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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2021.2339 CVE-2021-32066: A StartTLS stripping vulnerability in Net::IMAP 8 July 2021 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: Ruby Publisher: Ruby Operating System: UNIX variants (UNIX, Linux, OSX) Windows Impact/Access: Provide Misleading Information -- Unknown/Unspecified Reduced Security -- Unknown/Unspecified Resolution: Patch/Upgrade CVE Names: CVE-2021-32066 Reference: ESB-2021.2337 Original Bulletin: https://www.ruby-lang.org/en/news/2021/07/07/starttls-stripping-in-net-imap/ - --------------------------BEGIN INCLUDED TEXT-------------------- CVE-2021-32066: A StartTLS stripping vulnerability in Net::IMAP Posted by shugo on 7 Jul 2021 A StartTLS stripping vulnerability was discovered in Net::FTP. This vulnerability has been assigned the CVE identifier CVE-2021-32066 . We strongly recommend upgrading Ruby. net-imap is a default gem in Ruby 3.0.1 but it has a packaging issue, so please upgrade Ruby itself. Details Net::IMAP does not raise an exception when StartTLS fails with an unknown response, which might allow man-in-the-middle attackers to bypass the TLS protections by leveraging a network position between the client and the registry to block the StartTLS command, aka a StartTLS stripping attack. Affected Versions o Ruby 2.6 series: 2.6.7 and earlier o Ruby 2.7 series: 2.7.3 and earlier o Ruby 3.0 series: 3.0.1 and earlier Credits Thanks to Alexandr Savca for reporting the issue. History o Originally published at 2021-07-07 09:00:00 UTC - --------------------------END INCLUDED TEXT-------------------- You have received this e-mail bulletin as a result of your organisation's registration with AusCERT. The mailing list you are subscribed to is maintained within your organisation, so if you do not wish to continue receiving these bulletins you should contact your local IT manager. If you do not know who that is, please send an email to auscert@auscert.org.au and we will forward your request to the appropriate person. NOTE: Third Party Rights This security bulletin is provided as a service to AusCERT's members. As AusCERT did not write the document quoted above, AusCERT has had no control over its content. The decision to follow or act on information or advice contained in this security bulletin is the responsibility of each user or organisation, and should be considered in accordance with your organisation's site policies and procedures. AusCERT takes no responsibility for consequences which may arise from following or acting on information or advice contained in this security bulletin. NOTE: This is only the original release of the security bulletin. It may not be updated when updates to the original are made. If downloading at a later date, it is recommended that the bulletin is retrieved directly from the author's website to ensure that the information is still current. Contact information for the authors of the original document is included in the Security Bulletin above. If you have any questions or need further information, please contact them directly. Previous advisories and external security bulletins can be retrieved from: https://www.auscert.org.au/bulletins/ =========================================================================== Australian Computer Emergency Response Team The University of Queensland Brisbane Qld 4072 Internet Email: auscert@auscert.org.au Facsimile: (07) 3365 7031 Telephone: (07) 3365 4417 (International: +61 7 3365 4417) AusCERT personnel answer during Queensland business hours which are GMT+10:00 (AEST). On call after hours for member emergencies only. =========================================================================== -----BEGIN PGP SIGNATURE----- Comment: http://www.auscert.org.au/render.html?it=1967 iQIVAwUBYOZ6fONLKJtyKPYoAQjAgA/+KoccraMJxKrHtgar76h2L1q/2eM8P7cq o/C68J1/M3yYYzDSuwvyZy0tr5Hc8EshPQFANCl5MRrA2oVWod3/CQfo1twocAvs 91b7Rt6aUVTBmr2fmCXMOmS9N/ukUfwuXsRGoa9GsLXFjCC8+pFz1HDwPZtdVwCv JHuKoFs8Z2zTGz+AdNderO0NbCwEB10r11U8tfZhCEPjp72eSUscoH4Z0ADokTMU XEh+1biedi4OS7pS8ncYxh1lYYMZ2ZcBqN8F5V6vs5wqOPibZ/OF/PmgR5eD2KEs BYchUcyC7ySK3qrSNsA6nyecepyph2cHROnYC4QYQGM4gF7Xgdx/8FzU2jftsLAy WLmB9NgszLtCYoUl25XeS5aDDA4SpNd3fYmqqIYErp6NmjkfYwerDVWcoshY2hts e6udT+0NBDKvdJYXiuC/YHog4peERvJ8lgZW2Re9hUtNUloU+M7IPm3Odl3OQz/N 3Hrpt+wo4XpzKwkXdu2q7z5drQIgCN5aHLgo6CTTXH2btWY4JxTgY8f6q3RPPKOj 083u8cYNKw0/jXAVyKzLmtvBfjQqgbNBFqjCVaMmfjKdg4mUUlVCpTHik6BLtNzQ XtCjuFk+/XrmVOn+41sJ2GCusHSceEbELGNJm3lmKStvuI2wIR+nvwYsQy8+qxo/ Y1ldJOQtuNw= =KG7o -----END PGP SIGNATURE-----