CVE-2021-21274
"Synapse Federation Denial of Service"
Description
Synapse is a Matrix reference homeserver written in python (pypi package matrix-synapse). Matrix is an ecosystem for open federated Instant Messaging and VoIP. In Synapse before version 1.25.0, a malicious homeserver could redirect requests to their .well-known file to a large file. This can lead to a denial of service attack where homeservers will consume significantly more resources when requesting the .well-known file of a malicious homeserver. This affects any server which accepts federation requests from untrusted servers. Issue is resolved in version 1.25.0. As a workaround the `federation_domain_whitelist` setting can be used to restrict the homeservers communicated with over federation.
INFO
Published Date :
Feb. 26, 2021, 6:15 p.m.
Last Modified :
Nov. 7, 2023, 3:29 a.m.
Source :
[email protected]
Remotely Exploitable :
Yes !
Impact Score :
3.6
Exploitability Score :
2.8
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2021-21274.
| URL | Resource |
|---|---|
| https://github.com/matrix-org/synapse/commit/ff5c4da1289cb5e097902b3e55b771be342c29d6 | Patch Third Party Advisory |
| https://github.com/matrix-org/synapse/pull/8950 | Patch Third Party Advisory |
| https://github.com/matrix-org/synapse/releases/tag/v1.25.0 | Third Party Advisory |
| https://github.com/matrix-org/synapse/security/advisories/GHSA-2hwx-mjrm-v3g8 | Patch Third Party Advisory |
| https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TNNAJOZNMVMXM6AS7RFFKB4QLUJ4IFEY/ |
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2021-21274 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2021-21274 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Modified by [email protected]
May. 14, 2024
Action Type Old Value New Value -
CVE Modified by [email protected]
Nov. 07, 2023
Action Type Old Value New Value Added Reference GitHub, Inc. https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TNNAJOZNMVMXM6AS7RFFKB4QLUJ4IFEY/ [No types assigned] Removed Reference GitHub, Inc. https://lists.fedoraproject.org/archives/list/[email protected]/message/TNNAJOZNMVMXM6AS7RFFKB4QLUJ4IFEY/ -
Reanalysis by [email protected]
Oct. 24, 2022
Action Type Old Value New Value Removed CWE NIST CWE-400 Added CWE NIST CWE-770 -
Modified Analysis by [email protected]
Nov. 23, 2021
Action Type Old Value New Value Changed Reference Type https://lists.fedoraproject.org/archives/list/[email protected]/message/TNNAJOZNMVMXM6AS7RFFKB4QLUJ4IFEY/ No Types Assigned https://lists.fedoraproject.org/archives/list/[email protected]/message/TNNAJOZNMVMXM6AS7RFFKB4QLUJ4IFEY/ Mailing List, Third Party Advisory Added CWE NIST CWE-400 Added CPE Configuration OR *cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:* -
CVE Modified by [email protected]
Aug. 02, 2021
Action Type Old Value New Value Added Reference https://lists.fedoraproject.org/archives/list/[email protected]/message/TNNAJOZNMVMXM6AS7RFFKB4QLUJ4IFEY/ [No Types Assigned] -
Initial Analysis by [email protected]
Mar. 05, 2021
Action Type Old Value New Value Added CVSS V2 Metadata Victim must voluntarily interact with attack mechanism Added CVSS V2 NIST (AV:N/AC:M/Au:N/C:N/I:N/A:P) Added CVSS V3.1 NIST AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H Changed Reference Type https://github.com/matrix-org/synapse/commit/ff5c4da1289cb5e097902b3e55b771be342c29d6 No Types Assigned https://github.com/matrix-org/synapse/commit/ff5c4da1289cb5e097902b3e55b771be342c29d6 Patch, Third Party Advisory Changed Reference Type https://github.com/matrix-org/synapse/pull/8950 No Types Assigned https://github.com/matrix-org/synapse/pull/8950 Patch, Third Party Advisory Changed Reference Type https://github.com/matrix-org/synapse/releases/tag/v1.25.0 No Types Assigned https://github.com/matrix-org/synapse/releases/tag/v1.25.0 Third Party Advisory Changed Reference Type https://github.com/matrix-org/synapse/security/advisories/GHSA-2hwx-mjrm-v3g8 No Types Assigned https://github.com/matrix-org/synapse/security/advisories/GHSA-2hwx-mjrm-v3g8 Patch, Third Party Advisory Added CPE Configuration OR *cpe:2.3:a:matrix:synapse:*:*:*:*:*:*:*:* versions from (including) 0.99.0 up to (excluding) 1.25.0
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2021-21274 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2021-21274
weaknesses.
Exploit Prediction
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days.
0.17 }} 0.01%
score
0.54430
percentile