CWE-476: NULL Pointer Dereference

Description

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

Potential Impact

Demonstrative Examples

void host_lookup(char *user_supplied_addr){
                        struct hostent *hp;in_addr_t *addr;char hostname[64];in_addr_t inet_addr(const char *cp);
                           
                           /*routine that ensures user_supplied_addr is in the right format for conversion */
                           
                           validate_addr_form(user_supplied_addr);addr = inet_addr(user_supplied_addr);hp = gethostbyaddr( addr, sizeof(struct in_addr), AF_INET);strcpy(hostname, hp->h_name);
                     }

String cmd = System.getProperty("cmd");cmd = cmd.trim();

...
                     IntentFilter filter = new IntentFilter("com.example.URLHandler.openURL");MyReceiver receiver = new MyReceiver();registerReceiver(receiver, filter);
                     ...
                     
                     public class UrlHandlerReceiver extends BroadcastReceiver {
                        @Overridepublic void onReceive(Context context, Intent intent) {
                              if("com.example.URLHandler.openURL".equals(intent.getAction())) {String URL = intent.getStringExtra("URLToOpen");int length = URL.length();
                                 
                                 ...
                                 }
                           }
                     }

func HandleRequest(client http.Client, request *http.Request) (*http.Response, error) {
                     
                        response, err := client.Do(request)
                        defer response.Body.Close()
                        if err != nil {
                           
                              return nil, err
                           
                        }...
                     }

Mitigations & Prevention

Detection Methods

• Automated Dynamic Analysis Moderate — 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
• 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 su
• Automated Static Analysis High — Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then sea
• Automated Dynamic Analysis Moderate — Use tools that are integrated during compilation to insert runtime error-checking mechanisms related to memory safety errors, such as AddressSanitizer (ASan) for C/C++ [REF-1518].

Real-World CVE Examples

Showing 15 of 25 observed examples.

Related Weaknesses

Taxonomy Mappings

• 7 Pernicious Kingdoms: — Null Dereference
• CLASP: — Null-pointer dereference
• PLOVER: — Null Dereference (Null Pointer Dereference)
• OWASP Top Ten 2004: A9 — Denial of Service
• CERT C Secure Coding: EXP34-C — Do not dereference null pointers
• Software Fault Patterns: SFP7 — Faulty Pointer Use