CWE-530 Variant Incomplete

Exposure of Backup File to an Unauthorized Control Sphere

This vulnerability occurs when backup or temporary files are stored in locations that unauthorized users can access, such as web directories.

Definition

What is CWE-530?

This vulnerability occurs when backup or temporary files are stored in locations that unauthorized users can access, such as web directories.
Developers and systems often create backup copies of live files, sometimes automatically renaming them with extensions like .bak, .old, or .~bk. When these files are left within a publicly accessible directory—like a web server's root—attackers can directly request and download them. This exposes source code, configuration files, or sensitive data that should remain protected. Manually finding and securing every misplaced backup file across a complex application is error-prone. An ASPM platform like Plexicus can automatically detect these exposed files across your entire stack, using SAST and DAST techniques to identify the risk. Furthermore, Plexicus's AI-driven remediation can provide specific guidance on moving or deleting these files, helping you close the gap quickly and consistently.
Real-world impact

Real-world CVEs caused by CWE-530

No public CVE references are linked to this CWE in MITRE's catalog yet.

How attackers exploit it

Step-by-step attacker path

  1. 1

    Identify a code path that handles untrusted input without validation.

  2. 2

    Craft a payload that exercises the unsafe behavior — injection, traversal, overflow, or logic abuse.

  3. 3

    Deliver the payload through a normal request and observe the application's reaction.

  4. 4

    Iterate until the response leaks data, executes attacker code, or escalates privileges.

Vulnerable code example

Vulnerable pseudo

MITRE has not published a code example for this CWE. The pattern below is illustrative — see Resources for canonical references.

Vulnerable pseudo 
// Example pattern — see MITRE for the canonical references.
function handleRequest(input) {
  // Untrusted input flows directly into the sensitive sink.
  return executeUnsafe(input);
}
Secure code example

Secure pseudo

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-530

  • Policy Recommendations include implementing a security policy within your organization that prohibits backing up web application source code in the webroot.
Detection signals

How to detect CWE-530

Automated Static Analysis High

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.)

Plexicus auto-fix

Plexicus auto-detects CWE-530 and opens a fix PR in under 60 seconds.

Codex Remedium scans every commit, identifies this exact weakness, and ships a reviewer-ready pull request with the patch. No tickets. No hand-offs.

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Frequently asked questions

Frequently asked questions

What is CWE-530?

This vulnerability occurs when backup or temporary files are stored in locations that unauthorized users can access, such as web directories.

How serious is CWE-530?

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-530?

MITRE has not specified affected platforms for this CWE — it can apply across most application stacks.

How can I prevent CWE-530?

Recommendations include implementing a security policy within your organization that prohibits backing up web application source code in the webroot.

How does Plexicus detect and fix CWE-530?

Plexicus's SAST engine matches the data-flow signature for CWE-530 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-530?

MITRE publishes the canonical definition at https://cwe.mitre.org/data/definitions/530.html. You can also reference OWASP and NIST documentation for adjacent guidance.

Related weaknesses

Weaknesses related to CWE-530

CWE-552 Parent

Files or Directories Accessible to External Parties

This vulnerability occurs when an application exposes files or directories to users who shouldn't have access to them.

CWE-219 Sibling

Storage of File with Sensitive Data Under Web Root

This vulnerability occurs when an application saves sensitive files, such as configuration data or private keys, inside the web server's…

CWE-220 Sibling

Storage of File With Sensitive Data Under FTP Root

This vulnerability occurs when an application saves sensitive files, such as configuration or user data, within the directory served by an…

CWE-527 Sibling

Exposure of Version-Control Repository to an Unauthorized Control Sphere

This vulnerability occurs when a version control repository, like Git or SVN, is accidentally placed in a location accessible to…

CWE-528 Sibling

Exposure of Core Dump File to an Unauthorized Control Sphere

This vulnerability occurs when an application creates a core dump file (a snapshot of memory at the time of a crash) and places it in a…

CWE-529 Sibling

Exposure of Access Control List Files to an Unauthorized Control Sphere

This vulnerability occurs when an application stores sensitive access control list (ACL) files in a location that is accessible to…

CWE-539 Sibling

Use of Persistent Cookies Containing Sensitive Information

This vulnerability occurs when a web application stores sensitive data, like authentication details or personal information, within…

CWE-553 Sibling

Command Shell in Externally Accessible Directory

This vulnerability occurs when a command shell script is placed in a web-accessible directory, such as /cgi-bin/. Attackers can directly…

Resources

Further reading

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