#VU64805 Input validation error in crypto - CVE-2021-43565

Vulnerability identifier: #VU64805

Vulnerability risk: Medium

CVSSv4.0: 6.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2021-43565

CWE-ID: CWE-20

Exploitation vector: Network

Exploit availability: No

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

Vendor: Go

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to insufficient validation of user-supplied input when parsing a Signer to ServerConfig.AddHostKey in cases where the Signer passed to AddHostKey does not implement AlgorithmSigner or the Signer passed to AddHostKey returns a key of type “ssh-rsa” from its PublicKey method. A remote attacker can pass specially crafted input to the application and perform a denial of service (DoS) attack.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

crypto: 0.0.0-20220314234659-1baeb1ce4c0b

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External links
https://pkg.go.dev/vuln/GO-2021-0356

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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.