Omission of Security-relevant Information

The product does not record or display information that would be important for identifying the source or nature of an attack, or determining if an action is safe.


The following examples help to illustrate the nature of this weakness and describe methods or techniques which can be used to mitigate the risk.

Note that the examples here are by no means exhaustive and any given weakness may have many subtle varieties, each of which may require different detection methods or runtime controls.

Example One

This code logs suspicious multiple login attempts.

function login($userName,$password){

    return True;
    if(recentLoginAttempts($userName) > 5){
      writeLog("Failed login attempt by User: " . $userName . " at " + date('r') );


This code only logs failed login attempts when a certain limit is reached. If an attacker knows this limit, they can stop their attack from being discovered by avoiding the limit.

Example Two

This code prints the contents of a file if a user has permission.

function readFile($filename){

  $user = getCurrentUser();
  $realFile = $filename;

  //resolve file if its a symbolic link
    $realFile = readlink($filename);

  if(fileowner($realFile) == $user){
    echo file_get_contents($realFile);
    echo 'Access denied';
    writeLog($user . ' attempted to access the file '. $filename . ' on '. date('r'));


While the code logs a bad access attempt, it logs the user supplied name for the file, not the canonicalized file name. An attacker can obscure their target by giving the script the name of a link to the file they are attempting to access. Also note this code contains a race condition between the is_link() and readlink() functions (CWE-363).

See Also

Comprehensive Categorization: Protection Mechanism Failure

Weaknesses in this category are related to protection mechanism failure.

OWASP Top Ten 2021 Category A09:2021 - Security Logging and Monitoring Failures

Weaknesses in this category are related to the A09 category "Security Logging and Monitoring Failures" in the OWASP Top Ten 2021.

Audit / Logging Errors

Weaknesses in this category are related to audit-based components of a software system. Frequently these deal with logging user activities in order to identify undesir...

Comprehensive CWE Dictionary

This view (slice) covers all the elements in CWE.

CWE Cross-section

This view contains a selection of weaknesses that represent the variety of weaknesses that are captured in CWE, at a level of abstraction that is likely to be useful t...

Weaknesses Introduced During Implementation

This view (slice) lists weaknesses that can be introduced during implementation.

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