#VU66482 Use of a broken or risky cryptographic algorithm in Botan - CVE-2021-40529

Vulnerability identifier: #VU66482

Vulnerability risk: Low

CVSSv4.0: 1.7 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2021-40529

CWE-ID: CWE-327

Exploitation vector: Network

Exploit availability: No

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

Vendor: Randombit

Description

The vulnerability allows a remote attacker to gain access to sensitive information.

The vulnerability exists due to incorrect ElGamal implementation in Botan, which allows plaintext recovery. A remote attacker can perform a cross-configuration attack against OpenPGP and recover encrypted data.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Botan: 2.0.0 - 2.0.1, 2.1.0 - 2.18.1, 2.2.0, 2.3.0, 2.4.0, 2.5.0, 2.6.0, 2.7.0, 2.8.0, 2.9.0

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External links
https://ibm.github.io/system-security-research-updates/2021/07/20/insecurity-elgamal-pt1
https://ibm.github.io/system-security-research-updates/2021/09/06/insecurity-elgamal-pt2
https://github.com/randombit/botan/pull/2790
https://eprint.iacr.org/2021/923
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/UPHGYWNJQKWLTUWBNSFB4F66MQDIL3IB/
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/72NB4OLD3VHJC3YF3PEP2HKF6BYURPAO/
https://security.gentoo.org/glsa/202208-14

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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.