Improper Clearing of Heap Memory Before Release ('Heap Inspection')

Opis

Using realloc() to resize buffers that store sensitive information can leave the sensitive information exposed to attack, because it is not removed from memory.

When sensitive data such as a password or an encryption key is not removed from memory, it could be exposed to an attacker using a "heap inspection" attack that reads the sensitive data using memory dumps or other methods. The realloc() function is commonly used to increase the size of a block of allocated memory. This operation often requires copying the contents of the old memory block into a new and larger block. This operation leaves the contents of the original block intact but inaccessible to the program, preventing the program from being able to scrub sensitive data from memory. If an attacker can later examine the contents of a memory dump, the sensitive data could be exposed.

Skutki

• Confidentiality, Other

  Read Memory; Other

  Be careful using vfork() and fork() in security sensitive code. The process state will not be cleaned up and will contain traces of data from past use.

Przykłady podatności

• CVE-2019-3733 Cryptography library does not clear heap memory before release

Słabość nadrzędna

• CWE-226 Sensitive Information in Resource Not Removed Before Reuse

Może prowadzić do

• CWE-669 Incorrect Resource Transfer Between Spheres

Kiedy powstaje

• Implementation

Dotyczy

Memory-Unsafe, C, C++

Źródła

1. Seven Pernicious Kingdoms: A Taxonomy of Software Security Errors — Katrina Tsipenyuk, Brian Chess, Gary McGraw, NIST, 2005