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Remote file include
RFI — The Remote File Inclusion (RFI) acronym is often used by vulnerability researchers.
Local file inclusion — This term is frequently used in cases in which remote download is disabled, or when the first part of the filename is not under the attacker's control, which forces use of relative path traversal (CWE-23) attack techniques to access files that may contain previously-injected PHP code, such as web access logs.

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Hiện thực hóa: REALIZATION: This weakness is caused during implementation of an architectural security tactic.

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Dữ liệu MITRE CWE chính thức

Tác động	Phạm vi	Diễn giải
Thực thi mã hoặc lệnh trái phép	Tính toàn vẹn, Tính bí mật, Tính sẵn sàng	The attacker may be able to specify arbitrary code to be executed from a remote location. Alternatively, it may be possible to use normal program behavior to insert php code into files on the local machine which can then be included and force the code to execute since php ignores everything in the file except for the content between php specifiers.

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Dữ liệu MITRE CWE chính thức

Thư viện hoặc framework · Kiến trúc và thiết kếUse a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid [REF-1482].
Áp đặt quy tắc bằng chuyển đổi · Kiến trúc và thiết kếWhen the set of acceptable objects, such as filenames or URLs, is limited or known, create a mapping from a set of fixed input values (such as numeric IDs) to the actual filenames or URLs, and reject all other inputs. For example, ID 1 could map to "inbox.txt" and ID 2 could map to "profile.txt". Features such as the ESAPI AccessReferenceMap [REF-185] provide this capability.
Kiến trúc và thiết kếFor any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.
Môi trường cô lập (sandbox/jail) · Kiến trúc và thiết kế, Vận hành · Hiệu quả: Hạn chếRun the code in a "jail" or similar sandbox environment that enforces strict boundaries between the process and the operating system. This may effectively restrict which files can be accessed in a particular directory or which commands can be executed by the software. OS-level examples include the Unix chroot jail, AppArmor, and SELinux. In general, managed code may provide some protection. For example, java.io.FilePermission in the Java SecurityManager allows the software to specify restrictions on file operations. This may not be a feasible solution, and it only limits the impact to the operating system; the rest of the application may still be subject to compromise. Be careful to avoid CWE-243 and other weaknesses related to jails.The effectiveness of this mitigation depends on the prevention capabilities of the specific sandbox or jail being used and might only help to reduce the scope of an attack, such as restricting the attacker to certain system calls or limiting the portion of the file system that can be accessed.
Gia cố môi trường · Kiến trúc và thiết kế, Vận hànhRun your code using the lowest privileges that are required to accomplish the necessary tasks [REF-76]. If possible, create isolated accounts with limited privileges that are only used for a single task. That way, a successful attack will not immediately give the attacker access to the rest of the software or its environment. For example, database applications rarely need to run as the database administrator, especially in day-to-day operations.
Kiểm tra dữ liệu đầu vào · Hiện thực hóa · Hiệu quả: CaoAssume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does. When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue." Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright. When validating filenames, use stringent lists that limit the character set to be used. If feasible, only allow a single "." character in the filename to avoid weaknesses such as CWE-23, and exclude directory separators such as "/" to avoid CWE-36. Use a list of allowable file extensions, which will help to avoid CWE-434. Do not rely exclusively on a filtering mechanism that removes potentially dangerous characters. This is equivalent to a denylist, which may be incomplete (CWE-184). For example, filtering "/" is insufficient protection if the filesystem also supports the use of "\" as a directory separator. Another possible error could occur when the filtering is applied in a way that still produces dangerous data (CWE-182). For example, if "../" sequences are removed from the ".../...//" string in a sequential fashion, two instances of "../" would be removed from the original string, but the remaining characters would still form the "../" string.
Giảm bề mặt tấn công · Kiến trúc và thiết kế, Vận hànhStore library, include, and utility files outside of the web document root, if possible. Otherwise, store them in a separate directory and use the web server's access control capabilities to prevent attackers from directly requesting them. One common practice is to define a fixed constant in each calling program, then check for the existence of the constant in the library/include file; if the constant does not exist, then the file was directly requested, and it can exit immediately. This significantly reduces the chance of an attacker being able to bypass any protection mechanisms that are in the base program but not in the include files. It will also reduce the attack surface.
Giảm bề mặt tấn công · Kiến trúc và thiết kế, Hiện thực hóaUnderstand all the potential areas where untrusted inputs can enter your software: parameters or arguments, cookies, anything read from the network, environment variables, reverse DNS lookups, query results, request headers, URL components, e-mail, files, filenames, databases, and any external systems that provide data to the application. Remember that such inputs may be obtained indirectly through API calls. Many file inclusion problems occur because the programmer assumed that certain inputs could not be modified, especially for cookies and URL components.
Tường lửa · Vận hành · Hiệu quả: KháUse an application firewall that can detect attacks against this weakness. It can be beneficial in cases in which the code cannot be fixed (because it is controlled by a third party), as an emergency prevention measure while more comprehensive software assurance measures are applied, or to provide defense in depth [REF-1481].An application firewall might not cover all possible input vectors. In addition, attack techniques might be available to bypass the protection mechanism, such as using malformed inputs that can still be processed by the component that receives those inputs. Depending on functionality, an application firewall might inadvertently reject or modify legitimate requests. Finally, some manual effort may be required for customization.
Gia cố môi trường · Vận hành, Hiện thực hóaDevelop and run your code in the most recent versions of PHP available, preferably PHP 6 or later. Many of the highly risky features in earlier PHP interpreters have been removed, restricted, or disabled by default.
Gia cố môi trường · Vận hành, Hiện thực hóaWhen using PHP, configure the application so that it does not use register_globals. During implementation, develop the application so that it does not rely on this feature, but be wary of implementing a register_globals emulation that is subject to weaknesses such as CWE-95, CWE-621, and similar issues. Often, programmers do not protect direct access to files intended only to be included by core programs. These include files may assume that critical variables have already been initialized by the calling program. As a result, the use of register_globals combined with the ability to directly access the include file may allow attackers to conduct file inclusion attacks. This remains an extremely common pattern as of 2009.
Gia cố môi trường · Vận hành · Hiệu quả: CaoSet allow_url_fopen to false, which limits the ability to include files from remote locations.Be aware that some versions of PHP will still accept ftp:// and other URI schemes. In addition, this setting does not protect the code from path traversal attacks (CWE-22), which are frequently successful against the same vulnerable code that allows remote file inclusion.

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Dữ liệu MITRE CWE chính thức

Phương pháp	Cách làm	Hiệu quả
Phân tích thủ công	Manual white-box analysis can be very effective for finding this issue, since there is typically a relatively small number of include or require statements in each program.	Cao
Phân tích tĩnh tự động	The external control or influence of filenames can often be detected using automated static analysis that models data flow within the product. Automated static analysis might not be able to recognize when proper input validation is being performed, leading to false positives - i.e., warnings that do not have any security consequences or require any code changes. If the program uses a customized input validation library, then some tools may allow the analyst to create custom signatures to detect usage of those routines.	-

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Dữ liệu MITRE CWE chính thức

Dưới đây là các lỗ hổng tiêu biểu liên quan đến CWE-98, dựa theo mức độ ưu tiên

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MITRE CWE

CWE Terms of Use

CWE-98: Improper Control of Filename for Include/Require Statement in PHP Program ('PHP Remote File Inclusion')

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