CWE-552 Base Draft

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.

Definition

What is CWE-552?

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

This commonly happens in web servers, FTP servers, or similar systems where files are stored under a publicly accessible root directory. If the application doesn't implement proper access controls, sensitive files placed in or under this directory can be requested and retrieved by unauthorized users. The same risk applies when applications package files into archives (like ZIP or tar files) without first filtering out confidential documents from the included directories. In modern cloud and container environments, this flaw often appears as misconfigured storage buckets or file shares that are open to public or anonymous access. Managing this at scale is difficult; an ASPM like Plexicus can help you track and remediate these configuration flaws across your entire stack, from code to cloud.

Real-world impact

Real-world CVEs caused by CWE-552

CVE-2005-1835

Data file under web root.

How attackers exploit it

Step-by-step attacker path

1
The following Azure command updates the settings for a storage account:
2
However, "Allow Blob Public Access" is set to true, meaning that anonymous/public users can access blobs.
3
The command could be modified to disable "Allow Blob Public Access" by setting it to false.
4
The following Google Cloud Storage command gets the settings for a storage account named 'BUCKET_NAME':
5
Suppose the command returns the following result:

Vulnerable code example

Vulnerable Shell

The following Azure command updates the settings for a storage account:

Vulnerable Shell

az storage account update --name <storage-account> --resource-group <resource-group> --allow-blob-public-access true

Secure code example

Secure Shell

The command could be modified to disable "Allow Blob Public Access" by setting it to false.

Secure Shell

az storage account update --name <storage-account> --resource-group <resource-group> --allow-blob-public-access false

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-552

Implementation / System Configuration / Operation When storing data in the cloud (e.g., S3 buckets, Azure blobs, Google Cloud Storage, etc.), use the provider's controls to disable public access.

Detection signals

How to detect CWE-552

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.)

CWE-552

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Frequently asked questions

What is CWE-552?

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

How serious is CWE-552?

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-552?

MITRE lists the following affected platforms: Not Technology-Specific, Cloud Computing.

How can I prevent CWE-552?

When storing data in the cloud (e.g., S3 buckets, Azure blobs, Google Cloud Storage, etc.), use the provider's controls to disable public access.

How does Plexicus detect and fix CWE-552?

Plexicus's SAST engine matches the data-flow signature for CWE-552 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-552?

MITRE publishes the canonical definition at https://cwe.mitre.org/data/definitions/552.html. You can also reference OWASP and NIST documentation for adjacent guidance.

Related weaknesses

Weaknesses related to CWE-552

CWE-668 Parent

Files or Directories Accessible to External Parties

What is CWE-552?

Real-world CVEs caused by CWE-552

Step-by-step attacker path

Vulnerable Shell

Secure Shell

How to prevent CWE-552

How to detect CWE-552

Don't catalog this weakness. Prove it's reachable.

Frequently asked questions

Weaknesses related to CWE-552

Exposure of Resource to Wrong Sphere

Improper Isolation of Shared Resources on System-on-a-Chip (SoC)

Assumed-Immutable Data is Stored in Writable Memory

Binding to an Unrestricted IP Address

Improper Isolation of Shared Resources in Network On Chip (NoC)

Use of Externally-Controlled Format String

Exposure of Sensitive Information to an Unauthorized Actor

Passing Mutable Objects to an Untrusted Method

Returning a Mutable Object to an Untrusted Caller

Further reading

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Sample evidence handover

Server-Side Request Forgery in `webhooks/receiver`