Improper Initialization| ID: 665 | Date: (C)2012-05-14 (M)2022-10-10 | | Type: weakness | Status: DRAFT | | Abstraction Type: Base |
Description The software does not initialize or incorrectly initializes a
resource, which might leave the resource in an unexpected state when it is
accessed or used. Extended DescriptionThis can have security implications when the associated resource is
expected to have certain properties or values, such as a variable that
determines whether a user has been authenticated or not. Likelihood of Exploit: Medium Applicable PlatformsLanguage Class: Language-independent Time Of Introduction Related Attack Patterns Common Consequences | Scope | Technical Impact | Notes |
|---|
| Confidentiality | Read memoryRead application
data | When reusing a resource such as memory or a program variable, the
original contents of that resource may not be cleared before it is sent
to an untrusted party. | | Access_Control | Bypass protection
mechanism | If security-critical decisions rely on a variable having a "0" or
equivalent value, and the programming language performs this
initialization on behalf of the programmer, then a bypass of security
may occur. | | Availability | DoS: crash / exit /
restart | The uninitialized data may contain values that cause program flow to
change in ways that the programmer did not intend. For example, if an
uninitialized variable is used as an array index in C, then its previous
contents may produce an index that is outside the range of the array,
possibly causing a crash or an exit in other environments. |
Detection Methods | Name | Description | Effectiveness | Notes |
|---|
| Automated Dynamic Analysis | 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.Initialization problems may be detected with a stress-test by calling
the software simultaneously from a large number of threads or processes,
and look for evidence of any unexpected behavior. The software's
operation may slow down, but it should not become unstable, crash, or
generate incorrect results. | Moderate | | | Manual Dynamic Analysis | Identify error conditions that are not likely to occur during normal
usage and trigger them. For example, run the program under low memory
conditions, run with insufficient privileges or permissions, interrupt a
transaction before it is completed, or disable connectivity to basic
network services such as DNS. Monitor the software for any unexpected
behavior. If you trigger an unhandled exception or similar error that
was discovered and handled by the application's environment, it may
still indicate unexpected conditions that were not handled by the
application itself. | | |
Potential Mitigations | Phase | Strategy | Description | Effectiveness | Notes |
|---|
| Requirements | Language Selection | Use a language that does not allow this weakness to occur or provides
constructs that make this weakness easier to avoid.For example, in Java, if the programmer does not explicitly initialize
a variable, then the code could produce a compile-time error (if the
variable is local) or automatically initialize the variable to the
default value for the variable's type. In Perl, if explicit
initialization is not performed, then a default value of undef is
assigned, which is interpreted as 0, false, or an equivalent value
depending on the context in which the variable is accessed. | | | | Architecture and Design | | Identify all variables and data stores that receive information from
external sources, and apply input validation to make sure that they are
only initialized to expected values. | | | | Implementation | | Explicitly initialize all your variables and other data stores, either
during declaration or just before the first usage. | | | | Implementation | | Pay close attention to complex conditionals that affect
initialization, since some conditions might not perform the
initialization. | | | | Implementation | | Avoid race conditions (CWE-362) during initialization routines. | | | | Build and Compilation | | Run or compile your software with settings that generate warnings
about uninitialized variables or data. | | | | Testing | | Use automated static analysis tools that target this type of weakness.
Many modern techniques use data flow analysis to minimize the number of
false positives. This is not a perfect solution, since 100% accuracy and
coverage are not feasible. | | |
Relationships | Related CWE | Type | View | Chain |
|---|
| CWE-665 ChildOf CWE-889 | Category | CWE-888 | |
Demonstrative Examples (Details) - Here, a boolean initiailized field is consulted to ensure that
initialization tasks are only completed once. However, the field is
mistakenly set to true during static initialization, so the initialization
code is never reached.
- The following code intends to concatenate a string to a variable and
print the string.
- The following code intends to limit certain operations to the
administrator only. (Demonstrative Example Id DX-54)
Observed Examples - CVE-2001-1471 : chain: an invalid value prevents a library file from being included, skipping initialization of key variables, leading to resultant eval injection.
- CVE-2008-3637 : Improper error checking in protection mechanism produces an uninitialized variable, allowing security bypass and code execution.
- CVE-2008-4197 : Use of uninitialized memory may allow code execution.
- CVE-2008-2934 : Free of an uninitialized pointer leads to crash and possible code execution.
- CVE-2007-3749 : OS kernel does not reset a port when starting a setuid program, allowing local users to access the port and gain privileges.
- CVE-2008-0063 : Product does not clear memory contents when generating an error message, leading to information leak.
- CVE-2008-0062 : Lack of initialization triggers NULL pointer dereference or double-free.
- CVE-2008-0081 : Uninitialized variable leads to code execution in popular desktop application.
- CVE-2008-3688 : chain: Uninitialized variable leads to infinite loop.
- CVE-2008-3475 : chain: Improper initialization leads to memory corruption.
- CVE-2008-5021 : Composite: race condition allows attacker to modify an object while it is still being initialized, causing software to access uninitialized memory.
- CVE-2005-1036 : Permission bitmap is not properly initialized, leading to resultant privilege elevation or DoS.
- CVE-2008-3597 : chain: game server can access player data structures before initialization has happened leading to NULL dereference
- CVE-2009-2692 : chain: uninitialized function pointers can be dereferenced allowing code execution
- CVE-2009-0949 : chain: improper initialization of memory can lead to NULL dereference
- CVE-2009-3620 : chain: some unprivileged ioctls do not verify that a structure has been initialized before invocation, leading to NULL dereference
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 | | Incorrect initialization | | | CERT C Secure Coding | ARR02-C | Explicitly specify array bounds, even if implicitly defined by
an initializer | | | CERT C Secure Coding | MEM09-C | Do not assume memory allocation routines initialize
memory | | | CERT Java Secure Coding | DCL00-J | Prevent class initialization cycles | | | CERT C++ Secure Coding | ARR02-CPP | Explicitly specify array bounds, even if implicitly defined by
an initializer | | | CERT C++ Secure Coding | MEM09-CPP | Do not assume memory allocation routines initialize
memory | |
References: - mercy .Exploiting Uninitialized Data. Published on Jan 2006.
- Microsoft Security Vulnerability Research &
Defense .MS08-014 : The Case of the Uninitialized Stack Variable
Vulnerability. 2008-03-11.
- Mark Dowd John McDonald Justin Schuh .The Art of Software Security Assessment 1st Edition. Addison Wesley. Section:'Chapter 7, "Variable Initialization", Page
312.'. Published on 2006.
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