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CAPEC-2: Inducing Account Lockout

Inducing Account Lockout
Definition in a New Window Definition in a New Window
Attack Pattern ID: 2
Abstraction: Standard
Status: Draft
Completeness: Complete
Presentation Filter:
+ Summary

An attacker leverages the security functionality of the system aimed at thwarting potential attacks to launch a denial of service attack against a legitimate system user. Many systems, for instance, implement a password throttling mechanism that locks an account after a certain number of incorrect log in attempts. An attacker can leverage this throttling mechanism to lock a legitimate user out of their own account. The weakness that is being leveraged by an attacker is the very security feature that has been put in place to counteract attacks.

+ Attack Steps
  1. Investigate account lockout behavior of system: Investigate the security features present in the system that may trigger an account lockout

    Analyze system documentation to find list of events that could potentially cause account lockout

    Obtain user account in system and attempt to lock it out by sending malformed or incorrect data repeatedly

    Determine another user's login ID, and attempt to brute force the password (or other credentials) for it a predetermined number of times, or until the system provides an indication that the account is locked out.

  2. Obtain list of user accounts to lock out: Generate a list of valid user accounts to lock out

    Obtain list of authorized users using another attack pattern, such as SQL Injection.

    Attempt to create accounts if possible; system should indicate if a user ID is already taken.

    Attempt to brute force user IDs if system reveals whether a given user ID is valid or not upon failed login attempts.

  1. Lock Out Accounts: Perform lockout procedure for all accounts that the attacker wants to lock out.

    For each user ID to be locked out, perform the lockout procedure discovered in the first step.

+ Attack Prerequisites
  • The system has a lockout mechanism.

  • An attacker must be able to reproduce behavior that would result in an account being locked.

+ Typical Severity


+ Typical Likelihood of Exploit

Likelihood: High

+ Methods of Attack
  • API Abuse
  • Flooding
  • Brute Force
+ Examples-Instances


A famous example of this type an attack 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.

+ Attacker Skills or Knowledge Required

Skill or Knowledge Level: Low

+ Resources Required

Computer with access to the login portion of the target system

+ Solutions and Mitigations

Implement intelligent password throttling mechanisms such as those which take IP address into account, in addition to the login name.

When implementing security features, consider how they can be misused and made to turn on themselves.

+ Attack Motivation-Consequences
ScopeTechnical ImpactNote
DoS: resource consumption (other)
Denial of Service
+ Content History
CAPEC Content TeamThe MITRE Corporation2014-06-23Internal_CAPEC_Team

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Page Last Updated or Reviewed: August 04, 2017