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Reporting security vulnerabilities

Please report your finding using the form below. Upon receiving your report, we will investigate and respond to you as soon as possible. Please do not discuss any vulnerabilities (even resolved ones) outside of the program without express consent from the organization.

Alternatively you can send an email to security@larksuite.com. Participation in our bug bounty program requires complying with the full bug bounty policy below.

Bug bounty policy

Disclosure Policy and Rules

  • As this is a private program, please do not discuss this program or any vulnerabilities (even resolved ones) outside of the program without express consent from the organization.
  • Follow HackerOne's disclosure guidelines.

Program Rules

  • You must be the first reporter to report the issue to us. We will only reward the first reporter.
  • When submitting a vulnerability, please provide us with enough information so that we can reproduce and verify it.
  • Please use your own account for testing purposes. Do not gain access to another user's account or their confidential information.
  • Please do not test for denial of service, spam, social engineering issues.
  • All of the tests must not violate any law, or compromise any data that is not your own.
  • Please contact security@larksuite.com to report security incidents such as customer data leakage or breach of infrastructure
  • Please provide detailed reports with reproducible steps. If the report is not detailed enough to reproduce the issue, the issue will not be eligible for a reward.
  • Submit one vulnerability per-report, unless you need to chain vulnerabilities to provide impact.
  • When duplicates occur, we only award the first report that was received (provided that it can be fully reproduced).
  • Multiple vulnerabilities caused by one underlying issue will be awarded one bounty.
  • We discourage the use of vulnerability testing tools or other tools that generate significant volumes of traffic; using these tools may disqualify you from qualifying for a reward.

Not eligible for reward

When reporting vulnerabilities, please consider (1) attack scenario / exploitability, and (2) security impact of the bug. The following issues are considered out of scope:

Out of scope bugs

  • Reports from automated tools or scans
  • Spam vulnerability, mail spoofing, mail bomb, etc.
  • Self-XSS
  • Use of known-vulnerable library or component
  • Clickjacking on pages with no sensitive actions
  • Cross-Site Request Forgery (CSRF) on unauthenticated forms or forms with no sensitive actions
  • Attacks requiring MITM or physical access to a user's device.
  • Previously known vulnerable libraries without a working Proof of Concept.
  • Comma Separated Values (CSV) injection without demonstrating a vulnerability.
  • Missing best practices in SSL/TLS configuration.
  • Any activity that could lead to the disruption of our service (DoS).
  • Content spoofing and text injection issues without showing an attack vector/without being able to modify HTML/CSS
  • Rate limiting or bruteforce issues on non-authentication endpoints
  • Missing best practices in Content Security Policy.
  • Missing HttpOnly or Secure flags on cookies
  • Missing email best practices (Invalid, incomplete or missing SPF/DKIM/DMARC records, etc.)
  • Vulnerabilities only affecting users of outdated or unpatched browsers [Less than 2 stable versions behind the latest released stable version]
  • Software version disclosure / Banner identification issues / Descriptive error messages or headers (e.g. stack traces, application or server errors).
  • Public Zero-day vulnerabilities that have had an official patch for less than 1 month will be awarded on a case by case basis.
  • Tabnabbing
  • Open redirect - unless an additional security impact can be demonstrated
  • Issues that require unlikely user interaction
  • Vulnerabilities that are already known (e.g. discovered by an internal team)
  • Best practice" reports are not eligible for bounties but are appreciated.

Out of Scope bugs for Android apps

  • Any URIs leaked because a malicious app has permission to view URIs opened
  • Sensitive data in URLs/request bodies when protected by TLS
  • Lack of obfuscation and binary protection
  • Any kind of sensitive data stored in app private directory
  • Runtime hacking exploits using tools like but not limited to Frida/ Appmon (exploits only possible in a jailbroken environment & root permission)
  • Shared links leaked through the system clipboard.
  • Intent or URL Redirection leading to phishing
  • Third party library 0day

Out of Scope bugs for iOS apps

  • Lack of Exploit mitigations i.e., PIE, ARC, or Stack Canaries
  • Absence of certificate pinning
  • Path disclosure in the binary
  • User data stored unencrypted in the app private directory
  • Lack of obfuscation is out of scope
  • Lack of jailbreak detection is out of scope
  • OAuth & app secret hard-coded/recoverable in IPA
  • Crashes due to malformed URL Schemes
  • Lack of binary protection (anti-debugging) controls
  • Snapshot/Pasteboard leakage
  • Runtime hacking exploits using tools like but not limited to Frida/ Appmon (exploits only possible in a jailbroken environment)
  • Third party library 0day is out of scope
  • URL Redirection leading to phishing