Web App API Attacks

An incident responder investigates a RESTful API where users can access sensitive records simply by incrementing an integer ID in the endpoint URL, such as changing /api/v1/users/104/profile to /api/v1/users/105/profile without providing additional authorization checks. Which vulnerability class does this scenario represent?

During a web application incident investigation, the SOC analyst discovers that an attacker sent a modified JSON payload containing an unexpected administrative attribute "is_admin": true during user registration, which successfully elevated the user's privileges. What vulnerability enabled this exploitation?

An attacker discovers an API endpoint /api/v1/user/details?id=123 that returns JSON data. They modify the parameter to /api/v1/user/details?id=124. This vulnerability indicates a failure in which security control?

Which TWO methods are effective for mitigating Mass Assignment vulnerabilities in RESTful APIs?

An API uses OAuth 2.0. An attacker sends a request with a modified 'redirect_uri' parameter to an authorization endpoint. If successful, this could lead to which type of vulnerability?

Which THREE items are essential components of an API security documentation strategy for incident responders?

When analyzing a JSON Web Token (JWT) for potential security weaknesses in an API, which scenario indicates a 'None' algorithm attack is possible?

Which security measure is most effective against API-based Denial of Service (DoS) attacks targeted at resource-intensive endpoints?

Refer to the exhibit. An attacker changes the 'final_price' to 0.00. What is the most likely vulnerability?

Which of the following is the most significant security risk associated with the use of 'API Keys' for authentication in modern cloud-native environments?

In the context of API security, what does the 'Broken Object Level Authorization' (BOLA) vulnerability typically involve?

Which THREE actions are recommended to secure APIs against Server-Side Request Forgery (SSRF)?

An incident responder is analyzing an API access log and notices a user with ID 104 is able to modify account settings for user ID 105 by simply changing the integer value in the URI endpoint from /api/v1/users/104/settings to /api/v1/users/105/settings without any additional token validation or role checks. Which specific OWASP API Security Top 10 vulnerability class does this scenario represent?

An incident responder is investigating a modern web application and notices that users can modify object identifiers in REST API endpoints to access sensitive records belonging to other tenants. Which primary vulnerability category does this represent?

An incident responder is investigating a RESTful API breach where an authenticated low-privileged user accessed administrative records by modifying an integer identifier in the resource path from /api/v1/users/104 to /api/v1/users/1. Which type of vulnerability has been exploited?

During a penetration test of a GraphQL API, an incident handler finds that the introspection system is enabled and can be queried without authentication. The handler retrieves the full schema, including hidden fields and mutations. What is the most significant security impact of this finding?

An incident responder is analyzing a web application that uses a REST API. The API accepts a 'file' parameter that specifies a URL from which to fetch an image. The responder observes that an attacker supplied a URL pointing to an internal metadata service (e.g., http://169.254.169.254/latest/meta-data/) and successfully retrieved sensitive instance credentials. Which vulnerability class does this represent?

A GCIH incident handler is reviewing web server logs after a suspected API reconnaissance campaign. The logs show numerous requests to endpoints such as /api/v1/users, /api/v2/users, /api/v3/users, and /api/internal/users, all returning HTTP 404 except one. Which attack technique is most consistent with this pattern?

A security analyst is reviewing logs from a web application firewall (WAF) and notices a series of requests containing payloads like ' OR 1=1 --' and 'UNION SELECT username, password FROM users'. These requests are targeting the login endpoint. Which type of attack is being attempted?

During an incident response engagement, a GCIH analyst examines an API that accepts JSON input and notices that the application returns detailed database error messages when a single quote is inserted into the 'username' field. The analyst also observes that the same endpoint returns a 500 error when a specially crafted JSON object with nested arrays is submitted. Which vulnerability class is the analyst most likely investigating?

An incident handler reviews web server logs from an e-commerce application and finds a burst of requests where the JSON body of a POST to /api/v2/orders/checkout contains a deeply nested object several thousand levels deep, causing the backend deserializer to exhaust CPU and memory until the worker crashes. The application accepts arbitrary JSON and binds it directly to internal model objects. Which vulnerability class best describes this attack?

A GCIH incident responder is investigating a suspected API attack where an attacker manipulated a JSON Web Token (JWT) to gain unauthorized access. The responder needs to identify which two conditions would allow a JWT 'kid' (Key ID) header injection attack to succeed. (Choose two.)

A GCIH analyst is called after a SaaS provider reports that an integration partner's API traffic began returning other tenants' records. The partner's client was calling /api/v3/documents/{documentId} and had recently started sending a second header, X-Tenant-Id, that the gateway trusts to route requests. The analyst confirms the partner is authenticated with a valid OAuth 2.0 bearer token scoped to its own tenant. Which weakness allowed the cross-tenant exposure?

A GCIH analyst is examining a web application that uses GraphQL. The analyst notices that an attacker sent a deeply nested query that caused the server to consume excessive resources, leading to a denial of service. Which GraphQL-specific vulnerability is being exploited?

A GCIH candidate is reviewing a REST API that accepts XML in an upload endpoint used for importing supplier catalogs. During a purple-team exercise, testers want to demonstrate how XML-specific parser weaknesses could be abused against this endpoint. Which two techniques should the testers attempt to validate the parser's defenses? (Choose two.)

A SOC analyst triages an alert showing that a mobile banking API responded to a request for /api/accounts/8842/transactions with HTTP 200 and another customer's transaction list. The requesting user was authenticated normally with a valid session token, but the account number in the URL belonged to a different customer. The API returned data without checking whether the authenticated user owned that account. Which vulnerability does this represent?

An incident responder is examining a GraphQL API after a breach report. Query logs show a single POST to /graphql containing a query that requests a user's profile, that user's friends, each friend's friends, and so on through deeply chained relationship fields, all in one request. The response was several megabytes and the database showed a spike in joins. No authentication bypass occurred. Which attack does this describe?

During an incident involving a single-page application, a handler inspects a GraphQL endpoint at /graphql used for a customer portal. The handler captures a query that requests only the fields needed for a profile view, but the server response includes additional fields such as internalAccountTier, billingNotes, and ssnLastFour. The application uses a single shared GraphQL schema and no field-level authorization middleware. Which GraphQL-specific weakness is most directly demonstrated?