CWE-909: Missing Initialization of Resource

How it's found

Missing Initialization of Resource describes a general pattern rather than a single fixed bug. Testers use a mix of static analysis and manual code review to find where a target's code matches this pattern, then confirm exploitability by hand.

Many resources require initialization before they can be properly used. If a resource is not initialized, it could contain unpredictable or expired data, or it could be initialized to defaults that are invalid. This can have security implications when the resource is expected to have certain properties or values.

Vulnerable vs. safe

test_string = "Hello World!";char *test_string;if (i != err_val){}printf("%s", test_string);

test_string = "Hello World!";char *test_string = "Done at the beginning";if (i != err_val){}printf("%s", test_string);

Consequences

• 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.
• DoS: Crash, Exit, or Restart: The uninitialized resource may contain values that cause program flow to change in ways that the programmer did not intend.

Mitigations

• Implementation: Explicitly initialize the resource before use. If this is performed through an API function or standard procedure, follow all specified steps.
• Implementation: Pay close attention to complex conditionals that affect initialization, since some branches 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.

Where this fits in a TurboPentest engagement

This weakness is not covered by the automated black-box pentest. IntegSec pentesters cover it in a manual engagement.

Frequently asked questions

Related CWEs

• Class weakness
  CWE-665: Improper Initialization