.  https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2024-0313     https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2024-0313

Remediation 

To remediate this issue, 

• If you are using an earlier version of Skyhigh Client Proxy, upgrade to version 4.9.0.
• Go to the Download Software site and download the applicable product upgrade or hotfix files: Download Skyhigh Client Proxy 

Product Specific Notes 

• Supported Windows Installer 

In the 4.9.0 release version of Skyhigh Client Proxy, there is support available only for 64-bit Windows installers. For details, see Client Proxy 4.9.0 Release Notes.  

Mitigations 

Skyhigh Client Proxy must be upgraded to version 4.9.0. 

Acknowledgments 

Trellix/Skyhigh Security credits smkb (smkb@smokingbit.com) for responsibly reporting CVE-2024-0311 and CVE-2024-0312 and Winston Ho (@violenttestpen) or responsibly reporting CVE-2024-0313. 

Frequently Asked Questions (FAQs) 

1. How do I know if my product is vulnerable or not? 

For Endpoint Security (ENS) on Windows: 

1. Use the following instructions for endpoint or client based products: 
2. Right-click on the Trellix tray shield icon on the Windows taskbar.  
3. Select Endpoint Security  
4. In the console, select Action Menu.  
5. In the Action Menu, select About. The product version is displayed. 

For other Endpoint products and ENS on other platforms: 

Use the following instructions for endpoint or client based products: 

1. Right-click on the Trellix tray shield icon on the Windows taskbar.  
2. Select Open Console.  
3. In the console, select Action Menu.  
4. In the Action Menu, select Product Details. The product version is displayed. 

For ePO/Server products: 

Use the following instructions for server-based products: 

• Check the version and build of ePO that is installed. For information on how to check the version, see: KB52634. 
• Create a query in ePO for the product version of the product installed within your organization. 

For Appliances: 

Use the following instructions for Appliance based products: 

1. Open the Administrator's User Interface (UI). 
2. Click the About link. The product version is displayed. 

For DLPe ePO Extension: 

Use the following instructions: 

2. Log on to your ePO server.  
3. Click Menu, Data Protection, DLP Policy. 
4. Inside the DLP console click Help, About. The product version is displayed. 

 

2. What is CVSS? 

CVSS, or Common Vulnerability Scoring System, is the result of the National Infrastructure Advisory Council’s effort to standardize a system of assessing the criticality of a vulnerability. This system offers an unbiased criticality score between 0 and 10 that users can use to judge how critical a vulnerability is and plan accordingly. For more information, please visit the CVSS website at: https://www.first.org/cvss/. 

When calculating CVSS scores, we have adopted a philosophy that fosters consistency and repeatability. Our guiding principle for CVSS scoring is to score the exploit under consideration by itself. We consider only the immediate and direct impact of the exploit under consideration. We do not factor into a score any potential follow-on exploits that might be made possible by the successful exploitation of the issue being scored. 

3. What are the CVSS scoring metrics? 
   1. CVE-2024-0311: API Hooking in leading to Challenge/Response Bypass for Unlimited Time 

Base Score	5.5
Attack Vector (AV)	Local (L)
Attack Complexity (AC)	Low (L)
Privileges Required (PR)	Low (L)
User Interaction (UI)	None (N)
Scope (S)	Unchanged (U)
Confidentiality (C)	None (N)
Integrity (I)	High (H)
Availability (A)	None (N)
Temporal Score (Overall)	5.0
Exploitability (E)	Proof-of-Concept (P)
Remediation Level (RL)	Official Fix (O)
Report Confidence (RC)	Confirmed (C)

2. CVE-2024-0312: API Hooking in leading to Uninstaller Challenge/Response Bypass 

Base Score	5.5
Attack Vector (AV)	Local (L)
Attack Complexity (AC)	Low (L)
Privileges Required (PR)	Low (L)
User Interaction (UI)	None (N)
Scope (S)	Unchanged (U)
Confidentiality (C)	None (N)
Integrity (I)	High (H)
Availability (A)	None (N)
Temporal Score (Overall)	5.0
Exploitability (E)	Proof-of-Concept (P)
Remediation Level (RL)	Official Fix (O)
Report Confidence (RC)	Confirmed (C)

3. CVE-2024-0313: Unrestricted Client Proxy Policy Bypass via Release Code Enforcement Bypass 

Base Score	5.5
Attack Vector (AV)	Local (L)
Attack Complexity (AC)	Low (L)
Privileges Required (PR)	Low (L)
User Interaction (UI)	None (N)
Scope (S)	Unchanged (U)
Confidentiality (C)	None (N)
Integrity (I)	High (H)
Availability (A)	None (N)
Temporal Score (Overall)	5.0
Exploitability (E)	Proof-of-Concept (P)
Remediation Level (RL)	Official Fix (O)
Report Confidence (RC)	Confirmed (C)

4. Where can I find a list of all Security Bulletins?  

All Security Bulletins are published on our external Support website at https://supportm.trellix.com/webcenter/portal/supportportal/pages_knowledgecenter?s=true&lang=en-us&sm=false&tab=SCtdl&facets=Security+Bulletin@INQUIRA_TYPE&sb=mostRecent&sbv=Date&scps=q  Security Bulletins are retired (removed) once a product is both End of Sale and End of Support (End of Life).   

5. How do I report a product vulnerability to Trellix or Skyhigh Security?  

If you have information about a security issue or vulnerability with a Trellix or Skyhigh Security product, please visit the PSIRT website for instructions at https://kcm.trellix.com/corporate/index?page=content&id=KB95563  

6. How does Trellix & Skyhigh Security respond to this and any other reported security flaws?  

Our key priority is the security of our users.  If a vulnerability is found within any of our software or services, we work closely with the relevant security software development team to ensure the rapid and effective development of a fix and communication plan.  

Trellix/Skyhigh Security only publish security bulletins if they include something actionable such as a workaround, mitigation, version upgrade, update, or hotfix; otherwise we would simply be informing the hacker community that our products are a target, putting our users at greater risk.  For products that are updated automatically, a non-actionable security bulletin may be published to acknowledge the discoverer.  

View our PSIRT policy on the Support website at https://kcm.trellix.com/corporate/index?page=content&id=KB95564     

Resources 

To contact Technical Support, log on to the ServicePortal and go to the Create a Service Request page at https://supportm.trellix.com/webcenter/portal/supportportal/pages_serviceRequests&Adf-Window-Id=w63qdurtt5&lang=en_US : 

• If you are a registered user, type your User Id and Password, and then click Log In. 

• If you are not a registered user, click Register and complete the required fields. Your password and login instructions will be emailed to you. 

Disclaimer 

The information provided in this Security Bulletin is provided as is without warranty of any kind. Skyhigh Security disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Skyhigh Security or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Skyhigh Security or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages, so the preceding limitation may not apply. 

Any future product release dates mentioned in this bulletin are intended to outline our general product direction, and they should not be relied on in making a purchasing decision. The product release dates are for information purposes only and may not be incorporated into any contract. The product release dates are not a commitment, promise, or legal obligation to deliver any material, code, or functionality. The development, release, and timing of any features or functionality described for our products remain at our sole discretion and may be changed or canceled at any time.