Integer Overflow or WraparoundID: 190 | Date: (C)2012-05-14 (M)2022-10-10 |
Type: weakness | Status: INCOMPLETE |
Abstraction Type: Base |
Description
The software performs a calculation that can produce an integer
overflow or wraparound, when the logic assumes that the resulting value will
always be larger than the original value. This can introduce other weaknesses
when the calculation is used for resource management or execution
control.
Extended DescriptionAn integer overflow or wraparound occurs when an integer value is
incremented to a value that is too large to store in the associated
representation. When this occurs, the value may wrap to become a very small
or negative number. While this may be intended behavior in circumstances
that rely on wrapping, it can have security consequences if the wrap is
unexpected. This is especially the case if the integer overflow can be
triggered using user-supplied inputs. This becomes security-critical when
the result is used to control looping, make a security decision, or
determine the offset or size in behaviors such as memory allocation,
copying, concatenation, etc.
Likelihood of Exploit: Medium
Applicable PlatformsLanguage Class: Language-independent
Time Of Introduction
Related Attack Patterns
Common Consequences
Scope | Technical Impact | Notes |
---|
Availability | DoS: crash / exit /
restartDoS: resource consumption
(CPU)DoS: resource consumption
(memory)DoS: instability | This weakness will generally lead to undefined behavior and therefore
crashes. In the case of overflows involving loop index variables, the
likelihood of infinite loops is also high. |
Integrity | Modify memory | If the value in question is important to data (as opposed to flow),
simple data corruption has occurred. Also, if the wrap around results in
other conditions such as buffer overflows, further memory corruption may
occur. |
ConfidentialityAvailabilityAccess_Control | Execute unauthorized code or
commandsBypass protection
mechanism | This weakness can sometimes trigger buffer overflows which can be used
to execute arbitrary code. This is usually outside the scope of a
program's implicit security policy. |
Detection Methods
Name | Description | Effectiveness | Notes |
---|
Automated Static Analysis | This weakness can often be detected using automated static analysis
tools. Many modern tools use data flow analysis or constraint-based
techniques to minimize the number of false positives. | High | |
Black Box | Sometimes, evidence of this weakness can be detected using dynamic
tools and techniques that interact with the software using large test
suites with many diverse inputs, such as fuzz testing (fuzzing),
robustness testing, and fault injection. The software's operation may
slow down, but it should not become unstable, crash, or generate
incorrect results. | Moderate | |
Manual Analysis | This weakness can be detected using tools and techniques that require
manual (human) analysis, such as penetration testing, threat modeling,
and interactive tools that allow the tester to record and modify an
active session.Specifically, manual static analysis is useful for evaluating the
correctness of allocation calculations. This can be useful for detecting
overflow conditions (CWE-190) or similar weaknesses that might have
serious security impacts on the program. | High | |
Potential Mitigations
Phase | Strategy | Description | Effectiveness | Notes |
---|
Requirements | | Ensure that all protocols are strictly defined, such that all
out-of-bounds behavior can be identified simply, and require strict
conformance to the protocol. | | |
Requirements | Language Selection | Use a language that does not allow this weakness to occur or provides
constructs that make this weakness easier to avoid.If possible, choose a language or compiler that performs automatic
bounds checking. | | |
Architecture and Design | Libraries or Frameworks | Use a vetted library or framework that does not allow this weakness to
occur or provides constructs that make this weakness easier to
avoid.Use libraries or frameworks that make it easier to handle numbers
without unexpected consequences.Examples include safe integer handling packages such as SafeInt (C++)
or IntegerLib (C or C++). [R.190.5] | | |
Implementation | Input Validation | Perform input validation on any numeric input by ensuring that it is
within the expected range. Enforce that the input meets both the minimum
and maximum requirements for the expected range.Use unsigned integers where possible. This makes it easier to perform
sanity checks for integer overflows. When signed integers are required,
ensure that the range check includes minimum values as well as maximum
values. | | |
Implementation | | Understand the programming language's underlying representation and
how it interacts with numeric calculation (CWE-681). Pay close attention
to byte size discrepancies, precision, signed/unsigned distinctions,
truncation, conversion and casting between types, "not-a-number"
calculations, and how the language handles numbers that are too large or
too small for its underlying representation. [R.190.3]Also be careful to account for 32-bit, 64-bit, and other potential
differences that may affect the numeric representation. | | |
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. | | |
Implementation | Compilation or Build Hardening | Examine compiler warnings closely and eliminate problems with
potential security implications, such as signed / unsigned mismatch in
memory operations, or use of uninitialized variables. Even if the
weakness is rarely exploitable, a single failure may lead to the
compromise of the entire system. | | |
RelationshipsInteger overflows can be primary to buffer overflows.
