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Improper Restriction of Excessive Authentication Attempts

Draft Base
Structure: Simple
Description

This vulnerability occurs when an application fails to properly limit how many times someone can attempt to log in or verify their identity in rapid succession, allowing attackers to systematically guess credentials.

This vulnerability occurs when an application fails to properly limit how many times someone can attempt to log in or verify their identity in rapid succession, allowing attackers to systematically guess credentials.
Extended Description

Without controls like account lockouts, rate limiting, or increasing time delays after failures, automated tools can make thousands of login attempts per minute. This makes brute-force and credential stuffing attacks highly effective, as attackers can try common passwords or leaked credentials until they succeed. Implementing these restrictions is a fundamental security control for any authentication system. Detecting and enforcing consistent authentication policies across all your services and APIs can be challenging. While SAST and DAST tools can identify missing protections, an ASPM like Plexicus helps by continuously monitoring your entire application stack for these misconfigurations and using AI to generate specific remediation guidance, streamlining the fix process.
Common Consequences 1
Scope: Access Control

Impact: Bypass Protection Mechanism

An attacker could perform an arbitrary number of authentication attempts using different passwords, and eventually gain access to the targeted account using a brute force attack.
Detection Methods 6
Dynamic Analysis with Automated Results InterpretationHigh
According to SOAR [REF-1479], the following detection techniques may be useful: ``` Highly cost effective: ``` Web Application Scanner Web Services Scanner Database Scanners ``` Cost effective for partial coverage: ``` Host-based Vulnerability Scanners - Examine configuration for flaws, verifying that audit mechanisms work, ensure host configuration meets certain predefined criteria
Dynamic Analysis with Manual Results InterpretationHigh
According to SOAR [REF-1479], the following detection techniques may be useful: ``` Highly cost effective: ``` Fuzz Tester Framework-based Fuzzer ``` Cost effective for partial coverage: ``` Forced Path Execution
Manual Static Analysis - Source CodeHigh
According to SOAR [REF-1479], the following detection techniques may be useful: ``` Highly cost effective: ``` Focused Manual Spotcheck - Focused manual analysis of source Manual Source Code Review (not inspections)
Automated Static Analysis - Source CodeSOAR Partial
According to SOAR [REF-1479], the following detection techniques may be useful: ``` Cost effective for partial coverage: ``` Source code Weakness Analyzer Context-configured Source Code Weakness Analyzer
Automated Static AnalysisSOAR Partial
According to SOAR [REF-1479], the following detection techniques may be useful: ``` Cost effective for partial coverage: ``` Configuration Checker
Architecture or Design ReviewHigh
According to SOAR [REF-1479], the following detection techniques may be useful: ``` Highly cost effective: ``` Formal Methods / Correct-By-Construction ``` Cost effective for partial coverage: ``` Inspection (IEEE 1028 standard) (can apply to requirements, design, source code, etc.)
Potential Mitigations 2
Phase: Architecture and Design
Common protection mechanisms include: - Disconnecting the user after a small number of failed attempts - Implementing a timeout - Locking out a targeted account - Requiring a computational task on the user's part.
Phase: Architecture and Design

Strategy: Libraries or Frameworks

Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid [REF-1482]. Consider using libraries with authentication capabilities such as OpenSSL or the ESAPI Authenticator. [REF-45]
Demonstrative Examples 5

ID : DX-117

In January 2009, an attacker was able to gain administrator access to a Twitter server because the server did not restrict the number of login attempts [REF-236]. The attacker targeted a member of Twitter's support team and was able to successfully guess the member's password using a brute force attack by guessing a large number of common words. After gaining access as the member of the support staff, the attacker used the administrator panel to gain access to 33 accounts that belonged to celebrities and politicians. Ultimately, fake Twitter messages were sent that appeared to come from the compromised accounts.
The following code, extracted from a servlet's doPost() method, performs an authentication lookup every time the servlet is invoked.

Code Example:

Bad
Java
java
However, the software makes no attempt to restrict excessive authentication attempts.
This code attempts to limit the number of login attempts by causing the process to sleep before completing the authentication.

Code Example:

Bad
PHP
php
However, there is no limit on parallel connections, so this does not increase the amount of time an attacker needs to complete an attack.
In the following C/C++ example the validateUser method opens a socket connection, reads a username and password from the socket and attempts to authenticate the username and password.

Code Example:

Bad
C
c
The validateUser method will continuously check for a valid username and password without any restriction on the number of authentication attempts made. The method should limit the number of authentication attempts made to prevent brute force attacks as in the following example code.

Code Example:

Good
C
c
Consider this example from a real-world attack against the iPhone [REF-1218]. An attacker can use brute force methods; each time there is a failed guess, the attacker quickly cuts the power before the failed entry is recorded, effectively bypassing the intended limit on the number of failed authentication attempts. Note that this attack requires removal of the cell phone battery and connecting directly to the phone's power source, and the brute force attack is still time-consuming.
Observed Examples 7
CVE-2019-0039the REST API for a network OS has a high limit for number of connections, allowing brute force password guessing
CVE-1999-1152Product does not disconnect or timeout after multiple failed logins.
CVE-2001-1291Product does not disconnect or timeout after multiple failed logins.
CVE-2001-0395Product does not disconnect or timeout after multiple failed logins.
CVE-2001-1339Product does not disconnect or timeout after multiple failed logins.
CVE-2002-0628Product does not disconnect or timeout after multiple failed logins.
CVE-1999-1324User accounts not disabled when they exceed a threshold; possibly a resultant problem.
References 3
OWASP Enterprise Security API (ESAPI) Project
OWASP
https://owasp.org/www-project-enterprise-security-api/(2025-07-24)
ID: REF-45
Weak Password Brings 'Happiness' to Twitter Hacker
Kim Zetter
09-01-2009
https://www.wired.com/2009/01/professed-twitt/(2023-04-07)
ID: REF-236
This Black Box Can Brute Force Crack iPhone PIN Passcodes
Graham Cluley
The Mac Security Blog
16-03-2015
https://www.intego.com/mac-security-blog/iphone-pin-pass-code/
ID: REF-1218
Applicable Platforms
Languages:
Not Language-Specific : Undetermined
Modes of Introduction
Architecture and Design
Related Attack Patterns
Related Weaknesses
ChildOf: Weak Authentication (CWE-1390)
ChildOf: Improper Authentication (CWE-287)
ChildOf: Improper Control of Interaction Frequency (CWE-799)
Taxonomy Mapping
  • PLOVER
  • Software Fault Patterns