#VU83312 Authorization bypass through user-controlled key in ZooKeeper - CVE-2023-44981

Vulnerability identifier: #VU83312

Vulnerability risk: Medium

CVSSv4.0: 6.9 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2023-44981

CWE-ID: CWE-639

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
ZooKeeper
Server applications / Database software

Vendor: Apache Foundation

Description

The vulnerability allows a remote attacker to bypass authorization process.

The vulnerability exists due to improper implementation of SASL Quorum Peer authentication. The instance part in SASL authentication ID, which is listed in zoo.cfg server list, is optional and if it's missing, the authorization check will be skipped. As a result an arbitrary endpoint could join the cluster and begin propagating counterfeit changes to the leader, essentially giving it complete read-write access to the data tree.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

ZooKeeper: 3.0.0 - 3.9.0

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External links
https://lists.apache.org/thread/wf0yrk84dg1942z1o74kd8nycg6pgm5b
https://www.openwall.com/lists/oss-security/2023/10/11/4
https://lists.debian.org/debian-lts-announce/2023/10/msg00029.html
https://www.debian.org/security/2023/dsa-5544

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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.