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.)
CWE-313 Variant Draft
Cleartext Storage in a File or on Disk
This vulnerability occurs when an application writes sensitive data, such as passwords or personal information, directly to a file or disk without using encryption.
Definition
What is CWE-313?
This vulnerability occurs when an application writes sensitive data, such as passwords or personal information, directly to a file or disk without using encryption.
When sensitive data is stored in plain text, anyone with access to the file—or even the raw disk—can read it directly. This includes attackers who have gained system access, malicious insiders, or even system administrators performing routine maintenance. The risk isn't limited to standard file permissions; physical access to a storage device or the ability to read disk sectors can also expose the unprotected information.
Even if the data appears scrambled or uses a simple encoding like Base64, it does not provide real security. Attackers can easily detect common encoding schemes and reverse them to recover the original cleartext. True protection requires strong, standard encryption with a securely managed key, not just obfuscation, to ensure data remains confidential both at rest and if the storage medium is compromised.
Real-world impact
Real-world CVEs caused by CWE-313
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Cleartext credentials in world-readable file.
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Password in cleartext in config file.
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Password in cleartext in config file.
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Decrypted copy of a message written to disk given a combination of options and when user replies to an encrypted message.
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Cleartext storage of private key and passphrase in log file when user imports the key.
How attackers exploit it
Step-by-step attacker path
- 1
The following examples show a portion of properties and configuration files for Java and ASP.NET applications. The files include username and password information but they are stored in cleartext.
- 2
This Java example shows a properties file with a cleartext username / password pair.
- 3
The following example shows a portion of a configuration file for an ASP.Net application. This configuration file includes username and password information for a connection to a database but the pair is stored in cleartext.
- 4
Username and password information should not be included in a configuration file or a properties file in cleartext as this will allow anyone who can read the file access to the resource. If possible, encrypt this information.
Vulnerable code example
Vulnerable Java
This Java example shows a properties file with a cleartext username / password pair.
```
# Java Web App ResourceBundle properties file*
...
webapp.ldap.username=secretUsername
webapp.ldap.password=secretPassword
... Secure code example
Secure pseudo
// Validate, sanitize, or use a safe API before reaching the sink.
function handleRequest(input) {
const safe = validateAndEscape(input);
return executeWithGuards(safe);
} What changed: the unsafe sink is replaced (or the input is validated/escaped) so the same payload no longer triggers the weakness.
Prevention checklist
How to prevent CWE-313
- Architecture Use safe-by-default frameworks and APIs that prevent the unsafe pattern from being expressible.
- Implementation Validate input at trust boundaries; use allowlists, not denylists.
- Implementation Apply the principle of least privilege to credentials, file paths, and runtime permissions.
- Testing Cover this weakness in CI: SAST rules + targeted unit tests for the data flow.
- Operation Monitor logs for the runtime signals listed in the next section.
Detection signals
How to detect CWE-313
CWE-313
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Frequently asked questions What is CWE-313?
How serious is CWE-313?
What languages or platforms are affected by CWE-313?
How can I prevent CWE-313?
How does Plexicus detect and fix CWE-313?
Where can I learn more about CWE-313?
Frequently asked questions
What is CWE-313?
This vulnerability occurs when an application writes sensitive data, such as passwords or personal information, directly to a file or disk without using encryption.
How serious is CWE-313?
MITRE has not published a likelihood-of-exploit rating for this weakness. Treat it as medium-impact until your threat model proves otherwise.
What languages or platforms are affected by CWE-313?
MITRE has not specified affected platforms for this CWE — it can apply across most application stacks.
How can I prevent CWE-313?
Use safe-by-default frameworks, validate untrusted input at trust boundaries, and apply the principle of least privilege. Cover the data-flow signature in CI with SAST.
How does Plexicus detect and fix CWE-313?
Plexicus's SAST engine matches the data-flow signature for CWE-313 on every commit. When a match is found, our Codex Remedium agent opens a fix PR with the corrected code, tests, and a one-line summary for the reviewer.
Where can I learn more about CWE-313?
MITRE publishes the canonical definition at https://cwe.mitre.org/data/definitions/313.html. You can also reference OWASP and NIST documentation for adjacent guidance.
Related weaknesses
Weaknesses related to CWE-313
CWE-312 Parent
Cleartext Storage of Sensitive Information
This vulnerability occurs when an application stores sensitive data like passwords, credit card numbers, or personal information in plain…
CWE-314 Sibling
Cleartext Storage in the Registry
This vulnerability occurs when an application saves sensitive data, like passwords or keys, as plain text in the Windows Registry.
CWE-315 Sibling
Cleartext Storage of Sensitive Information in a Cookie
This vulnerability occurs when an application directly stores sensitive data, like session tokens or personal details, in a browser cookie…
CWE-316 Sibling
Cleartext Storage of Sensitive Information in Memory
This vulnerability occurs when an application stores sensitive data, such as passwords or encryption keys, in memory without any form of…
CWE-317 Sibling
Cleartext Storage of Sensitive Information in GUI
This vulnerability occurs when an application stores sensitive data, such as passwords or personal information, in plain text within its…
CWE-318 Sibling
Cleartext Storage of Sensitive Information in Executable
This vulnerability occurs when an application embeds sensitive information, like passwords or keys, directly within its executable code…
CWE-526 Sibling
Cleartext Storage of Sensitive Information in an Environment Variable
This vulnerability occurs when an application stores sensitive data, such as passwords or API keys, as plain text in an environment…
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