GHSA-8wr4-2wm6-w3pr

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GHSA-8wr4-2wm6-w3pr

Summary: B2 Command Line Tool TOCTOU application key disclosure

Details: ### Impact Linux and Mac releases of the B2 command-line tool version 3.2.0 and below contain a key disclosure vulnerability that, in certain conditions, can be exploited by local attackers through a time-of-check-time-of-use (TOCTOU) race condition. The command line tool saves API keys (and bucket name-to-id mapping) in a local database file (`$XDG_CONFIG_HOME/b2/account_info`, `~/.b2_account_info` or a user-defined path) when `b2 authorize-account` is first run. This happens regardless of whether a valid key is provided or not. When first created, the file is world readable and is (typically a few milliseconds) later altered to be private to the user. If the directory is readable by a local attacker and the user did not yet run `b2 authorize-account` then during the brief period between file creation and permission modification, a local attacker can race to open the file and maintain a handle to it. This allows the local attacker to read the contents after the file after the sensitive information has been saved to it. ### Remediation Users that have not yet run `b2 authorize-account` should upgrade to B2 Command-Line Tool v3.2.1 before running it. Users that have run `b2 authorize-account` are safe if at the time of the file creation no other local users had read access to the local configuration file. Users that have run `b2 authorize-account` where the designated path could be opened by another local user should upgrade to B2 Command-Line Tool v3.2.1 and remove the database and regenerate all application keys. Note that `b2 clear-account` does not remove the database file and it should not be used to ensure that all open handles to the file are invalidated. ### Workarounds If B2 Command-Line Tool cannot be upgraded to v3.2.1 due to a dependency conflict, a binary release can be used instead. Alternatively a new version could be installed within a virtualenv, or the permissions can be changed to prevent local users from opening the database file. ### For more information If you have any questions or comments about this advisory: * Open an issue in [B2 Command-Line Tool](https://github.com/Backblaze/B2_Command_Line_Tool) mentioning the CVE id in the issue title * Email us at [[email protected]](mailto:[email protected])

References: https://github.com/Backblaze/B2_Command_Line_Tool/security/advisories/GHSA-8wr4-2wm6-w3pr, https://nvd.nist.gov/vuln/detail/CVE-2022-23653, https://github.com/Backblaze/B2_Command_Line_Tool/commit/c74029f9f75065e8f7e3c3ec8e0a23fb8204feeb, https://github.com/Backblaze/B2_Command_Line_Tool, https://github.com/pypa/advisory-database/tree/main/vulns/b2/PYSEC-2022-32.yaml