Weakness · High
CWE-825: Expired Pointer Dereference
What it is
The product dereferences a pointer that contains a location for memory that was previously valid, but is no longer valid.
- Severity (our rating)
- High
- Likelihood of exploit
- Not rated by MITRE
- Introduced during
- Implementation
- Exploited in the wild
- No CVE in CISA's catalog
In more detail
When a product releases memory, but it maintains a pointer to that memory, then the memory might be re-allocated at a later time. If the original pointer is accessed to read or write data, then this could cause the product to read or modify data that is in use by a different function or process. Depending on how the newly-allocated memory is used, this could lead to a denial of service, information exposure, or code execution.
What an attacker can do
- Read Memory (Confidentiality)
- DoS: Crash, Exit, or Restart (Availability)
- Execute Unauthorized Code or Commands (Integrity, Confidentiality, Availability)
How to prevent it
Architecture and Design
- Choose a language that provides automatic memory management.
Implementation
- When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.
How to find it
- Automated Static Analysis. 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 searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)
- Automated Dynamic Analysis. 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++.
H2 Security
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Start freeSource: MITRE Common Weakness Enumeration, CWE version 4.19.1. CWE is a trademark of The MITRE Corporation.