#VU86330 Observable discrepancy in Apache Pulsar - CVE-2023-51437

Vulnerability identifier: #VU86330

Vulnerability risk: High

CVSSv4.0: 8 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/U:Amber]

CVE-ID: CVE-2023-51437

CWE-ID: CWE-203

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Apache Pulsar
Server applications / Conferencing, Collaboration and VoIP solutions

Vendor: Apache Foundation

Description

The vulnerability allows a remote attacker to bypass authentication.

The vulnerability exists due to observable timing discrepancy in SASL authentication provider. A remote attacker can forge a SASL Role Token that will pass signature verification and bypass SASL authentication.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Apache Pulsar: 2.0.0 - 2.0.1, 2.1.0 - 2.11.2, 2.2.0 - 2.2.1, 2.3.0 - 2.3.2, 2.4.0 - 2.4.2, 2.5.0 - 2.5.2, 2.6.0 - 2.6.4, 2.7.0 - 2.7.5, 2.8.0 - 2.8.4, 2.9.0 - 2.9.5, 3.0.0 - 3.0.1, 3.1.0

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External links
https://lists.apache.org/thread/5kgmvvolf5tzp5rz9xjwfg2ncwvqqgl5
https://www.openwall.com/lists/oss-security/2024/02/07/1

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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.