Uncontrolled Resource Consumption

Draft Class

Structure: Simple

Description

The product does not properly control the allocation and maintenance of a limited resource.

Common Consequences 2

Scope: Availability

Impact: DoS: Crash, Exit, or RestartDoS: Resource Consumption (CPU)DoS: Resource Consumption (Memory)DoS: Resource Consumption (Other)

If an attacker can trigger the allocation of the limited resources, but the number or size of the resources is not controlled, then the most common result is denial of service. This would prevent valid users from accessing the product, and it could potentially have an impact on the surrounding environment, i.e., the product may slow down, crash due to unhandled errors, or lock out legitimate users. For example, a memory exhaustion attack against an application could slow down the application as well as its host operating system.

Scope: Access ControlOther

Impact: Bypass Protection MechanismOther

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 3

Automated Static AnalysisLimited

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.

Automated Dynamic AnalysisModerate

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.

FuzzingOpportunistic

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.

Potential Mitigations 4

Phase: 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.

Phase: 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.

Phase: Architecture and Design

Ensure that protocols have specific limits of scale placed on them.

Phase: Implementation

Ensure that all failures in resource allocation place the system into a safe posture.

Demonstrative Examples 6

The following example demonstrates the weakness.

Code Example:

Bad

Java

java

// postpone response* Thread.currentThread().interrupt();}}

java

There are no limits to runnables. Potentially an attacker could cause resource problems very quickly.

ID : DX-25

This code allocates a socket and forks each time it receives a new connection.

Code Example:Bad
C
c

The program does not track how many connections have been made, and it does not limit the number of connections. Because forking is a relatively expensive operation, an attacker would be able to cause the system to run out of CPU, processes, or memory by making a large number of connections. Alternatively, an attacker could consume all available connections, preventing others from accessing the system remotely.

ID : DX-50

In the following example a server socket connection is used to accept a request to store data on the local file system using a specified filename. The method openSocketConnection establishes a server socket to accept requests from a client. When a client establishes a connection to this service the getNextMessage method is first used to retrieve from the socket the name of the file to store the data, the openFileToWrite method will validate the filename and open a file to write to on the local file system. The getNextMessage is then used within a while loop to continuously read data from the socket and output the data to the file until there is no longer any data from the socket.

Code Example:Bad
C
c

This example creates a situation where data can be dumped to a file on the local file system without any limits on the size of the file. This could potentially exhaust file or disk resources and/or limit other clients' ability to access the service.

ID : DX-51

In the following example, the processMessage method receives a two dimensional character array containing the message to be processed. The two-dimensional character array contains the length of the message in the first character array and the message body in the second character array. The getMessageLength method retrieves the integer value of the length from the first character array. After validating that the message length is greater than zero, the body character array pointer points to the start of the second character array of the two-dimensional character array and memory is allocated for the new body character array.

Code Example:

Bad

/* process message accepts a two-dimensional character array of the form [length][body] containing the message to be processed / int processMessage(char **message) { ``` char *body; int length = getMessageLength(message[0]); if (length > 0) { body = &message[1][0]; processMessageBody(body); return(SUCCESS); } else { printf("Unable to process message; invalid message length"); return(FAIL); } }

This example creates a situation where the length of the body character array can be very large and will consume excessive memory, exhausting system resources. This can be avoided by restricting the length of the second character array with a maximum length check

Also, consider changing the type from 'int' to 'unsigned int', so that you are always guaranteed that the number is positive. This might not be possible if the protocol specifically requires allowing negative values, or if you cannot control the return value from getMessageLength(), but it could simplify the check to ensure the input is positive, and eliminate other errors such as signed-to-unsigned conversion errors (Signed to Unsigned Conversion Error) that may occur elsewhere in the code.

Code Example:Good
C
c

ID : DX-52

In the following example, a server object creates a server socket and accepts client connections to the socket. For every client connection to the socket a separate thread object is generated using the ClientSocketThread class that handles request made by the client through the socket.

Code Example:Bad
Java
java

In this example there is no limit to the number of client connections and client threads that are created. Allowing an unlimited number of client connections and threads could potentially overwhelm the system and system resources.

The server should limit the number of client connections and the client threads that are created. This can be easily done by creating a thread pool object that limits the number of threads that are generated.

Code Example:Good
Java
java

In the following example, the serve function receives an http request and an http response writer. It reads the entire request body.

Code Example:Bad
Go
go

Because ReadAll is defined to read from src until EOF, it does not treat an EOF from Read as an error to be reported. This example creates a situation where the length of the body supplied can be very large and will consume excessive memory, exhausting system resources. This can be avoided by ensuring the body does not exceed a predetermined length of bytes.

MaxBytesReader prevents clients from accidentally or maliciously sending a large request and wasting server resources. If possible, the code could be changed to tell ResponseWriter to close the connection after the limit has been reached.

Code Example:Good
Go
go

Observed Examples 17

CVE-2019-19911Chain: Python library does not limit the resources used to process images that specify a very large number of bands (Improper Validation of Specified Quantity in Input), leading to excessive memory consumption (Memory Allocation with Excessive Size Value) or an integer overflow (Integer Overflow or Wraparound).

CVE-2020-7218Go-based workload orchestrator does not limit resource usage with unauthenticated connections, allowing a DoS by flooding the service

CVE-2020-3566Resource exhaustion in distributed OS because of "insufficient" IGMP queue management, as exploited in the wild per CISA KEV.

