Updated advisory posts against rubysec/ruby-advisory-db@5e77a68

Author: jasnow

advisories/_posts/2024-09-17-CVE-2024-8796.md

@@ -0,0 +1,70 @@
+---
+layout: advisory
+title: 'CVE-2024-8796 (devise-two-factor): Devise-Two-Factor Authentication Uses Insufficient
+  Default OTP Shared Secret Length'
+comments: false
+categories:
+- devise-two-factor
+advisory:
+  gem: devise-two-factor
+  cve: 2024-8796
+  ghsa: qjxf-mc72-wjr2
+  url: https://github.com/devise-two-factor/devise-two-factor/security/advisories/GHSA-qjxf-mc72-wjr2
+  title: Devise-Two-Factor Authentication Uses Insufficient Default OTP Shared Secret
+    Length
+  date: 2024-09-17
+  description: |
+    ### Summary
+    Under the default configuration, Devise-Two-Factor version
+    >= 2.2.0 & < 6.0.0 generate TOTP shared secrets that are 120 bits
+    instead of the 128-bit minimum defined by
+    [RFC 4226](https://datatracker.ietf.org/doc/html/rfc4226).
+    Using a shared secret shorter than the minimum to generate a
+    multi-factor authentication code could make it easier for an
+    attacker to guess the shared secret and generate valid TOTP codes.
+
+    ### Remediation
+    Devise-Two-Factor should be upgraded to version v6.0.0 as soon
+    as possible. After upgrading, the length of shared secrets and
+    TOTP URLs generated by the library will increase since the new
+    shared secrets will be longer.
+
+    If upgrading is not possible, you can override the default
+    `otp_secret_length` attribute in the model when configuring
+    `two_factor_authenticable` and set it to a value of at least
+    26 to ensure newly generated shared secrets are at least
+    128-bits long.
+
+    After upgrading or implementing the workaround, applications
+    using Devise-Two-Factor may wish to migrate users to the new
+    OTP length to provide increased protection for those accounts.
+    Turning off OTP for users by setting `otp_required_for_login`
+    to false is not recommended since it would leave accounts
+    unprotected. However, you may wish to implement application
+    logic that checks the length of a user's shared secret and
+    prompts users to re-enroll in OTP.
+
+    ### Background
+    Devise-Two-Factor uses [ROTP](https://github.com/mdp/rotp) to
+    generate shared secrets for TOTP. In ROTP < 5.0.0, the first
+    argument to the "ROTP::Base32#random_base32" function represented
+    the number of bytes to read from SecureRandom which were then
+    returned as a base32-encoded string. In ROTP 5.1.0, this function
+    was changed so that the first argument now represents the length
+    of the base32-encoded string returned by the function instead
+    of the number of bytes to read from SecureRandom resulting in
+    a shorter key being generated for the same input value.
+    (https://github.com/mdp/rotp/commit/c6c24ab894e7c2b1579d45ac82c41454d1e98227).
+  cvss_v3: 5.3
+  cvss_v4: 6.0
+  unaffected_versions:
+  - "< 2.2.0"
+  patched_versions:
+  - ">= 6.0.0"
+  related:
+    url:
+    - https://nvd.nist.gov/vuln/detail/CVE-2024-8796
+    - https://github.com/devise-two-factor/devise-two-factor/security/advisories/GHSA-qjxf-mc72-wjr2
+    - https://github.com/devise-two-factor/devise-two-factor/commit/cc6f34423d9c6af9f3e02be478c3c40dc7462e19
+    - https://github.com/advisories/GHSA-qjxf-mc72-wjr2
+---