CWE - CWE-645: Overly Restrictive Account Lockout Mechanism (4.20) Common Weakness Enumeration A community-developed list of SW & HW weaknesses that can become vulnerabilities Home > CWE List > CWE-645: Overly Restrictive Account Lockout Mechanism (4.20) ID Lookup: * Home * About ▼ Who We Are User Stories History Documents Videos * Learn ▼ Basics Root Cause Mapping ► Guidance Quick Tips Examples How to Contribute Weakness Content FAQs Glossary * Access Content ▼ Top-N Lists ► Top 25 Software Top Hardware Top 10 KEV Weaknesses CWE List ► Current Version Reports Visualizations Releases Archive Downloads REST API * Community ▼ News ► Current News Blog Podcast News Archive CWE Board Working Groups & Special Interest Groups Email Lists * Search ▼ Search CWE List Search Website CWE Glossary Definition CWE-645: Overly Restrictive Account Lockout Mechanism Weakness ID: 645 Vulnerability Mapping : ALLOWED This CWE ID may be used to map to real-world vulnerabilities Abstraction: Base Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource. View customized information: Conceptual For users who are interested in more notional aspects of a weakness. Example: educators, technical writers, and project/program managers. Operational For users who are concerned with the practical application and details about the nature of a weakness and how to prevent it from happening. Example: tool developers, security researchers, pen-testers, incident response analysts. Mapping Friendly For users who are mapping an issue to CWE/CAPEC IDs, i.e., finding the most appropriate CWE for a specific issue (e.g., a CVE record). Example: tool developers, security researchers. Complete For users who wish to see all available information for the CWE/CAPEC entry. Custom For users who want to customize what details are displayed. Edit Custom Filter Conceptual Operational Mapping Friendly Select All Reset Clear Submit Cancel Description The product contains an account lockout protection mechanism, but the mechanism is too restrictive and can be triggered too easily, which allows attackers to deny service to legitimate users by causing their accounts to be locked out. Extended Description Account lockout is a security feature often present in applications as a countermeasure to the brute force attack on the password based authentication mechanism of the system. After a certain number of failed login attempts, the users' account may be disabled for a certain period of time or until it is unlocked by an administrator. Other security events may also possibly trigger account lockout. However, an attacker may use this very security feature to deny service to legitimate system users. It is therefore important to ensure that the account lockout security mechanism is not overly restrictive. Common Consequences This table specifies different individual consequences associated with the weakness. The Scope identifies the application security area that is violated, while the Impact describes the negative technical impact that arises if an adversary succeeds in exploiting this weakness. The Likelihood provides information about how likely the specific consequence is expected to be seen relative to the other consequences in the list. For example, there may be high likelihood that a weakness will be exploited to achieve a certain impact, but a low likelihood that it will be exploited to achieve a different impact. Impact Details DoS: Resource Consumption (Other) Scope: Availability Users could be locked out of accounts. Potential Mitigations Phase(s) Mitigation Architecture and Design Implement more intelligent password throttling mechanisms such as those which take IP address into account, in addition to the login name. Architecture and Design Implement a lockout timeout that grows as the number of incorrect login attempts goes up, eventually resulting in a complete lockout. Architecture and Design Consider alternatives to account lockout that would still be effective against password brute force attacks, such as presenting the user machine with a puzzle to solve (makes it do some computation). Relationships This table shows the weaknesses and high level categories that are related to this weakness. These relationships are defined as ChildOf, ParentOf, MemberOf and give insight to similar items that may exist at higher and lower levels of abstraction. In addition, relationships such as PeerOf and CanAlsoBe are defined to show similar weaknesses that the user may want to explore. Relevant to the view "Research Concepts" (View-1000) Nature Type ID Name ChildOf Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource. 