Description
The product stores, transfers, or shares a resource that contains sensitive information, but it does not properly remove that information before the product makes the resource available to unauthorized actors.
Resources that may contain sensitive data include documents, packets, messages, databases, etc. While this data may be useful to an individual user or small set of users who share the resource, it may need to be removed before the resource can be shared outside of the trusted group. The process of removal is sometimes called cleansing or scrubbing. For example, a product for editing documents might not remove sensitive data such as reviewer comments or the local pathname where the document is stored. Or, a proxy might not remove an internal IP address from headers before making an outgoing request to an Internet site.
Potential Impact
Confidentiality
Read Files or Directories, Read Application Data
Demonstrative Examples
// API flag, output JSON if set
$json = $_GET['json']$username = $_GET['user']if(!$json){
$record = getUserRecord($username);foreach($record as $fieldName => $fieldValue){
if($fieldName == "email_address") {
// skip displaying user emails
continue;
}else{writeToHtmlPage($fieldName,$fieldValue);}
}
}else{$record = getUserRecord($username);echo json_encode($record);}Mitigations & Prevention
Clearly specify which information should be regarded as private or sensitive, and require that the product offers functionality that allows the user to cleanse the sensitive information from the resource before it is published or exported to other parties.
Compartmentalize the system to have "safe" areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area. Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least
Some tools can automatically analyze documents to redact, strip, or "sanitize" private information, although some human review might be necessary. Tools may vary in terms of which document formats can be processed. When calling an external program to automatically generate or convert documents, invoke the program with any available options that avoid generating sensitive metadata. Some formats have well-defined fields that could contain private data, such as
Use naming conventions and strong types to make it easier to spot when sensitive data is being used. When creating structures, objects, or other complex entities, separate the sensitive and non-sensitive data as much as possible.
Avoid errors related to improper resource shutdown or release (CWE-404), which may leave the sensitive data within the resource if it is in an incomplete state.
Detection Methods
- Automated Static Analysis — Tools are available to analyze documents (such as PDF, Word, etc.) to look for private information such as names, addresses, etc.
Real-World CVE Examples
| CVE ID | Description |
|---|---|
| CVE-2023-1974 | product does not remove EXIF data from images, which can include GPS coordinates |
| CVE-2020-26220 | Customer relationship management (CRM) product does not strip Exif data from images |
| CVE-2019-3733 | Cryptography library does not clear heap memory before release |
| CVE-2005-0406 | Some image editors modify a JPEG image, but the original EXIF thumbnail image is left intact within the JPEG. (Also an interaction error). |
| CVE-2002-0704 | NAT feature in firewall leaks internal IP addresses in ICMP error messages. |
Related Weaknesses
Taxonomy Mappings
- PLOVER: — Cross-Boundary Cleansing Infoleak
Frequently Asked Questions
What is CWE-212?
CWE-212 (Improper Removal of Sensitive Information Before Storage or Transfer) is a software weakness identified by MITRE's Common Weakness Enumeration. It is classified as a Base-level weakness. The product stores, transfers, or shares a resource that contains sensitive information, but it does not properly remove that information before the product makes the resource available to unauthorize...
How can CWE-212 be exploited?
Attackers can exploit CWE-212 (Improper Removal of Sensitive Information Before Storage or Transfer) to read files or directories, read application data. This weakness is typically introduced during the Architecture and Design, Implementation, Operation phase of software development.
How do I prevent CWE-212?
Key mitigations include: Clearly specify which information should be regarded as private or sensitive, and require that the product offers functionality that allows the user to cleanse the sensitive information from the resou
What is the severity of CWE-212?
CWE-212 is classified as a Base-level weakness (Medium abstraction). It has been observed in 5 real-world CVEs.