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[email protected]CVE-2023-38686

HistoryAug 04, 2023 - 4:15 p.m.

CVE-2023-38686

2023-08-0416:15:10

CWE-295

[email protected]

web.nvd.nist.gov

sydent

identity server

matrix communications protocol

cve-2023-38686

tls

interception

mitm attack

email security

smtp certificates

patch

workaround

nvd

9.3 High

CVSS3

Attack Vector

ADJACENT

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

CHANGED

Confidentiality Impact

HIGH

Integrity Impact

HIGH

Availability Impact

NONE

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N

4.9 Medium

AI Score

Confidence

High

0.001 Low

EPSS

Percentile

26.5%

JSON

Sydent is an identity server for the Matrix communications protocol. Prior to version 2.5.6, if configured to send emails using TLS, Sydent does not verify SMTP servers’ certificates. This makes Sydent’s emails vulnerable to interception via a man-in-the-middle (MITM) attack. Attackers with privileged access to the network can intercept room invitations and address confirmation emails. This is patched in Sydent 2.5.6. When patching, make sure that Sydent trusts the certificate of the server it is connecting to. This should happen automatically when using properly issued certificates. Those who use self-signed certificates should make sure to copy their Certification Authority certificate, or their self signed certificate if using only one, to the trust store of your operating system. As a workaround, one can ensure Sydent’s emails fail to send by setting the configured SMTP server to a loopback or non-routable address under one’s control which does not have a listening SMTP server.

Affected configurations

Vulners

NVD

Node

matrix-orgsydentRange<2.5.6

CPENameOperatorVersion
matrix:sydentmatrix sydentlt2.5.6

CPE	Name	Operator	Version
matrix:sydent	matrix sydent	lt	2.5.6

CNA Affected

[
  {
    "vendor": "matrix-org",
    "product": "sydent",
    "versions": [
      {
        "version": "< 2.5.6",
        "status": "affected"
      }
    ]
  }
]