CWE-379: Creation of Temporary File in Directory with… | Glexia
CWE-379 (Creation of Temporary File in Directory with Insecure Permissions) weakness overview with consequences, detection methods, mitigations, related CVEs and…
Glexia's Take · Automated analysis
CWE-379: Creation of Temporary File in Directory with Insecure Permissions
Creation of Temporary File in Directory with Insecure Permissions represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.
Executive Impact
- Confidentiality: Read Application Data: Since the file is visible and the application which is using the temp file could be known, the attacker has gained information about what the user is doing at that time.
Developer Pattern
CWE-379 is the kind of defect developers can usually prevent with explicit validation, safer framework defaults, and tests that exercise hostile input or unsafe state transitions.
Automation confidence
high confidence from CWE-379, 4.20.
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Official CWE Definition
CWE-379: Creation of Temporary File in Directory with Insecure Permissions
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.
Developer And Remediation Guidance
How teams prevent and detect this weakness
Causes
- 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.,Similarly, the createTempFile() method used in the Java code creates a temp file that may be readable and writable to all users.,Additionally both methods used above place the file into a default directory. On UNIX systems the default directory is usually "/tmp" or "/var/tmp" and on Windows systems the default directory is usually "C:\\Windows\\Temp", which may be easily accessible to attackers, possibly enabling them to read and modify the contents of the temp file.
Remediation
- Requirements: Many contemporary languages have functions which properly handle this condition. Older C temp file functions are especially susceptible.
- Implementation: Try to store sensitive tempfiles in a directory which is not world readable -- i.e., per-user directories.
- Implementation: Avoid using vulnerable temp file functions.
Detection
- Automated Static Analysis: Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)
Mappings
Related CVEs, CWEs, and ATT&CK context
Related CWEs
ATT&CK Relevance
ATT&CK relevance is shown only when reviewed or responsibly inferred.