CyberGhost - Bug Bounty Program

Rules

CyberGhost

CyberGhost provides secure, encrypted VPN services to millions of users globally. This bug bounty scope includes our web infrastructure, server architecture, and backend services that support CyberGhost's commitment to privacy and data protection.

We invite security researchers to responsibly assess the security posture of our public-facing systems and report any vulnerabilities that may impact user safety or service integrity.

Scope Description

CyberGhost's Web Domains

These domains host our main websites, user interfaces, and account-related features.

Included domains:

• cyberghost.com
• cyberghost.app
• *.cyberghostvpn.com
• *.cyberghost.com

Notes:

• Wildcard includes all subdomains and their children.

CyberGhost APIs

CyberGhost APIs are used across platforms for VPN configuration, account verification, and feature enablement.

• https://api.cyberghostvpn.com

CyberGhost's VPN Servers

CyberGhost operates a secure and private global fleet of VPN servers.

Important notes:

• A full list of server IPs is not publicly shared.
• A representative set of endpoints is discoverable through official apps — only these are considered in-scope.
• Avoid active scanning, brute-force techniques, or any actions that may impact uptime or quality of service.

We welcome responsible testing of endpoints exposed via the official apps that reflect real-world usage.

For any submissions related to our VPN servers, please include a screenshot of the VPN application clearly showing the assigned IP address and location used during testing.

Failure to provide this evidence may result in the report being closed or marked as incomplete.

Browser Extensions

Included assets:

• Chrome Extension
• Firefox Extension

Mobile Applications

Included assets:

• Android App
• iOS App

Desktop Applications

Included assets:

• Windows Application
• macOS Application
• Linux Application

Program Rules

Testing Policy & Responsible Disclosure

Please adhere to the following rules while performing research on this program:

• Denial of service (DoS) attacks on CyberGhost's applications, servers, networks or infrastructure are strictly forbidden.
• Avoid tests that could cause degradation or interruption of our services.
• Do not use automated scanners or tools that generate large amount of network traffic.
• Do not leak, copy, manipulate, or destroy any user data or files in any of our applications/servers.
• No vulnerability disclosure, full, partial or otherwise, is allowed.
• Make sure to apply hunting requirements policy (User-Agent, VPN, etc.)

Reports of Credentials Exposure

In the context of this program, we do not intend to encourage, accept or reward reports of credential exposures that are not applicable to our program’s scope and identified outside of our program’s scope, such as:

• Exposed credentials in/from an out-of-scope asset/source
• Sensitive information exposed in/from an out-of-scope asset/source

To avoid encouraging dark and grey economies (e.g. credential trading, social engineering), we will not accept any report based on information not originating from a failure on our part or that of our service providers.

This includes (but is not limited to):

• Stolen credentials gathered from unidentified sources
• Credentials not applicable and not found in the in-scope assets
• Exposed secrets unrelated to program scope
• PII exposed on out-of-scope assets

Important Precautions and Limitations

As a complement to the Program’s rules and testing policy:

• DO NOT alter compromised accounts by creating, deleting or modifying any data.
• DO NOT use compromised accounts to search for post-auth vulnerabilities (they won’t be eligible anyway).
• DO NOT include Personally Identifiable Information (PII) in your report. REDACT/OBFUSCATE all PII in screenshots or payloads.
• In case of exposed credentials or secrets, limit yourself to verifying the credentials' validity.
• In case of sensitive information leaks, DO NOT extract/copy all data. Only describe and list what's visible.

Reward Eligibility

We are happy to thank everyone who submits valid reports which help us improve the security of CyberGhost. However, only those that meet the following eligibility requirements may receive a monetary reward:

• You must be the first reporter of a vulnerability.
• The vulnerability must be a qualifying vulnerability.
• The report must contain:
  • Clear textual description of the vulnerability
  • Security impact on users and systems
  • Remediation suggestions
  • Proof of exploitation (screenshots, evidence)
  • Reproduction steps (payloads, code, commands)
• You must comply with all testing policy rules.
• You must not be a current or former employee or contractor of CyberGhost.

