#VU83977 Insufficient entropy in jose4j - CVE-2023-31582

Vulnerability identifier: #VU83977

Vulnerability risk: Medium

CVSSv4.0: 2.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2023-31582

CWE-ID: CWE-331

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
jose4j
Universal components / Libraries / Libraries used by multiple products

Vendor: jose4j

Description

The vulnerability allows a remote attacker to brute-force JWT token.

The vulnerability exists due to usage of insufficient entropy when generating JWT token. A remote attacker can brute-force the JWT token and gain unauthorized access to the application.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

jose4j: 0.1.0 - 0.9.2

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External links
https://bitbucket.org/b_c/jose4j/issues/203/insecure-support-of-setting-pbe-less-then
https://github.com/KANIXB/JWTIssues/blob/main/jose4j%20issue.md

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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.