Related CWE | Type | View | Chain |
---|
CWE-190 ChildOf CWE-885 | Category | CWE-888 | |
Demonstrative Examples (Details)
- In this example the method determineFirstQuarterRevenue is used to
determine the first quarter revenue for an accounting/business application.
The method retrieves the monthly sales totals for the first three months of
the year, calculates the first quarter sales totals from the monthly sales
totals, calculates the first quarter revenue based on the first quarter
sales, and finally saves the first quarter revenue results to the
database.
- Integer overflows can be complicated and difficult to detect. The
following example is an attempt to show how an integer overflow may lead to
undefined looping behavior:
- The following code excerpt from OpenSSH 3.3 demonstrates a classic
case of integer overflow:
- The following image processing code allocates a table for
images. (Demonstrative Example Id DX-33)
Observed Examples
- CVE-2010-2753 : chain: integer overflow leads to use-after-free
- CVE-2002-0391 : Integer overflow via a large number of arguments.
- CVE-2002-0639 : Integer overflow in OpenSSH as listed in the demonstrative examples.
- CVE-2005-1141 : Image with large width and height leads to integer overflow.
- CVE-2005-0102 : Length value of -1 leads to allocation of 0 bytes and resultant heap overflow.
- CVE-2004-2013 : Length value of -1 leads to allocation of 0 bytes and resultant heap overflow.
For more examples, refer to CVE relations in the bottom box.
White Box Definitions None
Black Box Definitions None
Taxynomy Mappings
Taxynomy | Id | Name | Fit |
---|
PLOVER | | Integer overflow (wrap or wraparound) | |
7 Pernicious Kingdoms | | Integer Overflow | |
CLASP | | Integer overflow | |
CERT C Secure Coding | INT03-C | Use a secure integer library | |
CERT C Secure Coding | INT30-C | Ensure that unsigned integer operations do not
wrap | |
CERT C Secure Coding | INT32-C | Ensure that operations on signed integers do not result in
overflow | |
CERT C Secure Coding | INT35-C | Evaluate integer expressions in a larger size before comparing
or assigning to that size | |
CERT C Secure Coding | MEM07-C | Ensure that the arguments to calloc(), when multiplied, can be
represented as a size_t | |
CERT C Secure Coding | MEM35-C | Allocate sufficient memory for an object | |
WASC | 3 | Integer Overflows | |
CERT C++ Secure Coding | INT03-CPP | Use a secure integer library | |
CERT C++ Secure Coding | INT30-CPP | Ensure that unsigned integer operations do not
wrap | |
CERT C++ Secure Coding | INT32-CPP | Ensure that operations on signed integers do not result in
overflow | |
CERT C++ Secure Coding | INT35-CPP | Evaluate integer expressions in a larger size before comparing
or assigning to that size | |
CERT C++ Secure Coding | MEM07-CPP | Ensure that the arguments to calloc(), when multiplied, can be
represented as a size_t | |
CERT C++ Secure Coding | MEM35-CPP | Allocate sufficient memory for an object | |
References:
- Yves Younan .An overview of common programming security vulnerabilities and
possible solutions. Student thesis section 5.4.3. Published on August 2003.
- blexim .Basic Integer Overflows. Phrack - Issue 60, Chapter 10.
- M. Howard D. LeBlanc .Writing Secure Code 2nd Edition. Microsoft. Section:'Chapter 20, "Integer Overflows" Page 620'. Published on 2002.
- Michael Howard David LeBlanc John Viega .24 Deadly Sins of Software Security. McGraw-Hill. Section:'"Sin 7: Integer Overflows." Page 119'. Published on 2010.
- David LeBlanc Niels Dekker .SafeInt.
- Johannes Ullrich .Top 25 Series - Rank 17 - Integer Overflow Or
Wraparound. SANS Software Security Institute. 2010-03-18.
- Mark Dowd John McDonald Justin Schuh .The Art of Software Security Assessment 1st Edition. Addison Wesley. Section:'Chapter 6, "Signed Integer Boundaries", Page
220.'. Published on 2006.