If a user saved passwords before Firefox 58 and then later set a master password, an unencrypted copy of these passwords is still accessible. This is because the older stored password file was not deleted when the data was copied to a new format starting in Firefox 58. The new master password is added only on the new file. This could allow the exposure of stored password data outside of user expectations. External Reference: https://www.mozilla.org/en-US/security/advisories/mfsa2018-20/#CVE-2018-12383
Acknowledgments: Name: the Mozilla project Upstream: Jurgen Gaeremyn
More information including wontfix decision in the upstream ticket: https://bugzilla.mozilla.org/show_bug.cgi?id=1475775
Mitigation: To mitigate against this flaw, examine user profile directories for the presence of both `key3.db` and `key4.db` files. If both are present, `key3.db` should be deleted.
This issue has been addressed in the following products: Red Hat Enterprise Linux 6 Via RHSA-2018:2834 https://access.redhat.com/errata/RHSA-2018:2834
This issue has been addressed in the following products: Red Hat Enterprise Linux 7 Via RHSA-2018:2835 https://access.redhat.com/errata/RHSA-2018:2835
Statement: Upstream decided to not fix this issue in Firefox ESR 60.2 given the low impact. A future ESR update may correct this flaw. This flaw would impact users who had saved passwords from Firefox 58 or earlier that were not protected by a master password (resulting in an un-encrypted `key3.db`), but set a master password when using Firefox 59 or newer (resulting in an encrypted `key4.db`). The old key file was kept around to facilitate downgrading to Firefox 58. This flaw cannot be exploited through email in Thunderbird as scripting is disabled in this for email content. It may be possible to exploit through Feeds (Atom or RSS) or other browser-like contexts.
This issue has been addressed in the following products: Red Hat Enterprise Linux 6 Via RHSA-2018:3403 https://access.redhat.com/errata/RHSA-2018:3403
This issue has been addressed in the following products: Red Hat Enterprise Linux 7 Via RHSA-2018:3458 https://access.redhat.com/errata/RHSA-2018:3458