CWE-354: Improper Validation of Integrity Check Value

Definition

What is CWE-354?

This vulnerability occurs when software fails to properly check the integrity of data by validating its checksum or hash value. Without this verification, the application cannot reliably detect if information has been altered, corrupted, or tampered with during storage or transmission.

Ignoring checksum validation introduces a preventable security gap. Most protocols specify a standard algorithm for generating these integrity values. The developer's responsibility is to implement that same calculation and compare the result against the provided checksum—a straightforward process that acts as a critical first line of defense against data corruption and malicious manipulation. Failure to perform this match correctly can have severe consequences. Since the application trusts the data as authentic, it may process malicious instructions, load corrupted files, or make decisions based on falsified information. This simple oversight can escalate into system compromise, data loss, or unstable behavior, making proper checksum verification a fundamental requirement for secure data handling.

Real-world impact

Real-world CVEs caused by CWE-354

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

How attackers exploit it

Step-by-step attacker path

1
Identify a code path that handles untrusted input without validation.
2
Craft a payload that exercises the unsafe behavior — injection, traversal, overflow, or logic abuse.
3
Deliver the payload through a normal request and observe the application's reaction.
4
Iterate until the response leaks data, executes attacker code, or escalates privileges.

Vulnerable code example

Vulnerable C

The following example demonstrates the weakness.

Vulnerable C

sd = socket(AF_INET, SOCK_DGRAM, 0); serv.sin_family = AF_INET;
  serv.sin_addr.s_addr = htonl(INADDR_ANY);
  servr.sin_port = htons(1008);
  bind(sd, (struct sockaddr *) & serv, sizeof(serv));
  while (1) {
  		memset(msg, 0x0, MAX_MSG);
  		clilen = sizeof(cli);
  		if (inet_ntoa(cli.sin_addr)==...) n = recvfrom(sd, msg, MAX_MSG, 0, (struct sockaddr *) & cli, &clilen);
  }

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-354

Implementation Ensure that the checksums present in messages are properly checked in accordance with the protocol specification before they are parsed and used.

Detection signals

How to detect CWE-354

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.

CWE-354

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Frequently asked questions

What is CWE-354?

This vulnerability occurs when software fails to properly check the integrity of data by validating its checksum or hash value. Without this verification, the application cannot reliably detect if information has been altered, corrupted, or tampered with during storage or transmission.

How serious is CWE-354?

MITRE rates the likelihood of exploit as Medium — exploitation is realistic but typically requires specific conditions.

What languages or platforms are affected by CWE-354?

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

How can I prevent CWE-354?

Ensure that the checksums present in messages are properly checked in accordance with the protocol specification before they are parsed and used.

How does Plexicus detect and fix CWE-354?

Plexicus's SAST engine matches the data-flow signature for CWE-354 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-354?

MITRE publishes the canonical definition at https://cwe.mitre.org/data/definitions/354.html. You can also reference OWASP and NIST documentation for adjacent guidance.

Related weaknesses

Weaknesses related to CWE-354

CWE-345 Parent

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Improper Validation of Integrity Check Value

What is CWE-354?

Real-world CVEs caused by CWE-354

Step-by-step attacker path

Vulnerable C

Secure pseudo

How to prevent CWE-354

How to detect CWE-354

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

Frequently asked questions

Weaknesses related to CWE-354

Insufficient Verification of Data Authenticity

Missing Source Correlation of Multiple Independent Data

Origin Validation Error

Improper Verification of Cryptographic Signature

Use of Less Trusted Source

Acceptance of Extraneous Untrusted Data With Trusted Data

Insufficient Type Distinction

Cross-Site Request Forgery (CSRF)

Missing Support for Integrity Check

Further reading

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Sample evidence handover

Server-Side Request Forgery in `webhooks/receiver`