AI-Powered Security Code Audit

The gap between SAST and real security

Static Application Security Testing (SAST) tools are a necessary part of any security programme. They detect known vulnerability patterns efficiently: SQL injection via string concatenation, cross-site scripting from unsanitised output, hardcoded credentials in source files. These are important findings, and every team should run SAST tools as part of their development workflow.

But SAST tools operate by matching code against a library of known vulnerability patterns. They excel at finding issues that can be expressed as syntactic rules. They struggle with – and often miss entirely – security issues that depend on understanding the application's business logic, data flow across multiple files, and the intent behind code rather than just its syntax.

Consider an authorisation check that verifies a user's role before allowing access to a resource. The check exists, so SAST tools see an authorisation function being called and move on. But the check compares the user's role against a hardcoded list that was last updated three role additions ago. Two new roles have implicit admin access that the check does not account for. This is an authorisation bypass, but it requires understanding the relationship between the role model, the access control logic, and the current set of roles in the system – context that pattern matching cannot provide.

VibeRails complements SAST tools by applying AI reasoning across your entire codebase. It does not replace Semgrep, Snyk, or SonarQube – it finds the category of security issues that those tools are architecturally unable to detect. The combination of SAST for pattern-based vulnerabilities and VibeRails for context-dependent security analysis provides significantly broader coverage than either approach alone.

What VibeRails finds in security audits

VibeRails analyses every file in your codebase and surfaces security issues across these categories:

• Authentication logic flaws – session management that does not invalidate tokens on password change, JWT implementations that accept the “none” algorithm, password reset flows that leak timing information, and multi-factor authentication that can be bypassed by replaying a previous valid token.
• Authorisation bypass – endpoints that check authentication but not authorisation, role checks that do not account for role hierarchy changes, object-level access control that relies on client-supplied identifiers without server-side ownership verification, and admin functions exposed through predictable URL patterns.
• Injection vulnerabilities – SQL injection via dynamic query construction in ORM escape hatches, command injection through unsanitised user input passed to shell commands, LDAP injection in directory service queries, and template injection in server-side rendering engines.
• Cryptographic misuse – use of deprecated algorithms (MD5, SHA-1 for security purposes), ECB mode encryption, predictable initialisation vectors, insufficient key lengths, and custom cryptographic implementations that should use battle-tested libraries instead.
• Secrets in code – API keys, database credentials, and tokens embedded in source files, configuration files committed to version control, and environment variable fallbacks that use hardcoded default values in production.
• SSRF and CSRF – server-side request forgery through user-controllable URLs without allowlist validation, cross-site request forgery on state-changing endpoints without token verification, and DNS rebinding vulnerabilities in URL validation logic.
• Insecure deserialisation – deserialisation of untrusted data using libraries with known gadget chains, pickle/marshal usage on user-supplied input, and JSON deserialisation into polymorphic types without type restrictions.
• Logging of sensitive data – request logging that includes authentication tokens, error handlers that expose stack traces with database connection strings, and audit logs that record full request bodies including passwords and personal data.

Context-dependent analysis that rules cannot replicate

The most dangerous security vulnerabilities are those that look correct when examined in isolation. Each individual function follows best practices. The vulnerability only emerges when you understand how multiple components interact.

For example, an application might correctly validate user input at the API boundary, sanitising special characters and enforcing length limits. But a background job processes the same data from a message queue, where it arrives in a different format that bypasses the original validation logic. The input validation is correct – it just does not cover all entry points. Finding this requires tracing data flow across the API handler, the message publisher, the queue consumer, and the background job processor.

VibeRails performs this kind of cross-file analysis automatically. It identifies all the paths through which data enters the system, tracks where validation and sanitisation occur, and flags paths where data reaches sensitive operations without adequate checks. This is the same kind of reasoning a skilled security engineer performs during a manual code audit, applied systematically across every file in the codebase.

Business logic vulnerabilities are another category that requires contextual understanding. A payment processing flow might correctly validate that the payment amount matches the invoice total. But if the invoice total can be modified through a separate API endpoint after the payment is initiated, the validation is checking stale data. SAST tools see a validation check and move on. VibeRails understands the temporal relationship between the modification endpoint and the payment flow.

Security audit pricing and workflow

Professional security code audits typically cost between ten thousand and fifty thousand dollars per engagement. They produce thorough reports, but the audit covers a snapshot of the codebase at a single point in time. By the next sprint, new code has been deployed that was not reviewed.

VibeRails provides a different model:

• Per-developer pricing – $19/month per developer or $299 lifetime per developer. Run security-focused scans as often as you need. No per-engagement cost, no retainer fees, no budget approval required for each review cycle.
• Continuous security review – scan after every major release, before every compliance audit, or whenever the security team wants a fresh assessment. Each licence covers unlimited scans.
• Free tier to evaluate – 5 issues per review at no cost. Run a security-focused scan on your codebase today and see the types of findings VibeRails produces.
• BYOK for data sovereignty – your source code is read from disk locally and sent directly to the AI provider you configured. It never passes through VibeRails servers. For security-conscious organisations, this means there is no VibeRails cloud backend ingesting your repository.
• Exportable audit reports – generate HTML reports for security team review or CSV exports for integration with vulnerability management systems. Each finding includes severity, file path, code location, and remediation guidance.

Complement your existing security toolchain

VibeRails is not a replacement for your existing security tools. It fills a specific gap in the security analysis pipeline: context-dependent vulnerability detection that requires reasoning about code semantics rather than matching syntax patterns.

Use SAST tools for known vulnerability patterns. Use dependency scanners for CVEs in third-party libraries. Use penetration testing for runtime behaviour and deployment configuration issues. Use VibeRails for the logic-level security issues that none of these tools are designed to find – the authorisation bypasses, the authentication edge cases, and the business logic vulnerabilities that require understanding what the code is supposed to do, not just what it looks like.

Download the free tier and run your first security-focused scan. If the findings are valuable, upgrade to Pro ($19/month per developer, or $299 lifetime) and make AI-powered security review a regular part of your development process.