Integer Overflow in Adonisjs with Basic Auth

An integer overflow in an AdonisJS application that also uses HTTP Basic Authentication can amplify the impact on authentication and access control. In AdonisJS, numeric values such as IDs, version counters, or size fields are often parsed from request inputs (query strings, route params, or the body). If these values originate from or are influenced by Basic Auth—either directly via the Authorization header or indirectly via user identity loaded from auth—integer overflow can corrupt calculations, bypass ownership checks, or trigger unexpected behavior in the application logic.

Consider an endpoint that accepts a numeric version parameter to perform an update. If the endpoint first authenticates the request using Basic Auth, it derives a user identity from the credentials. The user-supplied version may be combined with the authenticated user’s stored version or a database sequence. For example, JavaScript’s 32-bit integer handling (or unchecked 32-bit arithmetic in underlying bindings) can wrap around when values exceed 2^32 - 1. An attacker could supply a very large version number, causing the computed delta to wrap to a small or zero value, which can result in incorrect update eligibility or privilege escalation when ownership checks rely on that computed value.

When Basic Auth is used, the authenticated user’s attributes (such as numeric IDs, counters, or roles) are loaded server-side and may be used in arithmetic without strict validation. If the endpoint performs operations like newSequence = userSequence + clientVersion without validating that the sum remains within safe bounds, an overflow can flip a high numeric guard into a low one. This can inadvertently grant access to another user’s resource (BOLA/IDOR) or allow privilege escalation if the overflowed value is used in authorization decisions. The risk is compounded when these operations occur before strict input validation or type coercion in AdonisJS routes and controllers.

In the context of the 12 security checks run by middleBrick, integer overflow is surfaced alongside findings such as Input Validation and Property Authorization. The scanner tests whether numeric inputs derived from or influenced by authentication can be manipulated to produce invalid results. Real-world attack patterns that map to this include data tampering and access bypass, which align with OWASP API Top 10 #1 (Broken Object Level Authorization). middleBrick’s OpenAPI/Swagger analysis, including full $ref resolution, cross-references spec definitions with runtime findings to highlight parameters influenced by authentication that lack integer range constraints.

Remediation focuses on validating and sanitizing all numeric inputs before they are combined with authenticated user data, and on avoiding arithmetic on attacker-controlled values derived from Basic Auth. Ensure that parameters parsed from routes, query strings, or request bodies are constrained to safe integer ranges and are treated as unsigned where appropriate. Explicitly cast and check values before using them in calculations tied to authenticated identities.

Below are concrete AdonisJS code examples that demonstrate secure handling when Basic Auth is in use.

Example 1: Validating numeric parameters with basic auth

import { schema, rules } from '@ioc:Adonis/Core/Validator'
import { HttpContextContract } from '@ioc:Adonis/Core/HttpContext'

export default class ItemsController {
  public async updateVersion({ request, auth, response }: HttpContextContract) {
    const basicUser = auth.getUserOrFail() // user from Basic Auth
    const payload = request.validate({
      schema: schema.create({
        version: schema.number([
          rules.range(1, 4294967295), // enforce safe 32-bit unsigned range
          rules.unsigned()
        ])
      })
    })

    // Safe arithmetic: validate before using with user-derived values
    const MAX_SEQUENCE = 4294967295
    const safeVersion = Math.min(payload.version, MAX_SEQUENCE)
    const newSequence = (basicUser.sequence || 0) + safeVersion

    if (newSequence > MAX_SEQUENCE) {
      return response.badRequest({ error: 'version overflow' })
    }

    // Proceed with update using newSequence, ensuring it remains bounded
    await basicUser.related('data').merge({ sequence: newSequence })
    return response.ok({ updated: true })
  }
}

Example 2: Parameter parsing and ownership check

import { schema, rules } from '@ioc:Adonis/Core/Validator'
import { HttpContextContract } from '@ioc:Adonis/Core/HttpContext'

export default class ResourcesController {
  public async show({ params, request, auth, response }: HttpContextContract) {
    const basicUser = auth.getUserOrFail()
    const payload = request.validate({
      schema: schema.create({
        resourceId: schema.number([
          rules.range(1, 2147483647),
          rules.unsigned()
        ])
      })
    })

    // Enforce ownership using validated IDs, not computed overflow-prone values
    const resource = await Resource.findOrFail(payload.resourceId)
    if (resource.userId !== basicUser.id) {
      return response.forbidden({ error: 'access denied' })
    }

    return response.ok(resource)
  }
}

These examples emphasize strict unsigned range checks and avoiding arithmetic that combines authenticated state with untrusted input. When integrating with middleBrick’s scans, pay attention to findings under Input Validation and Property Authorization; they often flag parameters influenced by authentication that lack proper integer constraints. middleBrick’s OpenAPI/Swagger analysis, with full $ref resolution, can highlight endpoints where Basic Auth-derived user data flows into numeric operations without sufficient validation.