CWE-640 忘记口令恢复机制弱

Weak Password Recovery Mechanism for Forgotten Password

结构: Simple

Abstraction: Base

状态: Incomplete

被利用可能性: High

基本描述

The software contains a mechanism for users to recover or change their passwords without knowing the original password, but the mechanism is weak.

扩展描述

It is common for an application to have a mechanism that provides a means for a user to gain access to their account in the event they forget their password. Very often the password recovery mechanism is weak, which has the effect of making it more likely that it would be possible for a person other than the legitimate system user to gain access to that user's account. Weak password recovery schemes completely undermine a strong password authentication scheme.

This weakness may be that the security question is too easy to guess or find an answer to (e.g. because the question is too common, or the answers can be found using social media). Or there might be an implementation weakness in the password recovery mechanism code that may for instance trick the system into e-mailing the new password to an e-mail account other than that of the user. There might be no throttling done on the rate of password resets so that a legitimate user can be denied service by an attacker if an attacker tries to recover their password in a rapid succession. The system may send the original password to the user rather than generating a new temporary password. In summary, password recovery functionality, if not carefully designed and implemented can often become the system's weakest link that can be misused in a way that would allow an attacker to gain unauthorized access to the system.

相关缺陷

• cwe_Nature: ChildOf cwe_CWE_ID: 287 cwe_View_ID: 1000 cwe_Ordinal: Primary

• cwe_Nature: ChildOf cwe_CWE_ID: 287 cwe_View_ID: 1003 cwe_Ordinal: Primary

适用平台

Language: {'cwe_Class': 'Language-Independent', 'cwe_Prevalence': 'Undetermined'}

常见的影响

范围	影响	注释
Access Control	Gain Privileges or Assume Identity	An attacker could gain unauthorized access to the system by retrieving legitimate user's authentication credentials.
Availability	DoS: Resource Consumption (Other)	An attacker could deny service to legitimate system users by launching a brute force attack on the password recovery mechanism using user ids of legitimate users.
['Integrity', 'Other']	Other	The system's security functionality is turned against the system by the attacker.

可能的缓解方案

Architecture and Design

策略:

Make sure that all input supplied by the user to the password recovery mechanism is thoroughly filtered and validated.

Architecture and Design

策略:

Do not use standard weak security questions and use several security questions.

Architecture and Design

策略:

Make sure that there is throttling on the number of incorrect answers to a security question. Disable the password recovery functionality after a certain (small) number of incorrect guesses.

Architecture and Design

策略:

Require that the user properly answers the security question prior to resetting their password and sending the new password to the e-mail address of record.

Architecture and Design

策略:

Never allow the user to control what e-mail address the new password will be sent to in the password recovery mechanism.

Architecture and Design

策略:

Assign a new temporary password rather than revealing the original password.

示例代码

例

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.

Notes

Maintenance
This entry might be reclassified as a category or "loose composite," since it lists multiple specific errors that can make the mechanism weak. However, under view 1000, it could be a weakness under protection mechanism failure, although it is different from most PMF issues since it is related to a feature that is designed to bypass a protection mechanism (specifically, the lack of knowledge of a password).
Maintenance
This entry probably needs to be split; see extended description.

分类映射

映射的分类名	ImNode ID	Fit	Mapped Node Name
WASC	49		Insufficient Password Recovery

相关攻击模式

• CAPEC-50

引用

• REF-44 24 Deadly Sins of Software Security

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