CWE-379: Creation of Temporary File in Directory with Insecure Permissions

Extended Description

On some operating systems, the fact that the temporary file exists may be apparent to any user with sufficient privileges to access that directory. Since the file is visible, the application that is using the temporary file could be known. If one has access to list the processes on the system, the attacker has gained information about what the user is doing at that time. By correlating this with the applications the user is running, an attacker could potentially discover what a user's actions are. From this, higher levels of security could be breached.

Code Examples & CVEs

Demonstrative Examples

In the following code examples a temporary file is created and written to. After using the temporary file, the file is closed and deleted from the file system.

However, within this C/C++ code the method tmpfile() is used to create and open the temp file. The tmpfile() method works the same way as the fopen() method would with read/write permission, allowing attackers to read potentially sensitive information contained in the temp file or modify the contents of the file.

BadC

FILE *stream;if( (stream = tmpfile()) == NULL ) {                                                     perror("Could not open new temporary file\n");return (-1);                      }                      // write data to tmp file                      ...// remove tmp filermtmp();

In the following code examples a temporary file is created and written to. After using the temporary file, the file is closed and deleted from the file system.

BadJava

try {File temp = File.createTempFile("pattern", ".suffix");temp.deleteOnExit();BufferedWriter out = new BufferedWriter(new FileWriter(temp));out.write("aString");out.close();}catch (IOException e) {}

Observed CVE Examples (3)

CVE-2022-27818

A hotkey daemon written in Rust creates a domain socket file underneath /tmp, which is accessible by any user.

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CVE-2021-41989

analytic platform's repair functionality uses the %TEMP% folder of a user while running with higher privileges

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CVE-2021-21290

A Java-based application for a rapid-development framework uses File.createTempFile() to create a random temporary file with insecure default permissions.

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Source-backed guidance

Additional facts reviewed against primary or authoritative security sources.

Verify controls for CWE-379 with SSDF evidence

Use NIST SSDF verification and vulnerability-response practices to detect CWE-379, Creation of Temporary File in Directory with Insecure Permissions, throughout the product lifecycle. Derive review questions, static or dynamic checks, and negative tests from the CWE's causal behavior; define the components and lifecycle stages each check covers; and retain findings with enough evidence to distinguish the root cause from symptoms and impacts. Track escapes and false negatives, then improve the verification plan after every confirmed occurrence.

NIST SP 800-218 Secure Software Development Framework — National Institute of Standards and Technology

Address Creation of Temporary File in Directory with Insecure Permissions during Requirements

MITRE associates mitigation with Requirements, and Implementation; documented detection approaches include Automated Static Analysis; recorded impacts include Read Application Data. Use these source-defined anchors to turn CWE-379 into implementation, review, and verification checks for the affected component.

CWE-379: Creation of Temporary File in Directory with Insecure Permissions — MITRE CWE

Triage CWE-379 against known exploitation evidence

Use CISA's Known Exploited Vulnerabilities catalog to test whether a vulnerability mapped to CWE-379, Creation of Temporary File in Directory with Insecure Permissions, has evidence of exploitation in the wild. Confirm the CVE-to-CWE root-cause mapping independently before attaching the example, then capture the affected product, required action, and remediation deadline. A missing KEV match is not evidence that the weakness is unexploited, and a KEV entry must not be generalized to every occurrence of this CWE.

Known Exploited Vulnerabilities Catalog — Cybersecurity and Infrastructure Security Agency

Apply precise root-cause mapping to CWE-379

Apply MITRE's full root-cause mapping guidance when using CWE-379, Creation of Temporary File in Directory with Insecure Permissions. Separate weakness language from attacker prerequisites and technical impact, check the entry's abstraction and vulnerability-mapping notes, and prefer the most specific Base or Variant supported by the evidence. Record the rejected alternatives and require an independent review before the mapping is used for remediation trends or program metrics.

CVE to CWE Root Cause Mapping Guidance — MITRE CWE

Validate CWE-379 with root-cause mapping checks

Apply MITRE's root-cause mapping quick tips to CWE-379, Creation of Temporary File in Directory with Insecure Permissions. Confirm the finding describes the causal weakness rather than an impact or attack pattern, compare the abstraction and mapping notes with plausible alternatives, and have a second reviewer challenge the selection. Preserve the evidence and reasoning so recurring defects can be measured against one consistent identifier.

CVE to CWE Root Cause Mapping Quick Tips — MITRE CWE

Frequently Asked Questions

What is CWE-379: Creation of Temporary File in Directory with Insecure Permissions?+

CWE-379: Creation of Temporary File in Directory with Insecure Permissions is a Common Weakness Enumeration (CWE) entry maintained by MITRE. The product creates a temporary file in a directory whose permissions allow unintended actors to determine the file's existence or otherwise access that file. On some operating systems, the fact that the temporary file exists may be apparent to any user with sufficient privileges to access that directory. Since the file is visible, the application that is using the temporary file could be known. If one has access to list the processes on the system, the attacker has gained information about what the user is doing at that time. By correlating this with the applications the user is running, an attacker could potentially discover what a user's actions are. From this, higher levels of security could be breached.

What are the security consequences of Creation of Temporary File in Directory with Insecure Permissions?+

If exploited, CWE-379 (Creation of Temporary File in Directory with Insecure Permissions) it can compromise Confidentiality, leading to outcomes such as Read Application Data.

How do you prevent or mitigate Creation of Temporary File in Directory with Insecure Permissions?+

Recommended mitigations for CWE-379 include: Many contemporary languages have functions which properly handle this condition. Older C temp file functions are especially susceptible. Try to store sensitive tempfiles in a directory which is not world readable -- i.e., per-user directories. Avoid using vulnerable temp file functions.

Which programming languages are affected by Creation of Temporary File in Directory with Insecure Permissions?+

CWE-379 commonly affects Not Language-Specific. Note that weaknesses are often language-agnostic patterns, so secure coding practices apply broadly.

What are real-world examples of Creation of Temporary File in Directory with Insecure Permissions?+

MITRE documents real CVEs mapped to CWE-379, including CVE-2022-27818, CVE-2021-41989 and CVE-2021-21290. You can look up the full details of each CVE, including CVSS scores and remediation guidance, on our CVE Lookup tool.

What is the difference between a CWE and a CVE?+

A CWE (Common Weakness Enumeration) like CWE-379 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.

CWE-379: Creation of Temporary File in Directory with Insecure Permissions

Extended Description

Technical Details

Applicable To

Security Consequences

Scope

Impact

Mitigation Strategies

Phase

Description

Phase

Description

Phase

Description

Detection Methods

Code Examples & CVEs

Demonstrative Examples

Observed CVE Examples (3)

CWE Relationships

Parent Weaknesses

Source-backed guidance

Verify controls for CWE-379 with SSDF evidence

Address Creation of Temporary File in Directory with Insecure Permissions during Requirements

Triage CWE-379 against known exploitation evidence

Apply precise root-cause mapping to CWE-379

Validate CWE-379 with root-cause mapping checks

Frequently Asked Questions

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