COMMON WEAKNESS ENUMERATIONIncomplete

CWE-616

Incomplete Identification of Uploaded File Variables (PHP)

The PHP application uses an old method for processing uploaded files by referencing the four global variables that are set for each file (e.g. $varname, $varname_size, $varname_name, $varname_type). These variables could be overwritten by attackers, causing the application to process unauthorized files.

Soyutlama

Variant

Yapı

Simple

Sömürü İhtimali

Medium

Problemi anla

Problem nedir?

The PHP application uses an old method for processing uploaded files by referencing the four global variables that are set for each file (e.g. $varname, $varname_size, $varname_name, $varname_type). These variables could be overwritten by attackers, causing the application to process unauthorized files.

Genişletilmiş açıklama

These global variables could be overwritten by POST requests, cookies, or other methods of populating or overwriting these variables. This could be used to read or process arbitrary files by providing values such as "/etc/passwd".

Kök neden

Problem nasıl ve ne zaman oluşur?

Yaşam döngüsü evresi

Implementation

Risk

Başarılı sömürü neye yol açar?

Read Files or DirectoriesModify Files or Directories

Etkilenen güvenlik alanları: Confidentiality, Integrity

Savunma

Nasıl önlenir ve çözülür?

Architecture and Design

Mimari ve tasarım yaklaşımı

Detay
Use PHP 4 or later.

Architecture and Design

Mimari ve tasarım yaklaşımı

Detay
If you must support older PHP versions, write your own version of is_uploaded_file() and run it against $HTTP_POST_FILES['userfile']))

Implementation

Uygulama aşaması savunması

Detay
For later PHP versions, reference uploaded files using the $HTTP_POST_FILES or $_FILES variables, and use is_uploaded_file() or move_uploaded_file() to ensure that you are dealing with an uploaded file.