Timing attack in SASL token signature verification in Apache Pulsar

1) Observable discrepancy

EUVDB-ID: #VU86330

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 - Observable discrepancy

Exploit availability: No

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 - 3.1.0

CPE2.3

• cpe:2.3:a:apache_foundation:pulsar:2.0.0:*:*:*:*:*:*:*
• cpe:2.3:a:apache_foundation:pulsar:2.0.1:*:*:*:*:*:*:*
• cpe:2.3:a:apache_foundation:pulsar:2.1.0:*:*:*:*:*:*:*
• cpe:2.3:a:apache_foundation:pulsar:2.1.1:*:*:*:*:*:*:*
• cpe:2.3:a:apache_foundation:pulsar:2.2.0:*:*:*:*:*:*:*
• cpe:2.3:a:apache_foundation:pulsar:2.2.1:*:*:*:*:*:*:*
• cpe:2.3:a:apache_foundation:pulsar:2.3.0:*:*:*:*:*:*:*
• cpe:2.3:a:apache_foundation:pulsar:2.3.1:*:*:*:*:*:*:*
• cpe:2.3:a:apache_foundation:pulsar:2.3.2:*:*:*:*:*:*:*
• cpe:2.3:a:apache_foundation:pulsar:2.4.0:*:*:*:*:*:*:*

External links

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

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.