Reward amounts depend on:

• Reward grid of the relevant scope
• CVSS score and risk impact analysis

Out of scope

• All domains or subdomains not listed in the above list of 'Scopes'

Qualifying vulnerabilities

• SQL Injection (SQLi)
• Cross-Site Scripting (XSS)
• Remote Code Execution (RCE)
• Insecure Direct Object Reference (IDOR)
• Horizontal and vertical privilege escalation
• Authentication bypass & broken authentication
• Business Logic Errors vulnerability with real security impact
• Local files access and manipulation (LFI, RFI, XXE, SSRF, XSPA)
• Cross-Origin Resource Sharing (CORS) with real security impact
• Cross-site Request Forgery (CSRF) with real security impact
• Open Redirect
• Exposed secrets, credentials or sensitive information on an asset under our control and affecting at least one of our scopes
• Cross-site Request Forgery (CSRF) with real security impact
• Remote silent installation of any app
• Other severe logic vulnerabilities that can be exploited remotely
• Privilege escalation vulnerabilities
• Vulnerabilities able to break the site isolation restrictions of a browser
• Arbitrary code execution or silent installation by staging MITM attacks (must demonstrate valid, real MITM)
• Stealing of sensitive information by staging MITM attacks (must demonstrate valid, real MITM)
• UI deception vulnerabilities that may cause actual harm

Non-qualifying vulnerabilities

• Broken Link/Social media Hijacking
• Tabnabbing
• Missing cookie flags
• Content/Text injections
• Clickjacking/UI redressing
• Denial of Service (DoS) attacks
• Recently disclosed CVEs (less than 14 days since patch release)
• CVEs without exploitable vulnerabilities and PoC
• Open ports or services without exploitable vulnerabilities and PoC
• Social engineering of staff or contractors
• Presence of autocomplete attribute on web forms
• Vulnerabilities affecting outdated browsers or platforms
• Self-XSS or XSS that cannot be used to impact other users
• Any hypothetical flaw or best practices without exploitable vulnerabilities and PoC
• SSL/TLS issues (e.g. expired certificates, best practices)
• Unexploitable vulnerabilities (e.g. Self-XSS, XSS or Open Redirect through HTTP headers...)
• Reports with attack scenarios requiring theoretical MITM without demonstration of actual MITM, or physical access to victim's device
• Missing security-related HTTP headers which do not lead directly to an exploitable vulnerability and PoC
• Low severity Cross-Site Request Forgery (CSRF) (e.g. Unauthenticated / Logout / Login / Products cart updates...)
• Invalid or missing email security records (e.g. SPF, DKIM, DMARC)
• Session management issues (e.g. lack of expiration, no logout on password change, concurrent sessions)
• Disclosure of information without exploitable vulnerabilities and PoC (e.g. stack traces, path disclosure, directory listings, software versions, IP disclosure, 3rd party secrets, EXIF Metadata, Origin IP)
• CSV injection
• Malicious file upload (e.g. EICAR files, .EXE)
• HTTP Strict Transport Security Header (HSTS)
• Subdomain takeover without a full exploitable vulnerability and PoC or not applicable to the scope
• Blind SSRF without exploitable vulnerabilities and PoC (e.g. DNS & HTTP pingback, Wordpress XMLRPC)
• Lack or bypass of rate-limiting, brute-forcing or captcha issues
• User enumeration (e.g. email, alias, GUID, phone number, common CMS endpoints)
• Weak password policies (e.g. length, complexity, reuse)
• Ability to spam users (email / SMS / direct messages flooding)
• Disclosed or misconfigured public API keys (e.g. Google Maps, Firebase, analytics tools...)
• Password reset token sent via HTTP referer to external services (e.g. analytics / ads platforms)
• Stolen secrets, credentials or information gathered from a third-party asset that we have no control over
• Exposed secrets, credentials or information on an asset under our control that are not applicable to the program’s scope
• Pre-account takeover (e.g. account creation via oAuth)
• GraphQL Introspection is enabled
• Crashing your own application
• Google API Keys (eg. Analytics, Maps)
• Lack of code obfuscation / binary protection
• Exploiting a generic Android or iOS vulnerability
• Information requiring physical access to user device
• Exploits that are only possible on rooted/jailbroken device
• Exploits that are only possible on iOS version 16 and below
• Exploits that are only possible on Android version 14 and below
• Lack of encryption on internal databases/preference files on mobile device
• Vulnerabilities affecting outdated application binaries - only exploits working on latest Android/iOS versions from the respective app stores will be accepted
• Lack of client-side protections on mobile binaries: SSL pinning/binary protection/code obfuscation/jailbreak detection/root detection/anti-debugging controls/ etc
• Punycode / Unicode confusion account related vulnerabilities without demonstrated impact
• IDOR through unexposed UUIDs