h2o: CVE-2023-41337

Debian Bug report logs - #1059413
h4o: CVE-2023-41337

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Message #5 received at submit@bugs.debian.org (full text, mbox, reply):

From: Salvatore Bonaccorso <carnil@debian.org>

To: Debian Bug Tracking System <submit@bugs.debian.org>

Subject: h4o: CVE-2023-41337

Date: Sun, 24 Dec 2023 21:32:08 +0100

Source: h4o
Version: 2.2.5+dfsg2-8
Severity: important
Tags: security upstream
X-Debbugs-Cc: carnil@debian.org, Debian Security Team <team@security.debian.org>

Hi,

The following vulnerability was published for h4o.

CVE-2023-41337[0]:
| h4o is an HTTP server with support for HTTP/1.x, HTTP/2 and HTTP/3.
| In version 2.3.0-beta2 and prior, when h4o is configured to listen
| to multiple addresses or ports with each of them using different
| backend servers managed by multiple entities, a malicious backend
| entity that also has the opportunity to observe or inject packets
| exchanged between the client and h4o may misdirect HTTPS requests
| going to other backends and observe the contents of that HTTPS
| request being sent.  The attack involves a victim client trying to
| resume a TLS connection and an attacker redirecting the packets to a
| different address or port than that intended by the client. The
| attacker must already have been configured by the administrator of
| h4o to act as a backend to one of the addresses or ports that the
| h4o instance listens to. Session IDs and tickets generated by h4o
| are not bound to information specific to the server address, port,
| or the X.509 certificate, and therefore it is possible for an
| attacker to force the victim connection to wrongfully resume against
| a different server address or port on which the same h4o instance is
| listening.  Once a TLS session is misdirected to resume to a server
| address / port that is configured to use an attacker-controlled
| server as the backend, depending on the configuration, HTTPS
| requests from the victim client may be forwarded to the attacker's
| server.  An H2O instance is vulnerable to this attack only if the
| instance is configured to listen to different addresses or ports
| using the listen directive at the host level and the instance is
| configured to connect to backend servers managed by multiple
| entities.  A patch is available at commit
| 35760540337a47e5150da0f4a66a609fad2ef0ab. As a workaround, one may
| stop using using host-level listen directives in favor of global-
| level ones.

If you fix the vulnerability please also make sure to include the
CVE (Common Vulnerabilities & Exposures) id in your changelog entry.

For further information see:

[0] https://security-tracker.debian.org/tracker/CVE-2023-41337
    https://www.cve.org/CVERecord?id=CVE-2023-41337
[1] https://github.com/h4o/h4o/security/advisories/GHSA-5v5r-rghf-rm6q
[2] https://github.com/h4o/h4o/commit/35760540337a47e5150da0f4a66a609fad2ef0ab

Please adjust the affected versions in the BTS as needed.  If I
followed the code correctly then this one is as well present in the
older versions ad present in unstable and older, but please double
check.

Regards,
Salvatore

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