CWE-400: Uncontrolled Resource Consumption
| Abstraction | Structure | Status |
|---|---|---|
| None | Simple | Draft |
Description
The product does not properly control the allocation and maintenance of a limited resource, thereby enabling an actor to influence the amount of resources consumed, eventually leading to the exhaustion of available resources.
Extended Description
Limited resources include memory, file system storage, database connection pool entries, and CPU. If an attacker can trigger the allocation of these limited resources, but the number or size of the resources is not controlled, then the attacker could cause a denial of service that consumes all available resources. This would prevent valid users from accessing the product, and it could potentially have an impact on the surrounding environment. For example, a memory exhaustion attack against an application could slow down the application as well as its host operating system.
There are at least three distinct scenarios which can commonly lead to resource exhaustion:
- Lack of throttling for the number of allocated resources
- Losing all references to a resource before reaching the shutdown stage
- Not closing/returning a resource after processing
Resource exhaustion problems are often result due to an incorrect implementation of the following situations:
- Error conditions and other exceptional circumstances.
- Confusion over which part of the program is responsible for releasing the resource.
Alternate Terms
- Resource Exhaustion:
Related Weaknesses
| Nature | ID | View ID | Name |
|---|---|---|---|
| ChildOf | CWE-664 | 1000 | Improper Control of a Resource Through its Lifetime |
Modes of Introduction
| Phase | Note |
|---|---|
| Operation | - |
| Architecture and Design | - |
| Implementation | - |
Applicable Platforms
Languages
Class: Not Language-Specific
Technologies
Likelihood Of Exploit
High
Common Consequences
| Scope | Impact | Note |
|---|---|---|
| Availability | DoS: Crash, Exit, or Restart, DoS: Resource Consumption (CPU), DoS: Resource Consumption (Memory), DoS: Resource Consumption (Other) | The most common result of resource exhaustion is denial of service. The product may slow down, crash due to unhandled errors, or lock out legitimate users. |
| Access Control, Other | Bypass Protection Mechanism, Other | In some cases it may be possible to force the product to “fail open” in the event of resource exhaustion. The state of the product – and possibly the security functionality - may then be compromised. |
Detection Methods
Automated Static Analysis
Automated static analysis typically has limited utility in recognizing resource exhaustion problems, except for program-independent system resources such as files, sockets, and processes. For system resources, automated static analysis may be able to detect circumstances in which resources are not released after they have expired. Automated analysis of configuration files may be able to detect settings that do not specify a maximum value.
Automated static analysis tools will not be appropriate for detecting exhaustion of custom resources, such as an intended security policy in which a bulletin board user is only allowed to make a limited number of posts per day.
Effectiveness: Limited
Automated Dynamic Analysis
Certain automated dynamic analysis techniques may be effective in spotting resource exhaustion problems, especially with resources such as processes, memory, and connections. The technique may involve generating a large number of requests to the product within a short time frame.
Effectiveness: Moderate
Fuzzing
While fuzzing is typically geared toward finding low-level implementation bugs, it can inadvertently find resource exhaustion problems. This can occur when the fuzzer generates a large number of test cases but does not restart the targeted product in between test cases. If an individual test case produces a crash, but it does not do so reliably, then an inability to handle resource exhaustion may be the cause.
Effectiveness: Opportunistic
Potential Mitigations
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.
Observed Examples
- CVE-2022-21668: Chain: Python library does not limit the resources used to process images that specify a very large number of bands (CWE-1284), leading to excessive memory consumption (CWE-789) or an integer overflow (CWE-190).
- CVE-2020-7218: Go-based workload orchestrator does not limit resource usage with unauthenticated connections, allowing a DoS by flooding the service
- CVE-2020-3566: Resource exhaustion in distributed OS because of “insufficient” IGMP queue management, as exploited in the wild per CISA KEV.
- CVE-2009-2874: Product allows attackers to cause a crash via a large number of connections.
- CVE-2009-1928: Malformed request triggers uncontrolled recursion, leading to stack exhaustion.
- CVE-2009-2858: Chain: memory leak (CWE-404) leads to resource exhaustion.
- CVE-2009-2726: Driver does not use a maximum width when invoking sscanf style functions, causing stack consumption.
- CVE-2009-2540: Large integer value for a length property in an object causes a large amount of memory allocation.
- CVE-2009-2299: Web application firewall consumes excessive memory when an HTTP request contains a large Content-Length value but no POST data.
- CVE-2009-2054: Product allows exhaustion of file descriptors when processing a large number of TCP packets.
- CVE-2008-5180: Communication product allows memory consumption with a large number of SIP requests, which cause many sessions to be created.
- CVE-2008-2121: TCP implementation allows attackers to consume CPU and prevent new connections using a TCP SYN flood attack.
- CVE-2008-2122: Port scan triggers CPU consumption with processes that attempt to read data from closed sockets.
- CVE-2008-1700: Product allows attackers to cause a denial of service via a large number of directives, each of which opens a separate window.
- CVE-2007-4103: Product allows resource exhaustion via a large number of calls that do not complete a 3-way handshake.
- CVE-2006-1173: Mail server does not properly handle deeply nested multipart MIME messages, leading to stack exhaustion.
- CVE-2007-0897: Chain: anti-virus product encounters a malformed file but returns from a function without closing a file descriptor (CWE-775) leading to file descriptor consumption (CWE-400) and failed scans.