NULL Pointer Dereference

Opis

The product dereferences a pointer that it expects to be valid but is NULL.

Inne nazwy

NPD

Common abbreviation for Null Pointer Dereference

null deref

Common abbreviation for Null Pointer Dereference

NPE

Common abbreviation for Null Pointer Exception

nil pointer dereference

used for access of nil in Go programs

Skutki

• Availability

  DoS: Crash, Exit, or Restart

  NULL pointer dereferences usually result in the failure of the process unless exception handling (on some platforms) is available and implemented. Even when exception handling is being used, it can still be very difficult to return the software to a safe state of operation.

• Integrity, Confidentiality

  Execute Unauthorized Code or Commands; Read Memory; Modify Memory

  In rare circumstances, when NULL is equivalent to the 0x0 memory address and privileged code can access it, then writing or reading memory is possible, which may lead to code execution.

Zapobieganie

• Implementation

  For any pointers that could have been modified or provided from a function that can return NULL, check the pointer for NULL before use. When working with a multithreaded or otherwise asynchronous environment, ensure that proper locking APIs are used to lock before the check, and unlock when it has finished [REF-1484].

• Requirements

  Select a programming language that is not susceptible to these issues.

• Implementation

  Check the results of all functions that return a value and verify that the value is non-null before acting upon it.

  Skuteczność: Moderate

• 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 variables and other data stores, either during declaration or just before the first usage.

Przykłady podatności

• CVE-2024-41130 C++ library for LLM inference has NULL pointer dereference if a read operation fails
• CVE-2005-3274 race condition causes a table to be corrupted if a timer activates while it is being modified, leading to resultant NULL dereference; also involves locking.
• CVE-2002-1912 large number of packets leads to NULL dereference
• CVE-2005-0772 packet with invalid error status value triggers NULL dereference
• CVE-2009-4895 Chain: race condition for an argument value, possibly resulting in NULL dereference
• CVE-2020-29652 ssh component for Go allows clients to cause a denial of service (nil pointer dereference) against SSH servers.
• 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-2009-3547 Chain: race condition (CWE-362) might allow resource to be released before operating on it, leading to NULL dereference (CWE-476)
• CVE-2009-3620 Chain: some unprivileged ioctls do not verify that a structure has been initialized before invocation, leading to NULL dereference
• CVE-2009-2698 Chain: IP and UDP layers each track the same value with different mechanisms that can get out of sync, possibly resulting in a 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-2008-3597 Chain: game server can access player data structures before initialization has happened leading to NULL dereference
• CVE-2020-6078 Chain: The return value of a function returning a pointer is not checked for success (CWE-252) resulting in the later use of an uninitialized variable (CWE-456) and a null pointer dereference (CWE-476)
• CVE-2008-0062 Chain: a message having an unknown message type may cause a reference to uninitialized memory resulting in a null pointer dereference (CWE-476) or dangling pointer (CWE-825), possibly crashing the system or causing heap corruption.
• CVE-2008-5183 Chain: unchecked return value can lead to NULL dereference
• CVE-2004-0079 SSL software allows remote attackers to cause a denial of service (crash) via a crafted SSL/TLS handshake that triggers a null dereference.
• CVE-2004-0365 Network monitor allows remote attackers to cause a denial of service (crash) via a malformed RADIUS packet that triggers a null dereference.
• CVE-2003-1013 Network monitor allows remote attackers to cause a denial of service (crash) via a malformed Q.931, which triggers a null dereference.
• CVE-2003-1000 Chat client allows remote attackers to cause a denial of service (crash) via a passive DCC request with an invalid ID number, which causes a null dereference.
• CVE-2004-0389 Server allows remote attackers to cause a denial of service (crash) via malformed requests that trigger a null dereference.
• CVE-2004-0119 OS allows remote attackers to cause a denial of service (crash from null dereference) or execute arbitrary code via a crafted request during authentication protocol selection.
• CVE-2004-0458 Game allows remote attackers to cause a denial of service (server crash) via a missing argument, which triggers a null pointer dereference.
• CVE-2002-0401 Network monitor allows remote attackers to cause a denial of service (crash) or execute arbitrary code via malformed packets that cause a NULL pointer dereference.
• CVE-2001-1559 Chain: System call returns wrong value (CWE-393), leading to a resultant NULL dereference (CWE-476).

Słabość nadrzędna

• CWE-710 Improper Adherence to Coding Standards
• CWE-754 Improper Check for Unusual or Exceptional Conditions

Kiedy powstaje

• Implementation

Dotyczy

C, C++, Java, C#, Go

Źródła

1. Seven Pernicious Kingdoms: A Taxonomy of Software Security Errors — Katrina Tsipenyuk, Brian Chess, Gary McGraw, NIST, 2005
2. The CLASP Application Security Process — Secure Software, Inc., 2005
3. Null pointer / Null dereferencing — Wikipedia, 2019
4. Null Reference Creation and Null Pointer Dereference — Apple
5. NULL Pointer Dereference [CWE-476] — ImmuniWeb, 2012
6. D3FEND: D3-NPC Null Pointer Checking — D3FEND
7. AddressSanitizer