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User passwords are stored in clear text in the Django session

Moderate severity GitHub Reviewed Published Jul 8, 2020 in jazzband/django-two-factor-auth • Updated Sep 16, 2024

Package

pip django-two-factor-auth (pip)

Affected versions

< 1.12

Patched versions

1.12

Description

Impact

django-two-factor-auth versions 1.11 and before store the user's password in clear text in the user session (base64-encoded). The password is stored in the session when the user submits their username and password, and is removed once they complete authentication by entering a two-factor authentication code. This means that the password is stored in clear text in the session for an arbitrary amount of time, and potentially forever if the user begins the login process by entering their username and password, and then leaves before entering their two-factor authentication code.

The severity of this issue depends on which type of session storage you have configured: in the worst case, if you're using Django's default database session storage, then users' password are stored in clear text in your database. In the best case, if you're using Django's signed cookie session, then users' passwords are only stored in clear text within their browser's cookie store. In the common case of using Django's cache session store, the users' password are stored in clear text in whatever cache storage you have configured (typically Memcached or Redis).

Patches

Upgrade to version 1.12 to resolve this issue.

After upgrading, users should be sure to delete any clear text passwords that have been stored. For example, if you're using the database session backend, you'll likely want to delete any session record from the database and purge that data from any database backups or replicas.

In addition, affected organizations who have suffered a database breach while using an affected version should inform their users that their clear text passwords have been compromised. All organizations should encourage users whose passwords were insecurely stored to change these passwords on any sites where they were used.

Workarounds

Switching Django's session storage to use signed cookies instead of the database or cache lessens the impact of this issue, but should not be done without a thorough understanding of the security tradeoffs of using signed cookies rather than a server-side session storage. There is no way to fully mitigate the issue without upgrading.

References

For an explanation of why storing cleartext password is a substantial vulnerability: Hashing Passwords: One-Way Road to Security.
For documentation on configuring the Django session storage engine: Django session documentation.

For more information

If you have any questions or comments about this advisory:

References

@Bouke Bouke published to jazzband/django-two-factor-auth Jul 8, 2020
Reviewed Jul 10, 2020
Published to the GitHub Advisory Database Jul 10, 2020
Last updated Sep 16, 2024

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v4 base metrics

Exploitability Metrics
Attack Vector Network
Attack Complexity Low
Attack Requirements Present
Privileges Required Low
User interaction None
Vulnerable System Impact Metrics
Confidentiality High
Integrity Low
Availability None
Subsequent System Impact Metrics
Confidentiality None
Integrity None
Availability None

CVSS v4 base metrics

Exploitability Metrics
Attack Vector: This metric reflects the context by which vulnerability exploitation is possible. This metric value (and consequently the resulting severity) will be larger the more remote (logically, and physically) an attacker can be in order to exploit the vulnerable system. The assumption is that the number of potential attackers for a vulnerability that could be exploited from across a network is larger than the number of potential attackers that could exploit a vulnerability requiring physical access to a device, and therefore warrants a greater severity.
Attack Complexity: This metric captures measurable actions that must be taken by the attacker to actively evade or circumvent existing built-in security-enhancing conditions in order to obtain a working exploit. These are conditions whose primary purpose is to increase security and/or increase exploit engineering complexity. A vulnerability exploitable without a target-specific variable has a lower complexity than a vulnerability that would require non-trivial customization. This metric is meant to capture security mechanisms utilized by the vulnerable system.
Attack Requirements: This metric captures the prerequisite deployment and execution conditions or variables of the vulnerable system that enable the attack. These differ from security-enhancing techniques/technologies (ref Attack Complexity) as the primary purpose of these conditions is not to explicitly mitigate attacks, but rather, emerge naturally as a consequence of the deployment and execution of the vulnerable system.
Privileges Required: This metric describes the level of privileges an attacker must possess prior to successfully exploiting the vulnerability. The method by which the attacker obtains privileged credentials prior to the attack (e.g., free trial accounts), is outside the scope of this metric. Generally, self-service provisioned accounts do not constitute a privilege requirement if the attacker can grant themselves privileges as part of the attack.
User interaction: This metric captures the requirement for a human user, other than the attacker, to participate in the successful compromise of the vulnerable system. This metric determines whether the vulnerability can be exploited solely at the will of the attacker, or whether a separate user (or user-initiated process) must participate in some manner.
Vulnerable System Impact Metrics
Confidentiality: This metric measures the impact to the confidentiality of the information managed by the VULNERABLE SYSTEM due to a successfully exploited vulnerability. Confidentiality refers to limiting information access and disclosure to only authorized users, as well as preventing access by, or disclosure to, unauthorized ones.
Integrity: This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information. Integrity of the VULNERABLE SYSTEM is impacted when an attacker makes unauthorized modification of system data. Integrity is also impacted when a system user can repudiate critical actions taken in the context of the system (e.g. due to insufficient logging).
Availability: This metric measures the impact to the availability of the VULNERABLE SYSTEM resulting from a successfully exploited vulnerability. While the Confidentiality and Integrity impact metrics apply to the loss of confidentiality or integrity of data (e.g., information, files) used by the system, this metric refers to the loss of availability of the impacted system itself, such as a networked service (e.g., web, database, email). Since availability refers to the accessibility of information resources, attacks that consume network bandwidth, processor cycles, or disk space all impact the availability of a system.
Subsequent System Impact Metrics
Confidentiality: This metric measures the impact to the confidentiality of the information managed by the SUBSEQUENT SYSTEM due to a successfully exploited vulnerability. Confidentiality refers to limiting information access and disclosure to only authorized users, as well as preventing access by, or disclosure to, unauthorized ones.
Integrity: This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information. Integrity of the SUBSEQUENT SYSTEM is impacted when an attacker makes unauthorized modification of system data. Integrity is also impacted when a system user can repudiate critical actions taken in the context of the system (e.g. due to insufficient logging).
Availability: This metric measures the impact to the availability of the SUBSEQUENT SYSTEM resulting from a successfully exploited vulnerability. While the Confidentiality and Integrity impact metrics apply to the loss of confidentiality or integrity of data (e.g., information, files) used by the system, this metric refers to the loss of availability of the impacted system itself, such as a networked service (e.g., web, database, email). Since availability refers to the accessibility of information resources, attacks that consume network bandwidth, processor cycles, or disk space all impact the availability of a system.
CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N

EPSS score

0.100%
(42nd percentile)

Weaknesses

CVE ID

CVE-2020-15105

GHSA ID

GHSA-vhr6-pvjm-9qwf

Source code

Credits

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