Bug 2255052 - CVE-2023-48795 proftpd: ssh: Prefix truncation attack on Binary Packet Protocol (BPP) [epel-all]
Summary: CVE-2023-48795 proftpd: ssh: Prefix truncation attack on Binary Packet Protoc...
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Fedora EPEL
Classification: Fedora
Component: proftpd
Version: epel8
Hardware: Unspecified
OS: Unspecified
medium
medium
Target Milestone: ---
Assignee: Paul Howarth
QA Contact: Fedora Extras Quality Assurance
URL:
Whiteboard:
Depends On:
Blocks: CVE-2023-48795
TreeView+ depends on / blocked
 
Reported: 2023-12-18 17:37 UTC by Sandipan Roy
Modified: 2023-12-30 00:41 UTC (History)
2 users (show)

Fixed In Version: proftpd-1.3.8b-1.el9
Doc Type: No Doc Update
Doc Text:
Clone Of:
Environment:
Last Closed: 2023-12-30 00:41:30 UTC
Type: ---
Embargoed:


Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Github proftpd proftpd issues 1760 0 None closed mod_sftp is affected by "Terrapin" Prefix Truncation Attacks in SSH Specification (CVE-2023-48795) 2023-12-27 10:09:40 UTC

Description Sandipan Roy 2023-12-18 17:37:21 UTC
More information about this security flaw is available in the following bug:

http://bugzilla.redhat.com/show_bug.cgi?id=2254210

Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

Comment 1 Sandipan Roy 2023-12-18 17:37:24 UTC
Use the following template to for the 'fedpkg update' request to submit an
update for this issue as it contains the top-level parent bug(s) as well as
this tracking bug.  This will ensure that all associated bugs get updated
when new packages are pushed to stable.

=====

# bugfix, security, enhancement, newpackage (required)
type=security

# low, medium, high, urgent (required)
severity=medium

# testing, stable
request=testing

# Bug numbers: 1234,9876
bugs=2254210,2255052

# Description of your update
notes=Security fix for [PUT CVEs HERE]

# Enable request automation based on the stable/unstable karma thresholds
autokarma=True
stable_karma=3
unstable_karma=-3

# Automatically close bugs when this marked as stable
close_bugs=True

# Suggest that users restart after update
suggest_reboot=False

======

Additionally, you may opt to use the bodhi web interface to submit updates:

https://bodhi.fedoraproject.org/updates/new

Comment 2 Fedora Update System 2023-12-21 18:38:01 UTC
FEDORA-EPEL-2023-b698d8c031 has been submitted as an update to Fedora EPEL 9. https://bodhi.fedoraproject.org/updates/FEDORA-EPEL-2023-b698d8c031

Comment 3 Fedora Update System 2023-12-22 03:03:38 UTC
FEDORA-EPEL-2023-b698d8c031 has been pushed to the Fedora EPEL 9 testing repository.

You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-EPEL-2023-b698d8c031

See also https://fedoraproject.org/wiki/QA:Updates_Testing for more information on how to test updates.

Comment 4 Paul Howarth 2023-12-27 10:09:41 UTC
Note regarding EPEL-8 (proftpd 1.3.6e) and EPEL-7 (proftpd 1.3.5e):

The attack described in this CVE involves interfering with the SSH extension negotiation protocol to downgrade security features, which can be done unnoticed when the ciphers in use are either chacha20-poly1305 or one of the Encrypt-Then-MAC (ETM) ciphers.

In proftpd, SSH extension negotiation support was added in version 1.3.7, ETM cipher support was added in version 1.3.8 and chacha20-poly1305 will be available in the upcoming 1.3.9 release.
Hence, there is no exposure to this vulnerability in EPEL-8 and EPEL-7 due to the lack of support for anything that could actually be downgraded. It can also be argued that the protocol security level in the EPEL-8 and EPEL-7 builds of proftpd is equivalent to those that would be available in a more modern build with this vulnerability present, but that's a reflection of the age of the platform.

The other thing it's important to note is that the affected module in proftpd (mod_sftp) is not enabled by default in any Fedora or EPEL release, and must be explicitly configured in order to be used.

In view of all of this, I do not plan to issue updates for EPEL-8 and EPEL-7 for this issue.

Comment 5 Fedora Update System 2023-12-30 00:41:30 UTC
FEDORA-EPEL-2023-b698d8c031 has been pushed to the Fedora EPEL 9 stable repository.
If problem still persists, please make note of it in this bug report.


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