Home > CAPEC List > CAPEC-92: Forced Integer Overflow (Version 3.0)  

CAPEC-92: Forced Integer Overflow

Attack Pattern ID: 92
Abstraction: Detailed
Status: Draft
Presentation Filter:
+ Description
This attack forces an integer variable to go out of range. The integer variable is often used as an offset such as size of memory allocation or similarly. The attacker would typically control the value of such variable and try to get it out of range. For instance the integer in question is incremented past the maximum possible value, it may wrap to become a very small, or negative number, therefore providing a very incorrect value which can lead to unexpected behavior. At worst the attacker can execute arbitrary code.
+ Likelihood Of Attack

High

+ Typical Severity

High

+ Relationships

The table(s) below shows the other attack patterns and high level categories that are related to this attack pattern. These relationships are defined as ChildOf, ParentOf, MemberOf 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.

+ Relevant to the view "Mechanisms of Attack" (CAPEC-1000)
NatureTypeIDName
ChildOfStandard Attack PatternStandard 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.128Integer Attacks
+ Execution Flow
Explore
  1. The first step is exploratory meaning the attacker looks for an integer variable that he can control.

Experiment
  1. The attacker finds an integer variable that he can write into or manipulate and try to get the value of the integer out of the possible range.

Exploit
  1. The integer variable is forced to have a value out of range which set its final value to an unexpected value.

  2. The target host acts on the data and unexpected behavior may happen.

+ Prerequisites
The attacker can manipulate the value of an integer variable utilized by the target host.
The target host does not do proper range checking on the variable before utilizing it.
When the integer variable is incremented or decremented to an out of range value, it gets a very different value (e.g. very small or negative number)
+ Skills Required
[Level: Low]
An attacker can simply overflow an integer by inserting an out of range value.
[Level: High]
Exploiting a buffer overflow by injecting malicious code into the stack of a software system or even the heap can require a higher skill level.
+ Consequences

The table below 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.

ScopeImpactLikelihood
Integrity
Modify Data
Confidentiality
Access Control
Authorization
Gain Privileges
Confidentiality
Integrity
Availability
Execute Unauthorized Commands
Confidentiality
Read Data
Availability
Unreliable Execution
+ Mitigations
Use a language or compiler that performs automatic bounds checking.
Carefully review the service's implementation before making it available to user. For instance you can use manual or automated code review to uncover vulnerabilities such as integer overflow.
Use an abstraction library to abstract away risky APIs. Not a complete solution.
Always do bound checking before consuming user input data.
+ Example Instances
Integer overflow in the ProcAuWriteElement function in server/dia/audispatch.c in Network Audio System (NAS) before 1.8a SVN 237 allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via a large max_samples value. See also: CVE-2007-1544

The following code illustrates an integer overflow. The declaration of total integer as "unsigned short int" assumes that the length of the first and second arguments fits in such an integer.

include <stdlib.h> include <string.h> include <stdio.h> int main (int argc, char *const *argv) {
if (argc !=3){
printf("Usage: prog_name <string1> <string2>\n"); exit(-1);
} unsigned short int total; total = strlen(argv[1])+strlen(argv[2])+1; char * buff = (char *)malloc(total); strcpy(buff, argv[1]); strcpy(buff, argv[2]);
}

[R.92.4], [R.92.5]

+ Memberships
This MemberOf Relationships table shows additional CAPEC Categories and Views that reference this attack pattern as a member. This information is often useful in understanding where a attack pattern fits within the context of external information sources.
NatureTypeIDName
MemberOfCategoryCategory - A category in CAPEC is a collection of attack patterns based on some common characteristic. More specifically, it is an aggregation of attack patterns based on effect/intent (as opposed to actions or mechanisms, such an aggregation would be a meta attack pattern). An aggregation based on effect/intent is not an actionable attack and as such is not a pattern of attack behavior. Rather, it is a grouping of patterns based on some common criteria.336WASC-03 - Integer Overflows
+ References
[REF-131] J. Viega and G. McGraw. "Building Secure Software". Addison-Wesley. 2002.
[REF-546] "The OWASP Application Security Desk Reference". Integer overflow. The Open Web Application Security Project (OWASP). 2009. <http://www.owasp.org/index.php/Integer_overflow>.
[REF-547] Robert C. Seacord. "SAMATE - Software Assurance Metrics And Tool Evaluation". Test Case ID 1511. National Institute of Standards and Technology (NIST). 2006-05-22. <http://samate.nist.gov/SRD/view_testcase.php?tID=1511>.
[REF-548] Robert C. Seacord. "Secure Coding in C and C++". Page 152, Figure 5-1.
+ Content History
Submissions
Submission DateSubmitterOrganization
2014-06-23CAPEC Content TeamThe MITRE Corporation
Modifications
Modification DateModifierOrganization
2018-07-31CAPEC Content TeamThe MITRE Corporation
Updated References

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Page Last Updated or Reviewed: July 31, 2018