Improper Initialization

Opis

The product does not initialize or incorrectly initializes a resource, which might leave the resource in an unexpected state when it is accessed or used.

This 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.

Skutki

• Confidentiality

  Read Memory; Read 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, or 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.

Zapobieganie

• 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 product with settings that generate warnings about uninitialized variables or data.

Przykłady podatności

• 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 Chain: Bypass of access restrictions due to improper authorization (CWE-862) of a user results from an improperly initialized (CWE-909) I/O permission bitmap
• CVE-2008-3597 chain: game server can access player data structures before initialization has happened leading to NULL dereference
• CVE-2009-2692 Chain: Use of an unimplemented network socket operation pointing to an uninitialized handler function (CWE-456) causes a crash because of a null pointer dereference (CWE-476)
• 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

Słabość nadrzędna

• CWE-664 Improper Control of a Resource Through its Lifetime

Słabości podrzędne

• CWE-455 Non-exit on Failed Initialization
• CWE-456 Missing Initialization of a Variable
• CWE-457 Use of Uninitialized Variable
• CWE-770 Allocation of Resources Without Limits or Throttling
• CWE-908 Use of Uninitialized Resource
• CWE-909 Missing Initialization of Resource
• CWE-1188 Initialization of a Resource with an Insecure Default
• CWE-1279 Cryptographic Operations are run Before Supporting Units are Ready
• CWE-1419 Incorrect Initialization of Resource
• CWE-1434 Insecure Setting of Generative AI/ML Model Inference Parameters

Kiedy powstaje

• Implementation — This weakness can occur in code paths that are not well-tested, such as rare error conditions. This is because the use of uninitialized data would be noticed as a bug during frequently-used functionality.
• Operation

Dotyczy

Not Language-Specific

Źródła

1. Exploiting Uninitialized Data — mercy, 2006
2. MS08-014 : The Case of the Uninitialized Stack Variable Vulnerability — Microsoft Security Vulnerability Research & Defense, 2008
3. The Art of Software Security Assessment — Mark Dowd, John McDonald, Justin Schuh, Chapter 7, "Variable Initialization", Page 312, Addison Wesley, 2006