Improper authorization in Zulip Server

1) Improper Authorization

EUVDB-ID: #VU80017

Risk: Medium

CVSSv4.0: 1.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2023-32678

CWE-ID: CWE-285 - Improper Authorization

Exploit availability: No

Description

The vulnerability allows a remote user to gain access to restricted functionality.

The vulnerability exists due to improper authorization. Authenticated users who used to be subscribed to a private stream, and have since been removed from it, retained the ability to edit messages/topics and delete messages that they used to have access to, if other relevant organization permissions allowed these actions. For example, a user may have still been able to edit or delete their old messages they had posted in such a private stream.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Zulip Server: 1.1.5 - 7.2

CPE2.3

• cpe:2.3:a:zulip:zulip_server:1.1.5:*:*:*:*:*:*:*
• cpe:2.3:a:zulip:zulip_server:1.2.0:*:*:*:*:*:*:*
• cpe:2.3:a:zulip:zulip_server:1.2.0 p1:*:*:*:*:*:*:*

External links

https://github.com/zulip/zulip/security/advisories/GHSA-q3wg-jm9p-35fj

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.

Is there known malware, which exploits this vulnerability?

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