#NahamCon2023: Bugs Exposed: Unveiling Effective Strategies for Bug Bounty Programs | @ArchAngelDDay

Summary

In this insightful talk, Douglas Day shares key strategies for bug bounty programs, focusing on identifying critical vulnerabilities through a structured approach. He emphasizes the importance of analyzing 'no's' in applications, mapping out role-based access control (RBAC) systems, and targeting user management features like invites. Douglas highlights practical examples of common vulnerabilities, such as account takeovers, privilege escalation through invite systems, and the exploitation of poorly configured email invite functionality. His methodical approach and quick identification of bugs provide valuable insights for both new and experienced security researchers.

Takeaways

• 😀 Focus on finding 'no's' (restrictions, trust boundaries) rather than common vulnerabilities like XSS or SQLi.
• 😀 A 'no' refers to an application’s security control or restriction that can be bypassed to exploit the system.
• 😀 Mapping out a role-based access control (RBAC) matrix helps identify privilege escalation opportunities.
• 😀 The first 30 minutes of testing should focus on user management, particularly the invite functionality.
• 😀 Invite functionality can expose user information such as full names or emails before the invite is accepted.
• 😀 Exploiting invite functionality can lead to privilege escalation or account hijacking if roles are not properly enforced.
• 😀 Try modifying invite links or IDs to access other users’ organizations and escalate your privileges.
• 😀 Look for expired or cancelled invites that still allow users to rejoin the organization, which can be a vulnerability.
• 😀 In user invites, check for vulnerabilities in role manipulation, such as changing a user’s role to gain higher permissions.
• 😀 HTML injection in invite emails is a common low-severity vulnerability but can still be exploited for malicious purposes.

Q & A

What is the primary focus of the speaker during the first 30 minutes of testing a new SaaS application?

The speaker focuses on user management, specifically the invite functionality, as it presents various potential vulnerabilities like IDOR (Insecure Direct Object References), account takeovers, and role escalation issues.

Why does the speaker prioritize testing the invite functionality in SaaS applications?

The invite functionality is often a low-hanging fruit for finding critical vulnerabilities, such as exposing personal user information, allowing users to invite others without approval, or enabling unauthorized actions through invite-related flaws.

What are some common vulnerabilities related to the invite functionality?

Common vulnerabilities include exposing personal information like full names, enabling unauthorized users to join organizations, failing to expire invites after users are removed, and allowing modification of invite roles to escalate permissions.

Can you explain how an account takeover could occur through the invite functionality?

An attacker could invite a user to their organization, then as an admin, modify the user's email address. This would allow the attacker to reset the password and take over the account without the user’s consent.

What is RBAC (Role-Based Access Control), and why is it important in bug hunting?

RBAC defines user permissions based on roles, such as admin, manager, or user. It's important because improper implementation can lead to privilege escalation, where users gain more access than they should, potentially compromising the system.

How does the speaker identify potential privilege escalation issues?

The speaker creates an RBAC matrix, maps out the roles and their permissions, and tests different user actions to check if lower-level users can perform actions that should be restricted to higher-level users, such as deleting data or modifying roles.

What does the speaker mean by testing for 'No’s'?

'No’s' refer to restrictions or boundaries imposed by the application, such as actions a user cannot perform or information they cannot access. Testing these restrictions helps uncover potential vulnerabilities where these boundaries can be bypassed.

What is IDOR, and why is it important to test for it in SaaS applications?

IDOR (Insecure Direct Object Reference) occurs when users can manipulate identifiers (like IDs) in the URL or parameters to access unauthorized resources. It's important to test for IDOR because it allows attackers to bypass access controls and gain unauthorized access to sensitive data.

Why does the speaker suggest mapping out an RBAC structure when testing an application?

Mapping out the RBAC structure helps identify roles and their associated permissions, making it easier to test for privilege escalation and other issues where users may have more access than they should, potentially compromising the application.

What is the significance of HTML injection in the context of invite functionality?

HTML injection occurs when user-controlled input is improperly handled, allowing the attacker to inject HTML code into emails or other parts of the application. In the case of invites, it can be used to manipulate the invite emails, often leading to social engineering attacks or other vulnerabilities.