CVE-2009-2874Product allows attackers to cause a crash via a large number of connections.

CVE-2009-1928Malformed request triggers uncontrolled recursion, leading to stack exhaustion.

CVE-2009-2858Chain: memory leak (Improper Resource Shutdown or Release) leads to resource exhaustion.

CVE-2009-2726Driver does not use a maximum width when invoking sscanf style functions, causing stack consumption.

CVE-2009-2540Large integer value for a length property in an object causes a large amount of memory allocation.

CVE-2009-2299Web application firewall consumes excessive memory when an HTTP request contains a large Content-Length value but no POST data.

CVE-2009-2054Product allows exhaustion of file descriptors when processing a large number of TCP packets.

CVE-2008-5180Communication product allows memory consumption with a large number of SIP requests, which cause many sessions to be created.

CVE-2008-2121TCP implementation allows attackers to consume CPU and prevent new connections using a TCP SYN flood attack.

CVE-2008-2122Port scan triggers CPU consumption with processes that attempt to read data from closed sockets.

CVE-2008-1700Product allows attackers to cause a denial of service via a large number of directives, each of which opens a separate window.

CVE-2007-4103Product allows resource exhaustion via a large number of calls that do not complete a 3-way handshake.

CVE-2006-1173Mail server does not properly handle deeply nested multipart MIME messages, leading to stack exhaustion.

CVE-2007-0897Chain: anti-virus product encounters a malformed file but returns from a function without closing a file descriptor (Missing Release of File Descriptor or Handle after Effective Lifetime) leading to file descriptor consumption (Uncontrolled Resource Consumption) and failed scans.

References 5

The CLASP Application Security Process

Secure Software, Inc.

2005

https://cwe.mitre.org/documents/sources/TheCLASPApplicationSecurityProcess.pdf(2024-11-17)

ID: REF-18

Detection and Prediction of Resource-Exhaustion Vulnerabilities

Joao Antunes, Nuno Ferreira Neves, and Paulo Verissimo

Proceedings of the IEEE International Symposium on Software Reliability Engineering (ISSRE)

11-2008

https://www.di.fc.ul.pt/~nuno/PAPERS/ISSRE08.pdf(2025-07-24)

ID: REF-386

Resource exhaustion

D.J. Bernstein

http://cr.yp.to/docs/resources.html

ID: REF-387

Resource exhaustion

Pascal Meunier

Secure Programming Educational Material

2004

http://homes.cerias.purdue.edu/~pmeunier/secprog/sanitized/class1/6.resource%20exhaustion.ppt

ID: REF-388

Writing Secure Code

Michael Howard and David LeBlanc

Microsoft Press

04-12-2002

https://www.microsoftpressstore.com/store/writing-secure-code-9780735617223

ID: REF-7

Likelihood of Exploit

High

Applicable Platforms

Languages:

Not Language-Specific : Undetermined

Modes of Introduction

Operation

System Configuration

Architecture and Design

Implementation

Related Attack Patterns

Alternate Terms

Resource Exhaustion

Related Weaknesses

ChildOf:

Improper Control of a Resource Through its Lifetime (CWE-664)

Taxonomy Mapping

CLASP
OWASP Top Ten 2004
WASC
WASC
The CERT Oracle Secure Coding Standard for Java (2011)
The CERT Oracle Secure Coding Standard for Java (2011)
Software Fault Patterns
ISA/IEC 62443
ISA/IEC 62443
ISA/IEC 62443
ISA/IEC 62443
ISA/IEC 62443
ISA/IEC 62443

Notes

Maintenance"Resource consumption" could be interpreted as a consequence instead of an insecure behavior, so this entry is being considered for modification. It appears to be referenced too frequently when more precise mappings are available. Some of its children, such as Missing Reference to Active Allocated Resource, might be better considered as a chain.

TheoreticalVulnerability theory is largely about how behaviors and resources interact. "Resource exhaustion" can be regarded as either a consequence or an attack, depending on the perspective. This entry is an attempt to reflect the underlying weaknesses that enable these attacks (or consequences) to take place.

Other Database queries that take a long time to process are good DoS targets. An attacker would have to write a few lines of Perl code to generate enough traffic to exceed the site's ability to keep up. This would effectively prevent authorized users from using the site at all. Resources can be exploited simply by ensuring that the target machine must do much more work and consume more resources in order to service a request than the attacker must do to initiate a request. A prime example of this can be found in old switches that were vulnerable to "macof" attacks (so named for a tool developed by Dugsong). These attacks flooded a switch with random IP and MAC address combinations, therefore exhausting the switch's cache, which held the information of which port corresponded to which MAC addresses. Once this cache was exhausted, the switch would fail in an insecure way and would begin to act simply as a hub, broadcasting all traffic on all ports and allowing for basic sniffing attacks. Limited resources include memory, file system storage, database connection pool entries, CPU, and others.

MaintenanceThe Taxonomy_Mappings to ISA/IEC 62443 were added in CWE 4.10, but they are still under review and might change in future CWE versions. These draft mappings were performed by members of the "Mapping CWE to 62443" subgroup of the CWE-CAPEC ICS/OT Special Interest Group (SIG), and their work is incomplete as of CWE 4.10. The mappings are included to facilitate discussion and review by the broader ICS/OT community, and they are likely to change in future CWE versions.