GHSA-6q22-g298-grjh
Directus: Unauthenticated Denial of Service via GraphQL Alias Amplification of Expensive Health Check Resolver
High
npm
Description
Summary
The GraphQL specification permits a single query to repeat the same field multiple times using aliases, with each alias resolved independently by default. Directus did not deduplicate resolver invocations within a single request, meaning each alias triggered a full, independent execution of the underlying resolver.
The health check resolver ran all backend checks (database connectivity, cache, storage writes, and SMTP verification) on every invocation. Combined with unauthenticated access to the system GraphQL endpoint, this allowed an attacker to amplify resource consumption significantly from a single HTTP request, exhausting the database connection pool, storage I/O, and SMTP connections.
Fix
A request-scoped resolver deduplication mechanism was introduced and applied broadly across all GraphQL read resolvers, both system and items endpoints. When multiple aliases in a single request invoke the same resolver with identical arguments, only the first call executes; all subsequent aliases share its result. This eliminates the amplification factor regardless of how many aliases an attacker includes in a query.
Impact
- Service degradation or outage: Database connection pool exhaustion prevents all Directus operations for all users
- Storage I/O saturation: Concurrent file writes can overwhelm disk I/O
- SMTP resource exhaustion: Concurrent SMTP verification calls may overwhelm the mail server
- No authentication required: Any network-accessible attacker can trigger this condition
- Single-request impact: A single request is sufficient to cause significant resource consumption
Credit
This vulnerability was discovered and reported by bugbunny.ai.
Affected versions
npm
| Package | Vulnerable | Fixed in |
|---|---|---|
| directus | < 11.17.0 |
11.17.0 |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
directus npm → 11.17.0
- npm
npm install directus@11.17.0- yarn
yarn add directus@11.17.0- pnpm
pnpm add directus@11.17.0
Severity breakdown
CVSS 3.1 7.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Weakness
CWE-400: Uncontrolled Resource Consumption
The product does not properly control the allocation and maintenance of a limited resource.
How to prevent it
- Architecture and Design: Design throttling mechanisms into the system architecture. The best protection is to limit the amount of resources that an unauthorized user can cause to be expended. A strong authentication and access control model will help prevent such attacks from occurring in the first place. The login application should be protected against DoS attacks as much as possible. Limiting the database access, perhaps by caching result sets, can help minimize the resources expended. To further limit the potential for a DoS attack, consider tracking the rate of requests received from users and blocking requests that exceed a defined rate threshold.
- Architecture and Design: Mitigation of resource exhaustion attacks requires that the target system either: recognizes the attack and denies that user further access for a given amount of time, or uniformly throttles all requests in order to make it more difficult to consume resources more quickly than they can again be freed. The first of these solutions is an issue in itself though, since it may allow attackers to prevent the use of the system by a particular valid user. If the attacker impersonates the valid user, they may be able to prevent the user from accessing the server in question. The second solution is simply difficult to effectively institute -- and even when properly done, it does not provide a full solution. It simply makes the attack require more resources on the part of the attacker.
- Architecture and Design: Ensure that protocols have specific limits of scale placed on them.
- Implementation: Ensure that all failures in resource allocation place the system into a safe posture.
CWE-770: Allocation of Resources Without Limits or Throttling
The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.
How to prevent it
- Requirements: Clearly specify the minimum and maximum expectations for capabilities, and dictate which behaviors are acceptable when resource allocation reaches limits.
- Architecture and Design: Limit the amount of resources that are accessible to unprivileged users. Set per-user limits for resources. Allow the system administrator to define these limits. Be careful to avoid CWE-410.
- Architecture and Design: Design throttling mechanisms into the system architecture. The best protection is to limit the amount of resources that an unauthorized user can cause to be expended. A strong authentication and access control model will help prevent such attacks from occurring in the first place, and it will help the administrator to identify who is committing the abuse. The login application should be protected against DoS attacks as much as possible. Limiting the database access, perhaps by caching result sets, can help minimize the resources expended. To further limit the potential for a DoS attack, consider tracking the rate of requests received from users and blocking requests that exceed a defined rate threshold.
- Implementation: Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does. When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue." Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
- Architecture and Design: For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.
- Architecture and Design: Mitigation of resource exhaustion attacks requires that the target system either: recognizes the attack and denies that user further access for a given amount of time, typically by using increasing time delays uniformly throttles all requests in order to make it more difficult to consume resources more quickly than they can again be freed. The first of these solutions is an issue in itself though, since it may allow attackers to prevent the use of the system by a particular valid user. If the attacker impersonates the valid user, they may be able to prevent the user from accessing the server in question. The second solution can be difficult to effectively institute -- and even when properly done, it does not provide a full solution. It simply requires more resources on the part of the attacker.
- Architecture and Design: Ensure that protocols have specific limits of scale placed on them.
- Architecture and Design, Implementation: If the program must fail, ensure that it fails gracefully (fails closed). There may be a temptation to simply let the program fail poorly in cases such as low memory conditions, but an attacker may be able to assert control before the software has fully exited. Alternately, an uncontrolled failure could cause cascading problems with other downstream components; for example, the program could send a signal to a downstream process so the process immediately knows that a problem has occurred and has a better chance of recovery. Ensure that all failures in resource allocation place the system into a safe posture.
- Operation, Architecture and Design: Use quotas or other resource-limiting settings provided by the operating system or environment. For example, when managing system resources in POSIX, setrlimit() can be used to set limits for certain types of resources, and getrlimit() can determine how many resources are available. However, these functions are not available on all operating systems. When the current levels get close to the maximum that is defined for the application (see CWE-770), then limit the allocation of further resources to privileged users; alternately, begin releasing resources for less-privileged users. While this mitigation may protect the system from attack, it will not necessarily stop attackers from adversely impacting other users. Ensure that the application performs the appropriate error checks and error handling in case resources become unavailable (CWE-703).
References
Packages
Other links
Timeline
- Published
- Last updated by the source
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-c6w9-5g5j-jh2p Directus: Authorization-dependent response served from unsegmented cache key | High | Also affects directus |
| GHSA-j5h6-vqc3-phqh Directus: SSRF Protection Bypass via 0.0.0.0 in File Import | High | Also affects directus |
| GHSA-38hg-ww64-rrwc Directus: Authenticated Users Can Extract Concealed Fields via Aggregate Queries | High | Also affects directus |
| GHSA-ph52-67fq-75wj Directus: GraphQL Alias Amplification Denial of Service Due to Missing Query Cost/Complexity Limits | Medium | Also affects directus |
| GHSA-mvv8-v4jj-g47j Directus: Sensitive fields exposed in revision history | Medium | Also affects directus |
| GHSA-qqmv-5p3g-px89 Directus: TUS Upload Authorization Bypass Allows Arbitrary File Overwrite | High | Also affects directus |
| GHSA-wv3h-5fx7-966h Directus: SSRF Protection Bypass via IPv4-Mapped IPv6 Addresses in File Import | High | Also affects directus |
| GHSA-wxwm-3fxv-mrvx Directus: GraphQL Schema SDL Disclosure Setting | Medium | Also affects directus |
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