Détail du CWE-1389

The product parses numeric input assuming base 10 (decimal) values, but it does not account for inputs that use a different base number (radix).

Frequently, a numeric input that begins with "0" is treated as octal, or "0x" causes it to be treated as hexadecimal, e.g. by the inet_addr() function. For example, "023" (octal) is 35 decimal, or "0x31" is 49 decimal. Other bases may be used as well. If the developer assumes decimal-only inputs, the code could produce incorrect numbers when the inputs are parsed using a different base. This can result in unexpected and/or dangerous behavior. For example, a "0127.0.0.1" IP address is parsed as octal due to the leading "0", whose numeric value would be the same as 87.0.0.1 (decimal), where the developer likely expected to use 127.0.0.1.

The consequences vary depending on the surrounding code in which this weakness occurs, but they can include bypassing network-based access control using unexpected IP addresses or netmasks, or causing apparently-symbolic identifiers to be processed as if they are numbers. In web applications, this can enable bypassing of SSRF restrictions.

Modes d'introduction

Implementation : Input validation used may assume decimal bases during conditional checks, when it may not always be the case.
Implementation : The application may rely on a service that supports different numerical bases.

Plateformes applicables

Langue

Class: Not Language-Specific (Undetermined)

Technologies

Class: Not Technology-Specific (Undetermined)

Conséquences courantes

Exemples observés

Mesures d’atténuation potentielles

Phases : Implementation
If only decimal-based values are expected in the application, conditional checks should be created in a way that prevent octal or hexadecimal strings from being checked. This can be achieved by converting any numerical string to an explicit base-10 integer prior to the conditional check, to prevent octal or hex values from ever being checked against the condition.
Phases : Implementation
If various numerical bases do need to be supported, check for leading values indicating the non-decimal base you wish to support (such as 0x for hex) and convert the numeric strings to integers of the respective base. Reject any other alternative-base string that is not intentionally supported by the application.
Phases : Implementation
If regular expressions are used to validate IP addresses, ensure that they are bounded using ^ and $ to prevent base-prepended IP addresses from being matched.

Notes de cartographie des vulnérabilités

Justification : This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.
Commentaire : Carefully read both the name and description to ensure that this mapping is an appropriate fit. Do not try to 'force' a mapping to a lower-level Base/Variant simply to comply with this preferred level of abstraction.

Références

REF-1284

Universal "netmask" npm package, used by 270,000+ projects, vulnerable to octal input data
Sick Codes.
https://sick.codes/universal-netmask-npm-package-used-by-270000-projects-vulnerable-to-octal-input-data-server-side-request-forgery-remote-file-inclusion-local-file-inclusion-and-more-cve-2021-28918/

Soumission

Modifications