CAPEC - CAPEC-26: Leveraging Race Conditions (Version 3.9)


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CAPEC-26: Leveraging Race Conditions

Attack Pattern ID: 26

Abstraction: Meta

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Description

The adversary targets a race condition occurring when multiple processes access and manipulate the same resource concurrently, and the outcome of the execution depends on the particular order in which the access takes place. The adversary can leverage a race condition by "running the race", modifying the resource and modifying the normal execution flow. For instance, a race condition can occur while accessing a file: the adversary can trick the system by replacing the original file with their version and cause the system to read the malicious file.

Likelihood Of Attack

High

Typical Severity

High

Relationships

This table shows the other attack patterns and high level categories that are related to this attack pattern. These relationships are defined as ChildOf and ParentOf, and give insight to similar items that may exist at higher and lower levels of abstraction. In addition, relationships such as CanFollow, PeerOf, and CanAlsoBe are defined to show similar attack patterns that the user may want to explore.

Nature	Type	ID	Name
ParentOf	Standard Attack Pattern - A standard level attack pattern in CAPEC is focused on a specific methodology or technique used in an attack. It is often seen as a singular piece of a fully executed attack. A standard attack pattern is meant to provide sufficient details to understand the specific technique and how it attempts to accomplish a desired goal. A standard level attack pattern is a specific type of a more abstract meta level attack pattern.	29	Leveraging Time-of-Check and Time-of-Use (TOCTOU) Race Conditions

This table shows the views that this attack pattern belongs to and top level categories within that view.

View Name	Top Level Categories
Domains of Attack	Software, Hardware
Mechanisms of Attack	Manipulate Timing and State

Execution Flow

Explore

The adversary explores to gauge what level of access they have.

Experiment

The adversary gains access to a resource on the target host. The adversary modifies the targeted resource. The resource's value is used to determine the next normal execution action.

Exploit

The resource is modified/checked concurrently by multiple processes. By using one of the processes, the adversary is able to modify the value just before it is consumed by a different process. A race condition occurs and is exploited by the adversary to abuse the target host.

Prerequisites

A resource is accessed/modified concurrently by multiple processes such that a race condition exists.

The adversary has the ability to modify the resource.

Skills Required

[Level: Medium]

Being able to "run the race" requires basic knowledge of concurrent processing including synchonization techniques.

Consequences

This table specifies different individual consequences associated with the attack pattern. The Scope identifies the security property that is violated, while the Impact describes the negative technical impact that arises if an adversary succeeds in their attack. The Likelihood provides information about how likely the specific consequence is expected to be seen relative to the other consequences in the list. For example, there may be high likelihood that a pattern will be used to achieve a certain impact, but a low likelihood that it will be exploited to achieve a different impact.

Scope	Impact	Likelihood
Confidentiality Access Control Authorization	Gain Privileges
Integrity	Modify Data

Mitigations

Use safe libraries to access resources such as files.

Be aware that improper use of access function calls such as chown(), tempfile(), chmod(), etc. can cause a race condition.

Use synchronization to control the flow of execution.

Use static analysis tools to find race conditions.

Pay attention to concurrency problems related to the access of resources.

Example Instances

The Net Direct client for Linux before 6.0.5 in Nortel Application Switch 2424, VPN 3050 and 3070, and SSL VPN Module 1000 extracts and executes files with insecure permissions, which allows local users to exploit a race condition to replace a world-writable file in /tmp/NetClient and cause another user to execute arbitrary code when attempting to execute this client, as demonstrated by replacing /tmp/NetClient/client. See also: CVE-2007-1057

The following code illustrates a file that is accessed multiple times by name in a publicly accessible directory. A race condition exists between the accesses where an attacker can replace the file referenced by the name (see [REF-107]).

include <sys/types.h>
include <fcntl.h>
include <unistd.h>

define FILE "/tmp/myfile"
define UID 100

void test(char *str)
{

int fd;
fd = creat(FILE, 0644);
if(fd == -1)

return;

chown(FILE, UID, -1); /* BAD */
close(fd);

}

int main(int argc, char **argv)
{

char *userstr;
if(argc > 1) {

userstr = argv[1];
test(userstr);

}
return 0;

}

Related Weaknesses

A Related Weakness relationship associates a weakness with this attack pattern. Each association implies a weakness that must exist for a given attack to be successful. If multiple weaknesses are associated with the attack pattern, then any of the weaknesses (but not necessarily all) may be present for the attack to be successful. Each related weakness is identified by a CWE identifier.

CWE-ID	Weakness Name
368	Context Switching Race Condition
363	Race Condition Enabling Link Following
366	Race Condition within a Thread
370	Missing Check for Certificate Revocation after Initial Check
362	Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
662	Improper Synchronization
689	Permission Race Condition During Resource Copy
667	Improper Locking
665	Improper Initialization
1223	Race Condition for Write-Once Attributes
1254	Incorrect Comparison Logic Granularity
1298	Hardware Logic Contains Race Conditions

References

[REF-1] G. Hoglund and G. McGraw. "Exploiting Software: How to Break Code". Addison-Wesley. 2004-02.

[REF-105] "Wikipedia". Race condition. The Wikimedia Foundation, Inc. <http://en.wikipedia.org/wiki/Race_condition>.

[REF-106] David Wheeler. "Secure programmer: Prevent race conditions". IBM developerWorks. IBM. <http://www.ibm.com/developerworks/linux/library/l-sprace/index.html>.

[REF-107] Fortify Software. "SAMATE - Software Assurance Metrics And Tool Evaluation". Test Case ID 1598. National Institute of Standards and Technology (NIST). 2006-06-22. <http://samate.nist.gov/SRD/view_testcase.php?tID=1598>.

Content History

Submissions
Submission Date	Submitter	Organization
2014-06-23 (Version 2.6)	CAPEC Content Team	The MITRE Corporation

Modifications
Modification Date	Modifier	Organization
2017-01-09 (Version 2.9)	CAPEC Content Team	The MITRE Corporation
Updated Related_Attack_Patterns, Type (Relationship -> Attack_Pattern)
2017-05-01 (Version 2.10)	CAPEC Content Team	The MITRE Corporation
Updated Activation_Zone, Attack_Phases, Attack_Prerequisites, Description Summary, Injection_Vector, Payload, Payload_Activation_Impact
2018-07-31 (Version 2.12)	CAPEC Content Team	The MITRE Corporation
Updated Attacker_Skills_or_Knowledge_Required, Examples-Instances, References, Solutions_and_Mitigations
2020-07-30 (Version 3.3)	CAPEC Content Team	The MITRE Corporation
Updated Description, Example_Instances, Execution_Flow, Related_Weaknesses
2021-06-24 (Version 3.5)	CAPEC Content Team	The MITRE Corporation
Updated Related_Weaknesses
2022-09-29 (Version 3.8)	CAPEC Content Team	The MITRE Corporation
Updated Example_Instances

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Page Last Updated or Reviewed: July 31, 2018


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Common Attack Pattern Enumeration and Classification

CAPEC-26: Leveraging Race Conditions