Authentication bypass in Synapse

1) Improper Authentication

EUVDB-ID: #VU23098

Risk: Medium

CVSSv3.1: 4.2 [CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: N/A

CWE-ID: CWE-287 - Improper Authentication

Exploit availability: No

Description

The vulnerability allows a remote attacker to bypass authentication process.

The vulnerability exists due to the application does not remove local threepids upon user deactivation and allows access for deactivated accounts.The problem resides within the "/synapse/storage/data_stores/main/registration.py" and "/synapse/handlers/deactivate_account.py" scripts.

A remote attacker can bypass authentication and gain unauthorized access to the application.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Synapse: 1.5.0 - 1.6.0

External links

http://github.com/matrix-org/synapse/releases/tag/v1.6.1

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.