Trustwave SpiderLabs Uncovers Ov3r_Stealer Malware Spread via Phishing and Facebook Advertising. Learn More

Trustwave SpiderLabs Uncovers Ov3r_Stealer Malware Spread via Phishing and Facebook Advertising. Learn More

Managed Detection & Response

Eliminate active threats with 24/7 threat detection, investigation, and response.

Co-Managed SOC (SIEM)

Maximize your SIEM investment, stop alert fatigue, and enhance your team with hybrid security operations support.

Advisory & Diagnostics

Advance your cybersecurity program and get expert guidance where you need it most.

Penetration Testing

Test your physical locations and IT infrastructure to shore up weaknesses before exploitation.

Database Security

Prevent unauthorized access and exceed compliance requirements.

Email Security

Stop email threats others miss and secure your organization against the #1 ransomware attack vector.

Digital Forensics & Incident Response

Prepare for the inevitable with 24/7 global breach response in-region and available on-site.

Firewall & Technology Management

Mitigate risk of a cyberattack with 24/7 incident and health monitoring and the latest threat intelligence.

Microsoft Exchange Server Attacks
Stay protected against emerging threats
Rapidly Secure New Environments
Security for rapid response situations
Securing the Cloud
Safely navigate and stay protected
Securing the IoT Landscape
Test, monitor and secure network objects
Why Trustwave
About Us
Awards and Accolades
Trustwave SpiderLabs Team
Trustwave Fusion Security Operations Platform
Trustwave Security Colony
Technology Alliance Partners
Key alliances who align and support our ecosystem of security offerings
Trustwave PartnerOne Program
Join forces with Trustwave to protect against the most advance cybersecurity threats
SpiderLabs Blog

Credential Leak Flaws in Windows PureVPN Client

Using a VPN (Virtual Private Network) can bring many advantages, particularly when you want to access remote resources, or you are using a network you don't fully trust, for example, a coffee shop or an airport.

In the recent years, there has been a rise in the number of VPN providers targeting users who may not be technically savvy but still want to use a VPN to improve the security of their connections, are concerned about privacy or want to bypass some geographical restriction.

One of the main features such providers offer is that it's really easy to set up a VPN. Just a couple of clicks, a straightforward configuration and you are ready to go. Since they want to make it easy for users, most of the clients offer to store the password so you can connect with a click (or even do it automatically each time your laptop starts).

I had some curiosity regarding the "stored password" functionality, so I started digging, and I found two vulnerabilities. We disclosed these vulnerabilities to PureVPN as part of our Responsible Disclosure program. They accepted the risk of the first one and provided a patch for the second. The details can be found in the advisory TWSL2018-010.

I tested for these vulnerabilities under the following assumptions and conditions:

  • The PureVPN client has a default installation.
  • The attacker has access to any local user account.
  • Someone has successfully logged in to the PureVPN using the client on a Windows machine at any point in time.
  • The Windows machine has more than one user in the case of disclosing another users credentials in a multiuser environment.

The vulnerabilities were found in version of the PureVPN Windows client and disclosed to the vendor. The vendor has released a patch. We've tested version 6.1.0, and it's no longer vulnerable.

I'll explain each of the vulnerabilities I found:

Vulnerability #1 – Password revealed in Client's Configuration Window

Not Fixed. The vendor accepted the risk.


The PureVPN Windows Client provided by PureVPN may allow a local attacker to retrieve the stored password of the last user who successfully logged in to the PureVPN service. Because of this, a local attacker may obtain another user's PureVPN credentials when a Windows machine has multiple users if they have successfully logged in. The attack is done exclusively through the GUI (Graphical User Interface), there's no need to use an external tool.


Steps to obtain the password:

  1. Open the PureVPN Windows Client.
  2. Go to Configuration
  3. Open the "User Profile" tab
  4. Click on "Show Password"



Figure 1. Configuration tab with information about the login


Figure 2. Configuration tab with the credentials

Vulnerability #2 – Plaintext storage of PureVPN Windows Client Credentials



The PureVPN Windows Client stores the Login Credentials (username and password) in plaintext. The location of such files is: 'C:\ProgramData\purevpn\config\login.conf'

Additionally, all local users can read this file.



Steps to obtain the password:

  1. Read the file in 'C:\ProgramData\purevpn\config\login.conf'



Figure 3. Location and content of the file with the credentials in plaintext


Figure 4. Permissions of the file with the credentials in plaintext

Finally, some recommendations are:

  • In case you use the PureVPN for Windows, verify you are running the latest version, if not update.
  • Never reuse password between services.
  • Whenever possible, enable two-factor authentication.

To help you test for the presence of this vulnerability, I also created a Metasploit module that you can access here:

Latest SpiderLabs Blogs

Welcome to Adventures in Cybersecurity: The Defender Series

I’m happy to say I’m done chasing Microsoft certifications (AZ104/AZ500/SC100), and as a result, I’ve had the time to put some effort into a blog series that hopefully will entertain and inform you...

Read More

Trustwave SpiderLabs: Insights and Solutions to Defend Educational Institutions Against Cyber Threats

Security teams responsible for defending educational institutions at higher education and primary school levels often find themselves facing harsh lessons from threat actors who exploit the numerous...

Read More

Breakdown of Tycoon Phishing-as-a-Service System

Just weeks after Trustwave SpiderLabs reported on the Greatness phishing-as-a-service (PaaS) framework, SpiderLabs’ Email Security team is tracking another PaaS called Tycoon Group.

Read More