287 Improper Authentication Relevant to the view "Software Development" (View-699) Nature Type ID Name MemberOf Category - a CWE entry that contains a set of other entries that share a common characteristic. 1211 Authentication Errors MemberOf Category - a CWE entry that contains a set of other entries that share a common characteristic. 1216 Lockout Mechanism Errors Relevant to the view "Architectural Concepts" (View-1008) Nature Type ID Name MemberOf Category - a CWE entry that contains a set of other entries that share a common characteristic. 1017 Lock Computer Modes Of Introduction The different Modes of Introduction provide information about how and when this weakness may be introduced. The Phase identifies a point in the life cycle at which introduction may occur, while the Note provides a typical scenario related to introduction during the given phase. Phase Note Architecture and Design COMMISSION: This weakness refers to an incorrect design related to an architectural security tactic. Applicable Platforms This listing shows possible areas for which the given weakness could appear. These may be for specific named Languages, Operating Systems, Architectures, Paradigms, Technologies, or a class of such platforms. The platform is listed along with how frequently the given weakness appears for that instance. Languages Class: Not Language-Specific (Undetermined Prevalence) Likelihood Of Exploit High Demonstrative Examples Example 1 A famous example of this type of weakness being exploited is the eBay attack. eBay always displays the user id of the highest bidder. In the final minutes of the auction, one of the bidders could try to log in as the highest bidder three times. After three incorrect log in attempts, eBay password throttling would kick in and lock out the highest bidder's account for some time. An attacker could then make their own bid and their victim would not have a chance to place the counter bid because they would be locked out. Thus an attacker could win the auction. Weakness Ordinalities Ordinality Description Primary (where the weakness exists independent of other weaknesses) Memberships This MemberOf Relationships table shows additional CWE Categories and Views that reference this weakness as a member. This information is often useful in understanding where a weakness fits within the context of external information sources. Nature Type ID Name MemberOf Category - a CWE entry that contains a set of other entries that share a common characteristic. 951 SFP Secondary Cluster: Insecure Authentication Policy MemberOf Category - a CWE entry that contains a set of other entries that share a common characteristic. 1396 Comprehensive Categorization: Access Control Vulnerability Mapping Notes Usage ALLOWED (this CWE ID may be used to map to real-world vulnerabilities) Reason Acceptable-Use Rationale This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities. Comments Carefully read both the name and description to ensure that this mapping is an appropriate fit. Do not try to 'force' a mapping to a lower-level Base/Variant simply to comply with this preferred level of abstraction. Related Attack Patterns CAPEC-ID Attack Pattern Name CAPEC-2 Inducing Account Lockout Content History Submissions Submission Date Submitter Organization 2008-01-30 (CWE Draft 8, 2008-01-30) Evgeny Lebanidze Cigital Modifications Modification Date Modifier Organization 2025-12-11 (CWE 4.19, 2025-12-11) CWE Content Team MITRE updated Weakness_Ordinalities 2023-06-29 (CWE 4.12, 2023-06-29) CWE Content Team MITRE updated Mapping_Notes 2023-04-27 (CWE 4.11, 2023-04-27) CWE Content Team MITRE updated Relationships 2023-01-31 (CWE 4.10, 2023-01-31) CWE Content Team MITRE updated Description 2020-02-24 (CWE 4.0, 2020-02-24) CWE Content Team MITRE updated Relationships 2019-06-20 (CWE 3.3, 2019-06-20) CWE Content Team MITRE updated Related_Attack_Patterns 2017-11-08 (CWE 3.0, 2017-11-08) CWE Content Team MITRE updated Applicable_Platforms, Demonstrative_Examples, Description, Enabling_Factors_for_Exploitation, Modes_of_Introduction, Observed_Examples, Relationships 2014-07-30 (CWE 2.8, 2014-07-31) CWE Content Team MITRE updated Relationships 2012-10-30 (CWE 2.3, 2012-10-30) CWE Content Team MITRE updated Potential_Mitigations 2012-05-11 (CWE 2.2, 2012-05-15) CWE Content Team MITRE updated Relationships 2011-06-01 (CWE 1.13, 2011-06-01) CWE Content Team MITRE updated Common_Consequences 2008-10-14 (CWE 1.0.1, 2008-10-14) CWE Content Team MITRE updated Description 2008-09-08 (CWE 1.0, 2008-09-09) CWE Content Team MITRE updated Common_Consequences, Enabling_Factors_for_Exploitation, Relationships More information is available -- Please edit the custom filter or select a different filter. 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