Missing Authorization in Zulip Server

1) Missing Authorization

EUVDB-ID: #VU38928

Risk: Medium

CVSSv4.0: 4.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2017-0896

CWE-ID: CWE-862 - Missing Authorization

Exploit availability: No

Description

The vulnerability allows a remote authenticated user to manipulate data.

Zulip Server 1.5.1 and below suffer from an error in the implementation of the invite_by_admins_only setting in the Zulip group chat application server that allowed an authenticated user to invite other users to join a Zulip organization even if the organization was configured to prevent this.

Mitigation

Install update from vendor's website.

Vulnerable software versions

Zulip Server: 1.3.0 - 1.5.1

CPE2.3

• cpe:2.3:a:zulip:zulip_server:1.3.0:*:*:*:*:*:*:*
• cpe:2.3:a:zulip:zulip_server:1.3.1:*:*:*:*:*:*:*
• cpe:2.3:a:zulip:zulip_server:1.3.2:*:*:*:*:*:*:*

External links

https://github.com/zulip/zulip/commit/1f48fa27672170bba3b9a97384905bb04c18761b
https://groups.google.com/forum/#!msg/zulip-announce/sUYeJv-fFmg/2TU2TLmNAwAJ
https://hackerone.com/reports/224210

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.