CWE-515 Base Incomplete High likelihood

Covert Storage Channel

A covert storage channel is a type of security flaw where one process secretly encodes data into a shared system resource (like a file, memory bit, or status flag), and another unauthorized process…

Definition

What is CWE-515?

A covert storage channel is a type of security flaw where one process secretly encodes data into a shared system resource (like a file, memory bit, or status flag), and another unauthorized process later reads that resource to extract the hidden information.
This vulnerability exploits the normal reuse of system memory or resources to create a hidden communication path. Instead of using a dedicated data channel, an attacker manipulates observable system properties—such as file names, registry values, or even the presence of temporary files—to store and transmit encoded messages. This turns everyday operations into a secret data pipeline that bypasses standard security controls. In practice, covert storage channels are a form of information leakage often linked to steganography or side-channel attacks. For example, a process with high privileges might write a user's password into a log file field meant only for timestamps, and a less-privileged process could then read that file. Developers must be aware that any system state readable by multiple actors can be misused in this way, requiring careful design to isolate sensitive data and audit all shared resource interactions.
Real-world impact

Real-world CVEs caused by CWE-515

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-515

  • Implementation Ensure that all reserved fields are set to zero before messages are sent and that no unnecessary information is included.
Detection signals

How to detect CWE-515

SAST High

Run static analysis (SAST) on the codebase looking for the unsafe pattern in the data flow.

DAST Moderate

Run dynamic application security testing against the live endpoint.

Runtime Moderate

Watch runtime logs for unusual exception traces, malformed input, or authorization bypass attempts.

Code review Moderate

Code review: flag any new code that handles input from this surface without using the validated framework helpers.

Plexicus auto-fix

Plexicus auto-detects CWE-515 and opens a fix PR in under 60 seconds.

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Frequently asked questions

Frequently asked questions

What is CWE-515?

A covert storage channel is a type of security flaw where one process secretly encodes data into a shared system resource (like a file, memory bit, or status flag), and another unauthorized process later reads that resource to extract the hidden information.

How serious is CWE-515?

MITRE rates the likelihood of exploit as High — this weakness is actively exploited in the wild and should be prioritized for remediation.

What languages or platforms are affected by CWE-515?

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

How can I prevent CWE-515?

Ensure that all reserved fields are set to zero before messages are sent and that no unnecessary information is included.

How does Plexicus detect and fix CWE-515?

Plexicus's SAST engine matches the data-flow signature for CWE-515 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-515?

MITRE publishes the canonical definition at https://cwe.mitre.org/data/definitions/515.html. You can also reference OWASP and NIST documentation for adjacent guidance.

Related weaknesses

Weaknesses related to CWE-515

CWE-514 Parent

Covert Channel

A covert channel is a hidden communication path that allows data to be transmitted in a way that bypasses the system's intended security…

CWE-385 Sibling

Covert Timing Channel

A covert timing channel is a security flaw where an attacker can deduce secret information by observing how long certain operations take…

Resources

Further reading

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