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.
View on MITREThese 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".
Use PHP 4 or later.
If you must support older PHP versions, write your own version of is_uploaded_file() and run it against $HTTP_POST_FILES['userfile']))
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.
No detection method information available for this CWE.
As of 2006, the "four globals" method is probably in sharp decline, but older PHP applications could have this issue.
In the "four globals" method, PHP sets the following 4 global variables (where "varname" is application-dependent):
Forum does not properly verify whether a file was uploaded or if the associated variables were set by POST, allowing remote attackers to read arbitrary files.
View DetailsProduct doesn't check if the variables for an upload were set by uploading the file, or other methods such as $_POST.
View DetailsCWE-616: Incomplete Identification of Uploaded File Variables (PHP) is a Common Weakness Enumeration (CWE) entry maintained by MITRE. 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. 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".
If exploited, CWE-616 (Incomplete Identification of Uploaded File Variables (PHP)) it can compromise Confidentiality and Integrity, leading to outcomes such as Read Files or Directories and Modify Files or Directories.
Recommended mitigations for CWE-616 include: Use PHP 4 or later. If you must support older PHP versions, write your own version of is_uploaded_file() and run it against $HTTP_POST_FILES['userfile'])) 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.
CWE-616 commonly affects PHP. Note that weaknesses are often language-agnostic patterns, so secure coding practices apply broadly.
MITRE documents real CVEs mapped to CWE-616, including CVE-2002-1460, CVE-2002-1759 and CVE-2002-1710. You can look up the full details of each CVE, including CVSS scores and remediation guidance, on our CVE Lookup tool.
A CWE (Common Weakness Enumeration) like CWE-616 describes a category of software weakness — the underlying flaw type. A CVE (Common Vulnerabilities and Exposures) identifies a specific, real-world vulnerability in a particular product. In short, a CWE is the kind of mistake, and a CVE is an instance of that mistake being found in software.