CVE-2020-6824

Initially, a user opens a Private Browsing Window and generates a password for a site, then closes the Private Browsing Window but leaves Firefox open. Subsequently, if the user had opened a new Private Browsing Window, revisited the same site, and generated a new password - the generated passwords would have been identical, rather than independent. This vulnerability affects Firefox < 75.

Weakness

Authenticating a user, or otherwise establishing a new user session, without invalidating any existing session identifier gives an attacker the opportunity to steal authenticated sessions.

Affected Software

Extended Description

Such a scenario is commonly observed when:

In the generic exploit of session fixation vulnerabilities, an attacker creates a new session on a web application and records the associated session identifier. The attacker then causes the victim to associate, and possibly authenticate, against the server using that session identifier, giving the attacker access to the user’s account through the active session.

Potential Mitigations

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/196.html
• https://cwe.mitre.org/data/definitions/21.html
• https://cwe.mitre.org/data/definitions/31.html
• https://cwe.mitre.org/data/definitions/39.html
• https://cwe.mitre.org/data/definitions/59.html
• https://cwe.mitre.org/data/definitions/60.html
• https://cwe.mitre.org/data/definitions/61.html

References

• https://bugzilla.mozilla.org/show_bug.cgi?id=1621853
• https://www.mozilla.org/security/advisories/mfsa2020-12/
• https://bugzilla.mozilla.org/show_bug.cgi?id=1621853
• https://www.mozilla.org/security/advisories/mfsa2020-12/