Định nghĩa chính thức

Đặc điểm

Dữ liệu MITRE CWE chính thức

Dangling pointer — a pointer that no longer points to valid memory, often after it has been freed
UAF — commonly used acronym for Use After Free
Use-After-Free

Dữ liệu MITRE CWE chính thức

Tác động	Phạm vi	Diễn giải
Thay đổi bộ nhớ	Tính toàn vẹn	The use of previously freed memory may corrupt valid data, if the memory area in question has been allocated and used properly elsewhere.
Từ chối dịch vụ: sập, thoát hoặc khởi động lại	Tính sẵn sàng	If chunk consolidation occurs after the use of previously freed data, the process may crash when invalid data is used as chunk information.
Đọc bộ nhớ	Tính bí mật	Read operations on freed memory can sometimes leak sensitive information instead of causing a crash
Thực thi mã hoặc lệnh trái phép	Tính toàn vẹn, Tính bí mật, Tính sẵn sàng	If malicious data is entered before chunk consolidation can take place, it may be possible to take advantage of a write-what-where primitive to execute arbitrary code. If the newly allocated data happens to hold a class, in C++ for example, various function pointers may be scattered within the heap data. If one of these function pointers is overwritten with an address to valid shellcode, execution of arbitrary code can be achieved.

Dữ liệu MITRE CWE chính thức

Lựa chọn ngôn ngữ · Kiến trúc và thiết kếChoose a language that provides automatic memory management.
Giảm bề mặt tấn công · Hiện thực hóa · Hiệu quả: Phòng thủ nhiều lớpWhen 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.If a bug causes an attempted access of this pointer, then a NULL dereference could still lead to a crash or other unexpected behavior, but it will reduce or eliminate the risk of code execution.

Dữ liệu MITRE CWE chính thức

Phương pháp	Cách làm	Hiệu quả
Kiểm thử fuzzing	Fuzz testing (fuzzing) is a powerful technique for generating large numbers of diverse inputs - either randomly or algorithmically - and dynamically invoking the code with those inputs. Even with random inputs, it is often capable of generating unexpected results such as crashes, memory corruption, or resource consumption. Fuzzing effectively produces repeatable test cases that clearly indicate bugs, which helps developers to diagnose the issues.	Cao
Phân tích tĩnh tự động	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.)	Cao
Phân tích động tự động	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].Crafted inputs are necessary to reach the code containing the error, such as generated by fuzzers. Also, these tools may reduce performance, and they only report the error condition - not the original mistake that led to the error.	Khá

Dữ liệu MITRE CWE chính thức

Dưới đây là các lỗ hổng tiêu biểu liên quan đến CWE-416, dựa theo mức độ ưu tiên

Nguồn (5)